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Space rocket launch using vertical rocket sled

Rocket sled is proposed to be used launching space rockets. They are in some degree positioned upwards, or horisontal (Hotol). Why not uising rocked sled positioned straight upwards? Now are many private space firms that are developing lightweight space rockets as cheap as possible. Rocket must be as light and efficient as possible. Rockets are launched upwards. Lightweight space rocket can use 100 - 200 m vertical rocket sled, which is in fact lengthened launch tower. Lightest space rocket is “Blue Whale”, 1,7 tons, and many lightweight rockets, including one stage to space (Haas rocket etc.) are being made. Light rocket can be “shoot” upwards using solid rocket booster that is attached to launch tower with sled system, space rocket and booster does not need any explosive bolts etc. connection, the space rocket simply rests against booster and booster pushes it upwards. Near top of launch tower booster has used all fuel and braking mechanism slows down empty booster casing, space rocket continues to upwards. Now rocket has gained speed and acceleration when it leaves launch tower / vertical rocked sled, only then rocket starts its own engines. Very heavy rockets accelerate slowly, Saturn 5 and SpaceX BFR. Even super heavy rocket like BFR can have large solid booster that pushes BFR to fast acceleration until launch tower ends. BFR has then high acceleration speed when it leaves launch tower, and it starts its own engines only then. When empty booster case reaches launch tower top it is braked to zero speed and it drops back to launch pad, braking slows down it before it drops at launch pad, and solid booster is ready to be reloaded and used again.
One booster can be used to boost launch speed of several type of rockets, all rockets that use that launch pad. Simplest solution is system where normal launch tower is used, its not lengthened, booster is just added below rocket and sled / braking system in launch tower. Minimal amount of modifications is needed in launch site. Light rockets can use long 100 - 200 m long launch tower that is used as rocket sled and launch tower.
Light rockets also can use cheap boosters, like JATO / RATO (rocket assisted takeoff) “bottles”. Aircraft do not use them as often as 1960s, but some (Hercules) do, and JATO is used now to launch some unmanned aerial vehicles. Commercial JATO rockets that has about 15 second burning time can be used. They can even be recovered after use if small parachute is if included in them, and reused, if it is cheaper that way. JATO rockets can be “first stage” of some light space rocket, only when they are burned rocket s own main engine start. Rocket with JATO is launched straight upwards, not in some angle like airplane with JATO.
Other cheap solid boosters can be used with new commercial light space rockets. India used SLV, ASLV rockets and then used them as boosters in PSLV rockets, 9 and 12 tons weight. They should be reasonably cheap, so can be used to boost performance of modern light commercial rocket. The “New space” movement has many new private rocket firms that need as cheap space rocket tech as possible.
Whole rocket could be “outsourced” to some cheap country that has rocket manufacturing, only design office is in USA or europe. So in India, China, Pakistan etc. can have “OEM space rocket factory” that makes space rockets according to orders from europe or USA, and only money and is needed if someone wants to make space rocket. Even design of rocket can be outsourced, so someone orders space rocket, gives specs to manufacturer, and manufacturer designs and makes space rocket according those specs, in India, China or Pakistan.
According to some information SpaceX Falcon 9 rocket reused version really costs only about 40% of its selling price. SpaceX has stated that if maximum turnaround time (about 10 days) between launches is used reused Falcon 9 has 5-6 million dollar cost to SpaceX, but selling price must be higher because of design costs, profit etc. Space shuttle never reached “break even” point when it could have been commercial success, 56 flights per shuttle was proposed in each year, and it would have become cheap “aerospaceplane”. But president Reagan signed law 1984 that ended shuttle monopoly in space launches, and made shuttle commercial failure then.
In order to make space rocket as cheap possible, as many as possible launches are needed. It is possible that rocket manufacturer itself invest profit from rocket launches to increase launch schedule. Rocket manufacturer itself can finance cheap scientific satellites or other satellites and launch them, when maximum turnaround time is reached and price of rocket is at its cheapest, rocket manufacturer does not need itself to finance rockets anymore because price is now so low that commercial customers can order cheap rockets as fast as manufacturer can launch them.
Cheap standard series produced scientific satellites, that are offered to universities etc. can be used to gain as many as possible rocket launches. Astronomical satellites etc. Falcon 9 can have 5 m mirror astronomical satellites series produced, 10 - 100 unit series production. BFR can have monolithic 8,4 m beryllium mirror space telescopes, infrared, visible optical, near ultraviolet (LUVOIR) launched to Lagrange point or near earth orbit. Serial production cuts down costs, both telescope and rocket. From Hubble, Herschel and Webb telescopes, their sensors can be used, not just in one space telescope but in many dozen. Smaller space telescopes with 30 - 50 cm mirror can be manufactured and launched cheaply, those smaller astronomical telescopes can be marketed and sold to private persons, they are manufactured in series production of hundreds of units, and are cheap enough that they can be bought just like normal astronomical telescopes of 30 - 50 cm size are sold on earth. So amateur astronomers can buy space telescope of 30 - 50 cm size and are not restricted to use same size telescopes on the ground of earth. Other scientific standardised satellites can be sold and launched to space, some part of their cost is “sponsor paid” by rocket manufacturer that tries to make launch costs as small as possible launching rockets as fast as possible. When this point is reached and price of rocket is at its cheapest rocket manufacturer does not need to “sponsor” launched satellites no more.
Fast aircraft like Mig 31 and F15 are used to launch anti satellite weapons. For some reason commercial satellite launches using same principle is not used. Fast air launch in high altitude would make really economical rocket launch. Mig 31, Mig 41, F15 , F22, Eurofighter Typhoon etc. can be used. Not just solid rockets but liquid rockets, hydrogen / LOX can be used. When those aircraft launch space rockets they seem to be normal fighter versions, but special launcher version can be made, simple modifications, all equipment that is not needed is needed, radar etc, and aircraft is lightened like those fighters that are used to world speed and height records. Fuel can restricted to minimal amount that is just enough to rise to altitude and then plane glides back to earth and just before landing starts its engines again, and with minimal safety reserves. Saved weight of fuel etc. is used to make external load heavier, and one or several underfuselage hardpoints are used to transport one heavy space rocket. Underfuselage hardpoint(s) are hardened to maximum load, structural strengthening of airframe is perhaps needed. Aircrafts modified that way can carry space rockets that can offer really cheap space launch, with reasonable payload. For some reason this has not been made, only military weapons are launched to space using this fast fighter aircraft to altitude launch principle. Heavier aircraft can be used, british (Bristol) “Space cab” launcher concept has specs that are close to Tupolev Tu 160 aircraft. Space cab has additional rocket motor that increases speed from mach 2 to mach 4. Perhaps Tu 160 can be modified for additional rocket use, and air intakes of engines closed when over mach 2 speed is reached, front fuselage modified to mach 4 speed etc.
Space tourism uses in some plans airplanes / rockets that rise to upper atmosphere 60 - 100 km high. Mig 31 or F15 fighter can be modified to “tourist plane”, one pilot in plane nose and then seats for 4 - 6 passangers. Most of jet fuel weight and external weight that normally is in hardpoints is used to rocket fuel, and plane has additional rocket motor (and normal jet engines). When jet engine max altitude is reached rocket motor starts and launches plane to parabolic flight path. If plane reaches very high altitude perhaps some sort of heat protection is needed when plane glides down to atmosphere, or such gliding path is used that it generates less heat. Air intakes are closed when speed is near mach 3 or over. Air intakes can have doors that expand air intake area in high altitude 2-3 times larger than near ground, so jet engines get more thin air, and when rocket engine starts air intakes are closed.
Balloon launch of rockets can lift light rockets economically. If balloon uses hydrogen, when balloon is its maximum altitude and ready to explode because of gas pressure, hydrogen can be transferred using flexible tube to rocket engine that balloon is carrying, during few seconds when rocket starts it uses gaseous hydrogen as propellant (otherwise it uses liquid hydrogen), in rocket chamber and in rocket nozzle also where gaseous hydrogen is used as sort of “afterburner”. After few seconds tube separates from rocket and and rocket goes with its own power to space, but in few seconds large amount of gaseous hydrogen from lifting balloon is used as rocket propellant, both in rocket chamber and rocket nozzle.
There are other topics in Robin Hood Coop forums that are near this subject, “High explosives as rocket propulsion”, “Useful way to use hydrogen in space station”, “Cheap astronomical telescopes”.
The additional solid booster that is used as vertical rocket sled in previous post, it does not need brakes in top of launch tower because hot gases from exhaust nozzles of rocket proper stop sled booster and push it downwards, only near launch pad braking is needed when booster drops back so landing is relatively soft. But this additional sled-booster is not efficient, 50 m/s (5 g) acceleration in 400 m high launch tower with rocked sled booster is just 200 m/s, rocket needs 7000 m/s in low earth orbit and about 1000 m/s more for “delta v” atmospheric drag etc. So only 2,5% addition, so if BFR rocket uses this and has 180 ton payload to low earth orbit it is just 4,5 ton more. If light rocket has 70 m/s (7 g) sled booster and 450 m high tower (launch tower can be like TV mast, slim and high and it has cables anchored to ground that keeps it up), it is still only 250 m/s so only about 1/30th increase of efficiency, so if rocket has 300 kg payload it is only 10 kg more, 310 kg. So less useful method. Electromagnetic catapult can be used with light rockets like used in ships with airplanes. But kilometres long rocket sled or catapult in mountainside is much better idea.
But then another idea: additional liquid, that is not fuel, is pumped to rocket when it rises, it is not pumped to rocket engine, but to nozzle. It is something that does not burn (easily), water?, or boron?, or something. It is only additive to hot exhaust gases, and makes them more faster, more dense etc., something that increases specific impulse (or maybe it has chemical reaction with exhaust gases). So gas flow from exhaust nozzle is combination of rocket engine hot gases and this additional pumped from ground liquid that turns to gas / or reacts with rocket gases and makes some other energetic compound. Most safe is option is just some liquid that increases specific impulse and does not make dangerous (explosive or burning) reaction products with hot rocket nozzle gases. Pumps are in launch tower top, launch tower is 200 m high, and from there it is pumped up to 600 m higher, so combined height is 800 m, only then liquid tubes that are flexible tube material, disconnect. Big rockets accelerate slowly, like Saturn 5, so when rocket reaches 800 m it has received plenty of this specific impulse increasing liquid.
About high speed airplanes: jet fighter airplanes can be modified for satellite rocket carrying duties. They can have strengthtened underbelly hardpoint(s), internal fuel is minimum because plane only needs to flight to altitude and glide back to airfield, only near airfield jet engines are used again. Underwing hardpoints can have additional jet engines that are from surplus old mach 2 military jets, those engines are used in full power only in high altitude, to increase flight ceiling, but those engines takes payload weight from space rocket. In ground jet fighter can use JATO in takeoff, JATO is supported in ground metal stand when connected to plane so no weight to plane, and when JATO is fired it is projected so that it has slightly lift upwards, so it does not bring extra weight to plane but upward lifting force. Also old military surplus naval catapult or electromagnetic catapult can be used in airfield to give plane speed in takeoff. It is possible to have 15 ton (or more) load (space rocket) in fast jet fighter that is stripped off / in minimal jet fuel? Space rocket can be liquid hydrogen / oxygen powered, steaming hydrogen from rocket fuel tank can be directed to jet fighter afterburner and used as “jet fuel”. Engines of plane can be changed to more powerful, for example F 22 that has two F 35 engines, and mach 2 + capacity. Wing area can be increased, wingtips extended, air intakes increased, max load increased etc.
The tourist plane version that is used to lift space tourists to 60 - 80 km height needs rocket engine in plane together with jet engines, if rocket motor uses RP1 and jet engine JP10 same fuel tanks are suitable for both, only liquid oxygen tanks are needed or other oxidizer. Like in space rocket carrying aircraft, all that can be taken off from plane is taken away , radar etc, so pilot sits in radar compartment and behind him is 4-8 passengers, sitting in pairs, where previously was cockpit. Some heat shielding perhaps is also needed, and doors that close air intakes in over mach 3 speeds. But using jet fighter is simpler and faster than make space “tourist plane” from scratch. South Korea is making its Yun Feng ramjet missile to a space rocket version. Such ramjets / scramjets (missiles) can be turned to space rockets for civilian use. Jet fighter can carry ramjet/scramjet rocket, and this is second stage of space launch system (first is jet aircraft), third stage is liquid fuelled (or solid fuelled) rocket that carries the satellite payload. This rocket is connected to ramjet/scramjet vehicle, and this to airplane. Three vehicles of this launch system (jet aircraft, ramjet/scramjet, and rocket) can be used like rocket stages.

Light privately made space rockets need all extra power they can have, so if they have access to russian Syntin fuel they can increase payload, russians used it only in upper stages, but small rockets can use it in all stages. Syntin was expensive for russians, their low kerosene prices, but westeners perhaps have money to buy Syntin. Also tripropellant engine has more specific impulse than bipropellant LOX/RP1. If only small amount of hydrogen is needed to increase specific impulse of LOX/RP1 engine, then LOX/RP1 stage can have tube to upper hydrogen/LOX stage, and through this tube comes hydrogen to tripropellant rocket engine. So second stage has used some of its hydrogen when it separates from first stage, but this is one way to increase specific impulse. “Ecosene” is new rocket fuel made from plastic waste. And “Synthesis of strained high-energy rocket bio-kerosene”. Also cheap additional solid boosters are available (perhaps) for private firms that develop light and cheap space rockets. Those are not so small, indian additional boosters connected to rocket sides are 9 and 12 weighting, from China and other countries perhaps is available cheap and small boosters that can be connected in sides of small 50 - 100 ton rocket.
Big rocket manufacturers can increase their rocket manufacturing if they direct some of their profit from making rockets to sponsoring space satellite programs. Sponsor money does not go to cheaper rocket prices, but for scientific satellite programs, rocket maker can offer cheap series manufactured satellite bus, and for example series manufactured space telescope, with satellite bus and mirror blank, but buyer must arrange mirror polishing and also buyer must have sensors, cameras, electronics etc. for that space telescope. Space telescopes can be different sizes, 12 m fits inside enlarged BFR rocket fairing or 15 m if mirror is sideways and fairing extra wide like some russian rocket fairing that has wide satellite dish inside. Telescope is then short focal length like Herschel space telescope. Large but light single piece (monolithic) mirrors can be made from beryllium etc, although biggest mirror making machinery is 8,4 m nowadays. From 15 m can be go down to small 30 - 50 cm space telescopes that are sold as complete “package” to amateur astronomers and launched like cubesats to space most economical way. When rocket manufacturer offers series manufactured (cheaper than unique designed / manufacured things) standard parts to scientific community, and also sponsors science offering some seed money to those who buy these scientific satellites, rocket manufacturer gets more rocket orders, and in the end rocket mass manufacturing is in its most cheapest. Then when rocket manufacturing has reached its saturated phase and rockets cannot be made any cheaper, rocket manufacturer can keep all profit and not direct part of it to scientific community (seed money, sponsor money), because rockets are now at optimal low price range and their series manufacturing is in full swing. Reused Falcon 9 rocket has minimum turnaround time of 10 days, and several rockets can be used. With 10 rockets rocket can be launched every day. Price is 5-6 million dollar for Falcon 9 plus profit.

In Wikipedia article “Non rocket space launch” in section “Hybrid launch systems” is that if rocket is launched 3000 m high and has 270 m/s additional launch speed it can have as much as 80% more payload. In Quora netpage “Why small rockets typically launch faster”, and physics stackexhange com: “Would it be economical to add counterweight to rocket” is that rockets (non-manrated) accelarate to 10 g and over when their first stage fuel tanks are almost spent, and that rockets (medium and heavy rockets?) spent 40% of their fuel to accelerate to mach1,3 (450 m/s). So it would be much benefit if rocket can accelerate very fast from the beginning. So perhaps vertical rocket sled is then suitable, it is just additional solid booster that push rocket (it is not connected to rocket, it is connected by rails / wheels in launch tower, it just pushes rocket to upwards) until launch tower ends. Launch tower can be 400 - 450 m high and build like TV masts, lightly build with cables that anchors it to ground.
Better would be ALICE rocket fuel booster, that is fueled from ground. If launch tower is 400 m - 450 m high, and top of it is pumps, water can be pumped to top of launch tower, and from there to 750 - 800 m higher, so 1200 - 1250 m is maximum height of ALICE booster. In that height boosters disconnect from rocket, they have parachutes and they land to ground, just before they hit ground they have smal solid brake rockets that make soft landing of empty ALICE booster casings. ALICE has about 300 second specific impulse, less that RP1/LOX but if 50% of fuel is water that is pumped to booster then it is 600 sec impulse. If water is more than 50% then specific impulse is higher than 600s.
Best would be combining three methods together: launching from equator so 460 m/s more speed, and from high altitude, and launching with fast acceleration from beginning. There is Chimborazo mountain in Ecuador, nearest point to space in earth, and near to equator. Light rockets can be launched from top of it. Rocket need no mountaintop to be launched, they can be launched from high plateaus, and use same infrastructure that normal rocket launch uses. That mountain is in plateau 4000 m high, so launching BFR rocket in that ecuadorian plain with ALICE boosters has all three benefits. That would double BFR payload? 5 g acceleration (50 m/s) is 350 m/s in 1200 m high, and 48 m/s is 350 m/s in about 1250 m high, so even BFR rocket, manrated, can be launched with ALICE boosters, with crew. In first 7-7,5 seconds after launch is 4,8 - 5 g acceleration, crew and passengers will tolerate that easily. So manned rockets also can be accelerated to supersonic speed using reusable ALICE boosters. Some light rockets (sounding rockets etc.) have 20 g (200 m/s) acceleration, so at about 1200 m they have 700 m/s speed then. Light rockets do not even need ALICE “fueled in flight” rockets, ordinary expendable solid boosters will do, that are like JATO bottles, burn about 15 seconds and are discarded after then or recovered by parachute. These just make rocket accelerate fast after launch. Best place to launch polar rockets is Pamir plateau, highest plateau of the world, about 6000 m high. So rockets do not need to be in mountaintop to be launched from very high altitude, launching from 4000 m ecuadorian plateau or 6000 m Pamir plateau is like “air launch from ground”. So rockets almost get benefit of air launch but they are launched from ground like all ordinary rockets, they do not need mountains to get to high altitude.
If there would be method of clean nuclear rocket, that does make pollution, that rocket can be launched from ground, not just in space all nuclear rocket designs do. “Clean nuclear thermal rocket”. There is “positron catalyzed fusion drive”, “antimatter catalyzed fission/fusion drive”, “beamed core antimatter drive”, and most promising of all (perhaps): “Clean lithium fission rocket”. If USA would have invested over 40 billion dollars to it, or in other clean super-effective launch system, and not in heavy launch system that has taken over 40 billion dollars and is not even ready yet, perhaps there would be colonies in Mars and Jupiter already now. Even Skylon project that costs 12 billion dollars is less than over 40 billion and Skylon is much more effective than HLS that costs 500 million dollars (or actually much more) in each launch.
In balloon launch of rocket, balloon can be made of hydrogen, when balloon is at maximum altitude at about to explode because of pressure, payload swings to balloon top using special small booster to swing payload there. Payload (rocket) enters balloon top which is hard rigid material, not flexible, and this hard top of balloon is parabolical shape, like big rocket nozzle. Then balloon is exploded using special charge that contains oxidizer if needed. Rocket (balloon payload) rides to space using explosion energy of hydrogen balloon, using balloon hard top as big rocket nozzle. Then rocket s own rocket engine starts and it discards balloon top, and accelerates to space.
For air launch with jet fighter, there is “Aldebaran” project with “MLE trimaran” configuration. It is rocket that uses not only underbelly hardpoints but wing hardpoints also, one rocket with three fuel tanks under fuselage and wings. It disperses the load so underfuselage does not need to carry whole rocket. Rocket sled like in Hotol design can be used in aircraft liftoff, even heavy jumbojet class like An 225 or An 235, when airplanes carry rocket. That rocket sled has wheels so it can be used in every airfield, it replaces plane s own wheels in takeoff and also accelerates airplane together with plane s own engines so that plane can lift heavier loads. An 225 has 250 - 275 ton payload, An 235 more, and modified to rocket sled launch (with wheels) or JATO launch where JATO rockets use metal stand before takeoff so they do not add weight to plane, and when activated JATO rockets prove upward lift that makes negative effect (weight) of JATO rockets to positive (thrust slightly upwards), so no extra weight to plane. Two methods can be combined, firstly rocket sled launches heavy aircraft with its rocket load to air, when plane and rocket sled separate JATO rockets lift plane with its load to higher altitude. With these methods heavy jumbojet class aircrafts can carry even more load that those super heavy aircraft can carry, carrying and launching rockets to space. Also when they launch rocket, they can glide back to airfield, using only minimal amount of fuel, using jet engines only at limited power before landing, saving fuel for payload weight. That MLE project had only 0,7 mach speed in altitude before rocket launch, but those fighter planes are designed to high speed, mach 2 to mach 3 in altitude. So if rocket has high speed, supersonic, in altitude before it is launched that is better.
There is already aircraft designed to launch 250 ton rockets to space, now owned by some investment firm, and light space shuttle (Dream Chaser) is also. So all components of MAKS space shuttle exist. Light fuel tanks were used in space shuttle, and are to be manufactured for HLS. MAKS used tripropellant engine that was version of russian rocket engine that is in production. So at low cost MAKS style space launch system can be made, because all of its components exist already, and need only minimal cost when all those components are brought together (when compared building space launch system, with similar capacity, from scratch). There was also Burlak (Burlak Diana) launched from Tu 160.
There is many new private space rocket firms, and then is United launch Alliance, of big rocket firms. Small rocket firms also need united launch alliance of sorts, some kind of cooperation in rocket launch site use etc., one rocket launch site can be used by all alliance members etc, component manufacturing like payload fairing can be concentrated to one manufacturing facility and all alliance members use it, even although fairings can be different sized etc. For example some rocket can use some other rocket s first stage boosters as two solid boosters in its own rocket s side, if alliance members sell rocket components to each other.
Small space firms are developing aerospike engines. However although USA has been developing aerospike engines from 1960s no it is not used. USA government has much more resources than those small space firms, but space shuttle nor any other rocket uses aerospike, although space shuttle would really needed it. Advanced technology development is then used only in those small space startups. Ducted rocket motor is used in Meteor missile. Making Meteor to satellite launch vehicle is simple, bigger version that can be used in jet fighter to launch satellites to space, with liquid or solid fuel second stage or stages. Ramjet / scramjet designs can also be used, turning missiles to civilian space rockets. They can be even launched from ground without airplane to carry them, with rocket or rocket sled launch. South Korean Yun Feng is example. When that kind of air using satellite launcher drops back to earth, it can glide or use parachute and then recovered by aircraft, or use parachute and brake rockets before it hits ground, or use paraglide, and then reused again. “Slingatron” is another new design.
Using counterweight to accelerate rocket can be perhaps used. It is even patented, “Counterweight based rocket rocket launch platform”. Best is to use big almost vertical mountain sides, that mountain climbers climb when they want extreme difficult mountain climbing experience. Those mountain sides are almost vertical and sometimes also very high. Counterweight can be like big railway car, with wheels. It is filled with sand and rocks and then dropped over cliff, it rolls down the mountainside with wheels , it is connected to cable, cable uses pulley at the edge of the cliff to increase acceleration of rocket that is in mountain valley connected to pulley cable when counterweight comes down, and counterweight is much more heavier than rocket, pulley increases rocket speed, rocket is connected to pulley with cable, pulley with cable to counterweight, rocket rapidly rises from the ground until it reaches cliff where counterweight was dropped, there it starts its rocket engines and goes to space. Counterweight rolls down to mountain valley where rocket previously was.
Big rocket manufacturers pay part of some scientific satellite / space observatory, paying part of its price, expecially situation where satellite project needs seed money to begin, or some satellite has some amount of funding missing to come true. So instead of lowering rocket launch prices, rocket manufacturer can support scientific satellite projects that use this rocket. Rocket launch prices then come down naturally when more and more of those rocket are launched and series production / launching brings economics of scale. Benefit of this is that instead of lowering rocket launch costs that spread benefits between commercial and scientific satellites, this gives 100% of benefit to scientific satellites. And then rocket prices come down anyway when more and more satellites are launched by this rocket. When optimal point is reached (in Falcon 9 that is when 5-6 million dollar cost has SpaceX to manufacture/reuse and launch rocket, but SpaceX also needs profit and to pay design costs) no need to sponsor scientific satellites anymore and increase satellite launches that way because optimal economics of scale is reached in rocket launches.
Of making cheap astronomical space telescopes: these can be like cubesats, manufactured in series production, hundreds, sold to both amateur and professional astronomers, mirror size 30 - 50 cm, they can use inflatable mirrors that fit inside “cubesat” if really low cost is needed, infrared or optical telescopes. Biggest would be 15 m telescope like Herschel space telescope sideways in oversize BFR payload fairing, in unsymmetrical payload fairing. Even 30 m space telescope fits inside BFR if it has foldable mirror like Webb telescope, it can use Webb instruments, it only has bigger mirror and bigger everything, it can use liquid helium in cold mode before its starts use warm mode after helium is depleted. Even 100 m diameter optical telescope that has ring mirror like RATAN 600 radiotelescope can be build in space using big rockets like BFR. That 100 m telescope was proposed in 1990s, and also was proposed HighZ infrared telescope mission to faraway space.
Satellite rockets have 10 - 12 g acceleration when first stage is almost empty, so if 120 m/s acceleration (12 g) is used from launch pad to 1250 m high, 550 m/s is reached. Launch tower can be 450 m high and from there up to 800 m more high, water is pumped to ALICE rocket boosters. 100 m/s acceleration or 10 g is 500 m/s in 1250 m high. 80 m/s or 8 g is 450 m/s in 1250 m high, 60 m/s or 6 g is 380 m/s in 1200 m high. If those calculations are right. Because heavy (and medium) rockets accelerate slowly they would benefit if additional boosters are used in rocket that use fuel (water) that is pumped up from ground, using flexible tubes, and ALICE fuel. Those boosters can be easily reused. Also launch tower can be used as rocket sled, then no exotic fuel like ALICE is needed but ordinary solid propellants, but then launch tower height is the restricting factor. Smallest space rockets like Blue Whale (1790 kg) can easily be launched from mountaintops, those new private space firms are developing lightweight rockets about 50 - 100 ton class that can be transported and launched from mountaintops near equator. Some small space rockets even have their own transporter ejector launcher. In Ecuador plateau or other high place near equator can be launched even biggest of rockets like BFR, to gain additional specific impulse, and polar rockets from Pamir plateu.

Making heavy space rockets to accelerate fast immediately after the launch can bring huge savings, if big rocket uses 40% of its fuel to get 450 m/s speed. Simplest solution would be additional solid or liquid boosters that burn about 15 seconds, and are used together with rocket s own engines. Those boosters are like JATO rockets, and 15 seconds to 450 m/s means 3 g acceleration. If rocket s own engines have 1,4 g acceleration 1,6 g more (16 m/s) is needed in 15 seconds. So rocket like BFR or Blue Origin can accelerate quickly. Those additional solid or liquid boosters can be recovered with parachute, they are 3,4 km high when discarded.
Another way is to use high support structure that extends from launch tower, up to 600 m high. In 600 m high is pumps that pump fuel to additional rocket engines that are at rocket s side. Fuel is on the ground and goes through tubes. Fuel goes through flexible tubes to rocket engines, and also when rocket rises above 600 m pumps keep pumping, and finally at 1200 - 1250 m high tubes disconnect and additional rocket engines are discarded and parachuted back to earth. If acceleration is 50 - 48 m/s (5 g - 4,8 g) 350 m/s speed is available. Even big rockets like BFR can accelerate 4,8 - 5 g.
Fuel is some monopropellant or bipropellant that is relatively safe. Fuel specific impulse is not important, it can be low power rocket propellant, it is pumped from ground during few seconds (7.3 seconds if 48 m/s acceleration is to 1250 m altitude), and also rocket uses its own rocket engines during same time. Hydrogen peroxide (?) or similar, HAN or ADN (?), or similar relatively safe compounds that amateur rocketeers use can be used, liquid fuel. Main point is that either bipropellant or monopropellant is safe fuel, bipropellant perhaps needs two tubes to same rocket engine. How energetic that rocket fuel liquid is, is not so important, it is pumped from ground. Pumps must pump up to 600 - 650 m high and they themselves are at 600 m high, in ground are another pumps that pump upward to 600 m high. But they need to operate only few seconds, about 7 seconds max, until rocket reaches 1250 m. Perhaps fuel pumps themselves can be rocket operated or jet operated, for simplicity. Small rocket or jet engine goes round and round connected to wheel that pumps fuel to tubes.
The structure that holds pumps and tubes at 600 m high is lightweight, like TV mast, with cables that anchor tower to ground.
Another way is vertical rocket sled that extends to 600 - 650 m high. Only rails of rocket sled (which is simply additional stage at the bottom of the rocket, using liquid or solid fuel), extend up to 600 m. Those rails need lightweight support structure only. Now this additional rocket stage stops at 600 m when another stage begins burning its rockets, rocket sled stage and drops back to launch pad. It needs braking system or small braking rockets before it lands in launch pad and is reused. Only 600 - 650 m is then available. This additional stage that burns only few seconds is using its rockets engines at same time when rocket starts in launch pad, and provides additional thrust for fast acceleration. So then those additional rockets need to be at the side of rocket, not in bottom. And instead of of one additional rocket at the bottom of rocket proper now must be at least two rockets in rocket sled, in 9 m diameter distance if BFR rocket is used. Or this additional stage is assembled in bottom of rocket in such way that rocket can use its rocket engines and this additional booster too at same time.
At 600 m high 50 m/s acceleration (5 g) is 250 m/s about. Only 5 seconds of 5 g acceleration is needed, so rocket is manrated. 60 m/s is 270 m/s, 80 m/s is 310 m/s, 100 m/s is 350 m/s and 120 m/s (12 g is often used in satellite launching rockets just before their first stage is empty) is 380 m/s at 600 m high. But better is pumping (safe) fuel to additional rocket engines up to 1200 - 1250 m high, rocket goes then faster.
The problem with ALICE fuel is that its aluminum is unstable and needs additional material (ice) to balance. So some amount of water is needed in rocket stage and not all can be pumped from ground. If all fuel is pumped from ground, rocket needs no additional weight up to 1250 m except those additional engines, and weight of flexible fuel tubes.
When rocket does not need fuel anymore in 1250 m high, only that amount of fuel is in tubes. Then is some kind of moving sealing plug and behind it some liquid (water), or simply air that pushes fuel upwards. So when at 1250 high and rocket fuel tubes are disconnected and go back to earth with rocket engines that use them, tubes have no fuel anymore but air or some other liquid.
Small lightweight rockets can simply use standard commercial JATO / RATO bottles as additional accelerator stage. Even medium rockets can perhaps use them, rounded around rocket hull. Those JATO rockets are used not only in west but in east europe, China, India etc. so cheap JATO bottles can perhaps be bought from there. Or use simple solid rockets that use small parachutes and land back to ground and are reused.
Another way to launch rockets is using high waterfall or dam and water pressure and height distance to launch rocket. Highest waterfalls are at 900 - 700 m high, highest natural dam is almost 600 m high, and highest man made dams about 300 - 250 m high. If vertical tube is carved in rock or build using beton / concrete, and rocket, even biggest like BFR that weights 5000 - 4400 tons, is inside this tube, and tube diameter is larger than rocket bottom, water that drops from high altitude (waterfall, dam) uses hydraulic lift force and hydraulic acceleration force to lift platform inside tube, this platform is big moving plug in tube, platform holds rocket. What is rockets acceleration speed and final speed in tube depends height distance and also water mass and pressure (depth) of river / dam that is higher than rocket in the tube. Even 5000 ton rocket can have acceleration that pushes rocket supersonic speeds or even multi - mach speed inside tube, so some aerodynamic fairing that covers rocket and plug platform is needed, that then looks like gigantic missile warhead inside tube. Air vents are needed in tube sides because plug with rocket when it rises fast up tube pushes air away. When water reaches these vents they are closed. Another way is to make tube sealed and pump air away from it so there is some sort of vacuum. Now rocket rises even faster. When rocket speed is at it highest inside tube aerodynamic fairing that covers fast moving plug (platform and rocket) inside tube is opened and rocked starts its own engines and rises to space. Same construction techniques that are used in water powerplants can be used to building rocket launching hydraulic tube, to control stream from high place to lower place and turning this pressure / height power to fast hydraulic lift. Even heavy 5000 ton rocket can reach over mach 1 speed if rocket stands g forces, before it leaves tube, if 900 m high waterfall is used (river is 900 m higher than ground where rocket is). Some ASAT rockets had 800 m/s acceleration, so nearly 2 mach speed is possible in 900 m distance and 80 g acceleration. 5000 ton rocket when it rises from launch tube has 900 m/s speed and high water pressure makes artificial supersonic geysir that boosts rocket and its launch plug platform even higher altitude. Heavy plug weighting hundredes of tons or 1000 ton uses parachutes and powerful landing rockets to land to ground, or near waterfall / river is artificial lake, tube is slightly pointed towards it so platform plug makes splashdown landing to that lake without any parachutes etc braking system perhaps. From bottom of artificial lake this heavy launching platform plug is salvaged and used again.
Another way that does not need additional rocket engines in land launch is the same liquid pumping from 600 m to 1200 m high but now only some safe liquid (not fuel) is pumped to rocket s own engines. This liquid does not go to rocket chamber, but to nozzle, and this liquid makes rocket exhaust faster, more dense etc. efficiency increasing. So rocket does not need to carry additional fuel to boost speed, but because this liquid is not fuel but safe liquid, additional acceleration perhaps is not much. But this is the safest way. Rocket sled to 600 m high is also safe. What If using rocket sled to 600 m and then pumping this safe liquid that does not go to rocket chamber but rocket nozzles in rocket s own engines to 1200 m height is combined? Perhaps safe method but what acceleration speed is achieved and what liquid (liquids) to use etc.
If rocket uses some bipropellant or monopropellant and fuel tubes from ground and additional engines, the same bipropellant or monopropellant fuel that is used in additional engines that are jettisoned in 1200 - 1250 m high can be pumped to rocket nozzles of rocket proper also. Inside rocket nozzle this additional fuel burns in “afterburner” style and increases acceleration more. But rocket acceleration is restricted to rocket s structural limit, and it can reach those limits using its own engines in normal way and then additional jettisonable thrusters that are discarded in 1200 m high, so “afterburner” is perhaps not needed.
Other concepts: “Rotating pulse detonation engine”, “air turborocket”, “RTR turborocket”. Real advanced concept is clean nuclear rocket that can be used in atmosphere. Clean lithium fission rocket needs only natural uranium that is not so dangerous (natural uranium is in rocks in nature etc.) and only slight amount of tritium is produced that is not so harmful. So rocket has massive specific impulse and is not harmful to enviroment, and can be launched from ground. If over 40 billion dollars that was used to make heavy launch system SLS would have been used to make some of those clean nuclear rockets or SABRE engine etc., that would been much better than conventional rocket that cost 500 million dollar to launch.
Even SABRE engine can be used in otherways ordinary multistage rocket. Rocket engines are most expensive part of rocket so they can be recycled. Ordinary multistage rocket has SABRE engines at its side, every time rocket stage is discarded SABRE engine drops to ground using parachute and is air recovered by airplane or lands to ground using paraglide or ordinary parachute. High altitude stage engines use some sort of wings to glide back to ground. Air intakes are either closed during gliding stage or SABRE with wings has small amount of own fuel in small fuel tank that is used in gliding stage when SABRE engine works in minimal power and then lands to airfield. Because SABRE uses less fuel than ordinary rocket engine rocket can now carry much bigger payload. At launch some ordinary rocket booster can be used until rocket gains speed, and then SABRE engines start.
In “High explosives as rocket propulsion” text in Robin Hood Coop forums is other methods for economical rockets that may work or not. Also “Using water as fuel” text in Robin Hood Coop forums.
Even ordinary jet engines can be used in rocket first stage, jet fighter engines of mach 2,8 - 3,2 capacity. They can be used in light to medium rockets as additional propulsion, they can have own fuel tanks or use some sort of rocket biofuel that replaces RP1 as rocket fuel together with rocket engines. When rocket reaches speeds over mach 2,8 or mach 3,2 engines are discarded and are parachuted to ground, near ground they have small braking rocket charge and small launching legs eject and engine lands. This method can be used to land other rocket engines, ramjets etc.
If ALICE rocket fuel is used in additional rocket engines and water pumped from the ground up to rocket, superheated water 370 C / 700 F can be used, if it increases efficiency.This superheated water can perhaps be used as additional liquid that is pumped to rocket s own rocket nozzles also, if it makes rocket exhaust more efficient. Or use superheated water as component of some safe bipropellant or monopropellant that is pumped from the ground up to rocket etc. There is also different form of water superheating that happens in microwave ovens etc., and does not need overpressure for water remaining in superheated state. One of those superheating forms can be used in superheated water that is pumped to rocket, or both. If microwaves can superheat water, water can be heated in a moment after it comes from pump in 600 m high, so it does not need to be heated on the ground. But water can be used as coolant of rocket nozzles and there it becomes superheated. If rocket uses liquid fuel, some of turbopump power can be used to lift liquid from ground using tubes, but most of pumping power is from 600 m high tower pumps and pumps from the ground. Turbopump style system can be used in pumps in the ground and in 600 m high tower also.

In text “High explosives as rocket propulsion” in Robin Hood Coop forums is that some high explosive, made of long rod, can be used as rocket propellant. This is old space gun principle, but turned upside down, gun does not shoot to space but towards ground. If rocket is 300 m high and explosive rod is 10 m long, it is loaded to “gun barrel” 300 m long and shooted to high velocity. When it enters rocket nozzle it has high speed so when it explodes (burns fast) it at the same time moves so fast that explosion happens inside nozzle. Rocket nozzle is some hard material. Most energetic and energy dense explosive can be used. Although specific impulse of explosives is not as much as hydrogen / oxygen, explosion releases much energy, more than rocket propellant. If explosive rod has 10 000 m/s explosion velocity, and it moves 10 000 m/s when comes to nozzle, it has then 20 000 m/s combined exhaust gas velocity. Also recoil of the “gun” that launches this explosive rod pushes rocket upwards. Liquid or solid gun propellant can be used, or another explosive to propel the rod. Gun barrel must be strong but relatively light material, and rocket nozzle also. Rapid fire system must be used, and payload capsule at top of the rocket has some vibration damping mechanism. 300 m high rocket itself is just magazine of 10 m long explosive rods and gun barrel / rod loading system (or many of them). Explosive rods can also be longer, up to 50 m long perhaps, loaded sideways to “gun barrel”. So this is single stage to orbit, but perhaps OTRAG style staged rocket can be made coupling those gun / rockets together. “Gun rockets” can be made reusable like Falcon 9 or made to spaceplane style system.
If ordinary chemical rocket is used, and first stage uses ALICE fuel, its water tanks can be empty during liftoff, from the ground is pumped water to its rocket engine up to 1250 m high, and also its water tank is filled at the same time, so rocket has at launch empty water tank but it is filled up when rocket reaches 1250 m high. 600 m high tower is used where are additional pumps, and rocket itself can use some of its fuel turbopump power to lift water from the ground. Water can be superheated in rocket nozzle, used as coolant, before it enters rocket engine. Bad thing about this scenario is that if rocket accelerates for example 50 m/s ( 5 g) fast, only 7 - 7,5 seconds is the time tank must be filled, and fuel (water) is needed hundreds of tons and at same time it burns in rocket engine also. Big rocket like BFR needs over 1000 tons of water if it uses ALICE in its first stage. But big rockets accelerate very slowly. So rocket acceleration is not at its most slowest in the launchpad but at 1250 m high when its first stage tank is pumped full.
Also fuel that decomposes to another fuel can be used. If ALICE rocket uses water as fuel, burning rocket fuel that makes water (and oxygen or hydrogen also) can be used as some sort of two chamber rocket engine where ALICE is the second chamber, or aluminum is just pumped to rocket nozzle where it burns with water vapour in afterburner style. Potassium permangate and hydrogen peroxide burn makes water and oxygen, hydrogen peroxide monopropellant burn makes water and oxygen, both can be used with ALICE, and burned HAN rocket fuel makes water and hydrogen, suitable for ALICE too. Hydrogen / oxygen burning makes water, so hydrogen/LOX rocket can use aluminum as “tripropellant” in some second chamber after hydrogen/LOX is burned in first chamber, or aluminum goes straight to rocket nozzle and burns there. Not pure aluminum perhaps, but ALICE slush. This rocket engine has very high specific impulse.
ALICE aluminum can perhaps be processed so that it does not need 50/50 aluminum / ice mixture but for example 70 % aluminum and 30% ice. Another way is that in this additional water that is not with contact with aluminum has additional compound, oxidiser or something, so that ALICE slush does not need to include it, so that makes aluminum more stable. Aluminum can also have some binder / compound like high explosives have that keep them stable, so only aluminum plus binder / compound is needed and water is not included in fuel mix, so only aluminum (plus binder) is in tank and water can be in separate tank or it is brought from outside, for example burning product of another fuel (vapor steam) is used as fuel. Or pumped from ground.
Hydrogen peroxide as rocket concentration is dangerous, but amateur rocketeers use 50/50 hydrogen peroxide / water mix and that is safe, and in vernier rockets before was used low concentration hydrogen peroxide. Even 35/65 mix can be used if it can be pumped from ground safely, water in the mix is fuel too in ALICE rocket.
Any rocket fuel, monopropellant, bipropellant or even tripropellant, whose burning makes water and perhaps oxygen or hydrogen too can be used in “two stage” rocket engine that perhaps has two rocket chambers, second chamber is ALICE and first chamber uses this other rocket fuel, or aluminum / ALICE just goes to rocket nozzle in afterburning style.
Other safe fuels that can be pumped to rocket up to 1250 m high can perhaps be nitrous oxide / amine, and perhaps liguid air (instead of liquid oxygen) can be used although liquid air is not so safe, but safer than oxygen. It is worse oxidiser than oxygen but fuel is pumped from ground to 1250 m high and all is burned when rocket reaches that height so weight of fuel does not matter much. Hydrogen peroxide with DMAZ has been studied. “Energetic ionic liquids” are new class of safe rocket propellants, subclass of “energetic liquids”. Those can be perhaps used as safe fuel to be pumped from ground to rocket. If rocket first stage uses energetic ionic liquids first stage fuel tanks can be empty in launch pad, only when rocket rises to 1250 m high they are pumped to full. But again acceleration time can be such short that only few seconds is available for pumping.
Also air breathing engines like SABRE, air turborocket, RTR turborocket, ramjet or scramjet can be used. Rocket can be ordinary multistage rocket, only engines are air breathing / rocket hybrid engines. Those engines can be parachuted or flown back to earth, fuel tanks not. Those fuel tanks can be manufactured in some cheap country, like India or China. So only reusable engines are attached to those cheap non reusable fuel tanks. SABRE etc. rocket can use vertical launch sled or other method to gain fast speed in the beginning.
“The impossible became possible with new super rocket engine”.
It is possible to use principle of “double burn” rocket fuel, where burning products of one fuel are used as fuel together with another fuel and burned again (water vapor, oxygen, hydrogen) and every stage of three stage rocket can have “double burn” engine, so rocket has then (theoretically) about 50% more efficiency (when first fuel is burned it produces exhaust gases, mixed with 50% fuel 50% exhaust gas in second rocket chamber or straight in rocket nozzle this brings 50% more power?). Although this is highly simplified presentation.
Some moon colonisation studies (lunar org netpage “Liquid metal alloy oxygen rocket”) have rocket propellant with aluminum and some other materials.
High flying jet planes carrying and launching space rockets can use special high altitude high energy jet fuel. Methanol isopropanol nitromethane mix? JP-X as jet fuel? Those planes can have special high altitude flaps.

There are studies of “Electrically powered spacecraft propulsion”. Those propulsion system have so small thrust that they can only be used in space, although “magnetohydrodynamic propulsion” is studied in atmospheric vehicles and spaceplanes. There are plans of “beamed propulsion”, using microwaves or laser to propel spacecraft to space.
But beamed propulsion is not needed, only thing that those “beamed propulsion” rockets and spaceplanes need is long electric wire. So long wire that it reaches space. Those electrically powered spacecrafts drag behind them long electric wire that provides electric propulsion power for them. They don t need microwaves and lasers, but long electric wire. Superconducting electric wire, low temperature superconducting wire, or high temperature superconducting wire. Low temperature superconducting wire only needs to work those few minutes when spacecraft rises to space, then it may stop working. Light isolation materials for isolating pure electric wire can be used, and wire itself can be some light superconducting material.
Wire does not need to have about 200 km or (much) more length that is enough for spacecraft to reach space, only first stage of rocket can be electrically powered, and this first stage reaches only few dozen kilometres off the ground or less, so only few dozen kilometres long electric wire is needed. Next stages are chemical rocket, SABRE, scramjet etc.
There is “Electrodynamic tether” principle, this superconducting wire when rises to space and moves with rocket can be used as electrodynamic tether generator, providing even more electric power to spacecraft.
Wire weight that spacecraft must drag behind itself can be eased, helium or steam balloon can be in 15 km height that is holding this electric cable. In lower altitudes can be other balloons that hold this cable too, in certain intervals so that weight of cable to rising spacecraft is minimal. Those balloons are anchored with anchor cables to ground. Now electric cable has minimal weight to rocket / spacecraft. If spacecraft rises to space with electric power it needs perhaps 200 km or longer cable and this balloons supporting electric cables - method is not so effective.
But those balloons can also be used for holding fuel tubes of chemical rockets when they are fueled when rising to space. So chemical rocket can have empty tanks until it reaches 15 km height, its rocket motors get fuel from ground and those balloons have pumps that pump fuel too. Just before rocket reaches 15 km its fuel tank (or tanks) is / are filled with fuel.
About vertical rocket sled / catapult: Electric motors can be used to lift rocket in 600 m high vertical lift or catapult system. It even can have counterweights like traditional lift. Or lift can be made by electrically powered gearwheel system. Another way is steam catapult but instead it generates gas by some chemical reaction, this gas pushes steam piston of vertical catapult and rocket upwards. Or use some really big boiler to generate steam.
Two 600 m high towers are perhaps needed because of balance if launch system of catapult is not rocket powered (meaning additional rocket stage is just added bottom of the rocket that burns up to 600 m height).
Another way is to use hydraulic lift to lift rocket, hydraulic motors and lift off system that is powered by gas turbines or diesel engines. Gas turbines and diesel engines that drive hydraulic motors can be themselves used with mechanical connection (gearwheels etc.) to liftoff system so hydraulic system is not needed. Big diesel engines used in supertankers have very high torque, bigger than gas turbines.
Electric propulsion that is used in modern aircraft carrier catapults can also be used, but then is needed 600 m high vertical catapult that can lift hundreds of tons or two of 600 m high catapults (or more).
So vertical catapult can use electric motors, or then diesel-electric system, diesel engines with mechanical lift system, diesel-hydraulic system, gas turbine with hydraulic motors, gas turbine electric- or gas turbines with mechanical connection, or gas generator catapult or steam catapult, or electric propulsion system used in modern aircraft carrier catapults. And lastly electric- hydraulic lift system (vertical catapult) can be used. Lift system can use counterweights like elevator, or not.
Balloons that lift either electric wire or fuel tubes to high altitude can be steam balloons in low altitude and helium balloons in high, if that is the best solution. Balloon heights are staged so that they are optimal with rocket / spaceplane speed and acceleration. How many balloons are needed? 10? 20? 30? Or more? And altitudes as high as 20 km or 30 km can be used, so that last balloon is 30 km high and other balloons below it. So rockets / spaceplanes get fuel or electric power propulsion up to 30 km high.

Another way is to use thunderstorm power to gather energy to spacecraft, this electric wire that powers spacecraft is used as thunder conductor at the same time. This is “free energy”. Lightning hits electric wire that is connected to spacecraft and this electric energy propels spacecraft to space. When lightning is not striking electric power comes from the ground. Spacecraft is dragging behind itself one or several electric wires, one of them connected to ground where comes electric power when lightning is not striking. This spacecraft system is in mobile platform so that it can follow thunderstorms everywhere. Launch system uses wheeled transporter ejector launcher when moving along roads, or train or ship when heavy rocket / spaceplane is used. This launch system is assembled from several modules packed in train railway containers before liftoff, or in ship this rocket / spaceplane is in complete form and only needs to be launched when ship enters thunderstorm area. Spacecrafts are designed so that they can survive thunderstorms and fly through them to space.
If gas turbines or diesel engines are used to provide vertical catapult power to lift rockets fast, those gas turbines or diesel engines can be used as electric powerplant when they are not used launching rockets. In cases where gas turbine - electric catapult is used or diesel - electric. But if gas turbines and diesel engines are directly mechanically connected to lift system (gearwheels etc.) they can still have additional electric generators that can be used only when turbines or diesel motors are used as electric powerplant. So rocket launching site can have double use as electric powerplant providing electric power when electric network needs extra electric power in that time when peak power is needed in electric network.
Spacecraft does not carry or “drag” behind electric wire, it is fed from the ground and also balloons have wire feeding mechanism. So spacecraft does not need huge electric wire store, wire is fed to spacecraft by balloons that has special electric motors or pumps that feed wire at high and then is ground wire feeding mechanism. Another way is that wire is hanging loose near ground from balloons and when spacecraft accelerates wire is getting tighter. Those two methods, hanging loose wire from balloons and wire feeding mechanism in balloons and on the ground can be combined. But wire must travel several kilometres per second perhaps, and in low earth orbit 8 km/sec speed is needed, so wire feeding mechanism must be really fast. There is no drag because of wire, spacecraft just receives wire from feeding mechanism as fast as spacecraft travels, but weight of the that wire hanging in the air between nearest balloon and spacecraft must spacecraft carry. Also fuel tube for chemical rockets can use these methods, but again fuel tube feeding mechanism must be fast. If only first stage of rocket uses electric power and only few dozen kilometres range wire is needed, this wire feeding becomes more practical. For chemical rockets only possible solution is first stage only fueled in air.

About launching electrically powered spacecrafts to space: If electric wire is fed to spacecraft and power comes from the ground, that wire is superconductor, and perhaps then liquid helium or liquid hydrogen can be pumped to this electric cable. It keeps wire superconductor and cold. Liquid helium or hydrogen is pumped from the ground to wire and it comes to spacecraft, perhaps boiling, but its is still enough cold for low temperature superconductor. And hydrogen when it enters to spacecraft can be used as propulsion propellant there. Such electric cable that it has just enough length to work as superconductor that is maximum distance from nearest pumping place (balloon or aircraft). When spacecraft reaches required speed and distance and wire is at is maximum length superconductivity ends and cable is disconnected.
Also aircrafts can be used to carry and hold electric cable, perhaps many of them. Before spacecraft is launched electric cable is connected to it and from there it goes to group of aircrafts in nearby airfield. Aircrafts takeoff before spacecraft is launched and lift cable from ground. When spacecraft is launched it moves not only vertically but also horisontally because it is going to orbit. Airplane or several airplanes follow this flightpath flying to specified direction, altitude and speed. If series of airplanes is used each airplane is connected with electric cable to next one, from low altitude plane to higher flying plane. From lowest flying airplane cable goes to ground where electric power is coming. Freight airplanes can carry 120 tons, so if there are many airplanes lots of cable can be carried. From highest flying plane cable goes to rocket. Highest plane can be jet fighter flying close to mach 3 in high altitude and carrying 15 tons of cable, with minimal fuel reserves for the plane. Airplanes carry cable weight, and from cable spacecraft gets electric power up to 12 - 20 km height perhaps. Perhaps jet fighter aircraft can carry cable near 30 km high. In high altitude cable is disconnected and only first stage of spacecraft uses electric power, or electric cable extends to 50 km high or even to space. Other stages of spacecraft, when electric cable ends, use some other power source, chemical rocket etc.
If big rocket like BFR that weights 5000 tons uses electric power in first stage of rocket, savings are enormous. Similar electrically powered propulsion that “Beamed propulsion” spacecrafts use or “magnetohydrodynamic drive”. “Electrically powered spacecraft”.
Also helium or steam balloons can be used to carry electric cable.
If plane flies higher than spacecraft that is ascending, cable can be hanging downwards to rocket from plane, so not much weight for spacecraft because of the cable, when spacecraft reaches plane s altitude plane lets cable loose and higher flying plane holds cable then. Only when highest flying plane lets cable loose and spacecraft flies higher than it, then cable starts to get heavy and gets heavier the more spacecraft rises upwards and needs more cable from feeding system that feeds cable perhaps several kilometres per second speed. Freight aircraft can carry 120 tons or in case of An 225, 250 tons, so feeding system can be in the plane. Jet fighter carrying cable perhaps also needs feeding system or it just is a cable carrier.
Instead of electric cable planes can be used to carry fuel tube for spacecraft that is fueled in flight, it flies with empty tanks to altitude because its rocket motors use fuel from the ground and near disconnection altitude of fuel tubes rocket tanks are pumped full.
This rocket fuel can be water. Water can be made to hydrogen peroxide using some sort of sieve according to “In totally unexpected finding, water has spontaneously produced hydrogen peroxide”. Not all water is needed to turn to hydrogen peroxide, some mix of water and hydrogen peroxide will do, water can also be used as fuel in ALICE rocket engine. Or water can be decomposed to hydrogen and oxygen, “water splitting”, using electrolysis or thermochemical reaction etc. The heat of thermochemical reaction of water splitting can be used in rocket engine.
When hydrogen and oxygen from water is made in the rocket and burned as propulsion fuel, it is water again, this water vapor can be used as fuel in ALICE rocket engine, so this is “double burning” principle where burning products of one fuel are used as fuel again with another fuel and burned again. Two chambers are needed in rocket engine for “double burn” rocket engine or only “afterburner” principle is used where in rocket nozzle this second additional burning happens.
If electrolysis is used there are powerful chemical electric power sources that electric torpedoes use, torpedo batteries have high temperature chemical reaction that sometimes burn through torpedo casing, but this heat can be used in rocket, rocket fuel can cool hot battery like fuel cools rocket nozzles, so chemical torpedo batteries can have even higher temperature without melting. These extremely high temperature batteries based on torpedo batteries can be used in rocket for water splitting. Or rocket uses some other water splitting method.
Also if water can be made to hydrogen peroxide in simple way, ships, trains and cars can use water as fuel, water is turned to hydrogen peroxide in some fuel plant, or in ship or rain or car has system that turns water to hydrogen peroxide. Hydrogen peroxide is this “water fuel”. And if only water is poured to fuel tank and it becomes inside vehicle hydrogen peroxide, also “turbosteamer” principle can be used in ships, trains and cars, where cooling water of engine is turned to steam and this makes extra power for engine. Diesel engines in ships can use “water fuel emulsion”, they can have machinery in ship that makes diesel fuel / water fuel emulsion blend, and so save fuel. They can use turbosteamer principle too. Ships can then use water as fuel. In Robin Hood Coop forums are texts “Using water as fuel”, “Forgotten innovations of gasoline engines”, and “Modern biofuel/woodgas generator”.
Plans for rocket / spaceplane in flight refueling are forum nasa spaceflight com : “Suborbital refueling of a rocketplane”, “Aircraft launch complex for transportation, refueling and launch air rocket” (1300 ton payload airplane), “Black Horse: one stop to orbit”, “Self-refueling rocket propulsion for future space travel” 1985, and “Suborbital refueling: a path not taken”. But all those plans use carrying fuel with airplane or spaceplane, but fuel can be just pumped from ground to spacecraft using fuel tube. This fuel can be some safe fuel like energetic ionic liquid based, monopropellant, bipropellant or tripropellant, or just water that is turned to fuel in spacecraft itself, or water with some other safe liquid and this water/liquid bipropellant is rocket fuel, or only safe fuel or safe oxidiser pumped to rocket in flight, rocket has another part of bipropellant (oxidiser or fuel) in its own tanks, like ALICE rocket where water is pumped from ground. Double burn rocket engine principle can be used with in flight refueling / fueling from ground using tubes. Airplanes can also carry fuel, not just fuel tubes, An 225 can have 250 ton load so 250 tons can be air fueled through fuel tubes or in other way to for example 500 ton rocket that gets 250 tons of fuel through air fueling.
Or using electrical power to propel rocket, then just electric cable must be connected to rocket and electric power comes from ground.
Hydrogen peroxide can be used with ethanolamine catalyst for 245 m/s specific impulse monopropellant, with nitromethane / hydrogen peroxide blend for 300 m/s (?), with hydrogen / hydrogen peroxide mix for 380 m/s impulse, with DMAZ / hydrogen peroxide mix 360 m/s. Quora netpage: “Could rocket burn liquid hydrogen and hydrogen peroxide?”.
Electric cable that powers spacecraft can be used as “electric tether propulsion” generating even more electric power for spacecraft. Power of thunderstorms can be used to electric spacecraft propulsion.
“Forget rocket fuel: this spaceplane will use microwave”. But microwaves (or lasers) are not needed if just electric cable goes to spacecraft.

Perhaps best way for making electrically powered rocket is that there is rocket and then rocketplane that is “cable carrier”, this cable carrier rocketplane is like IAR 111 or something like that, it has not enough speed to rise to orbit, it just flies to high altitude and then drops back to earth, its job is to carry electric cable of rocket proper so that rocket itself does not have to carry cable that extends to space. Some amount of cable must rocket carry as weight, that small amount that goes from cable carrier rocketplane to rocket proper. But rocketplane carry cable from low altitude, where it is perhaps carried by cargo aircraft, to near space. Cable weight can be perhaps 100 ton or higher, so this additional “cable carrier” rocketplane makes possible that rocket itself can have 100 ton or more additional payload. Flight paths of cable carrier rocketplane and rocket itself are designed so that minimal amount of cable goes from rocketplane to rocket.
Rocketplane “cable carrier” must be capable of high supersonic speed so it is more like big X-15 aircraft than slow supersonic IAR 111. If cable carrier must carry 100 ton or more cable, it is then much bigger than X-15, but perhaps this rocketplane has quite similar flight performance specs that X-15 had. Whatever is needed to make assistant rocketplane to carry electric rocket that is launched to space, and this rocketplane that cannot follow rocket to orbit must follow rocket s flightpath at some distance, more closer the rocket the better, and cable carrier must also at some extent keep in pace with rocket so rocketplane needs speed also, but not as much speed than rocket if flight paths of both rocketplane and rocket are designed carefully, so they have slightly different flight paths and different speed but still during flight path stay relatively close to each other. Rocketplane must take lift off before rocket and rocketplane is already in altitude gaining speed when rocket starts and then rocket passes it by in altitude etc. Electric cable connects cable carrier rocketplane and rocket proper, from rocketplane cable goes to ground from where energy for rocket comes. Heat protection also is needed when it falls back to earth because it has no orbital speed, or it flies just in atmosphere, 60 - 100 km high, and rocket uses another propulsion method than electric from 60 - 100 km upwards. “Electric” means here something similar that “beamed power” spacecrafts use to get to space, and “MHD propulsion” etc. electric propulsion methods that can lift heavy loads.
There is another superconductive material class, hot superconductors, not only low temperature and high temperature superconductors. Those hot superconductors have superconductivity in over 200 C temperatures. “Superconductors org / news” netpage. Those hot superconductors are suitable for superconductive electric wire of electrically powered rocket. Also electric superconductive cable does not need ordinary cable backup system that superconductive cables usually have, if cable superconductivity quenches rocket uses same propulsion system what rocket uses when in orbit, to give speed to either make emergency landing or continue to space if superconductivity quenches.
Also if in low altitude is air drag, making rocket aerodynamic helps. Rocket can have long aerodynamic spike that those test aircrafts have that use that spike for low noise supersonic flight, if that spike makes aerodynamic drag lower. “Aerodynamic airspike”. Also electric rocket can use electric arch in front of spacecraft to minimize drag. Payload fairing can be aerodynamic long like missile warhead.
Electrically powered rocket when it disconnects its electric cable has another propulsion system that it uses in orbit, VASIMR, nuclear rocket, chemical rocket etc.
Rocket sled that uses additional rocket stage that comes down to launch pad, needs only rails that are like railway rails, that rise 600 m vertically upwards. When additional rocket booster stage comes back to launch pad airbag style system can be used in landing, before rocket stage hits ground airbag in launchpad is filled with air or gas and rocket stage lands on this airbag.
If some high plateu is used to launch space rockets, and there is very few roads, railroads can be used, rocket is packed in railway transporter ejector launcher. Or rivers can be used, rocket is in barge that is towed to launch site. “Launch site” is the river, in launch rocket rises from barge using ejector system and is launched from barge. In 6000 m high Pamir plateu or in other high place. Wheeled / tracked transporter ejector launchers can crawl with light space rocket to mountaintops.
High accelerating space rocket that for example use hydraulic lift from high dam or waterfall can be shaped like artillery shell, or like russian N 1 rocket, conical shape. Rocket can accelerate perhaps 80 g / 800 m/s, even 5000 ton weighting rocket using height distance and hydraulic lift (mass of water from high place - man made dam, natural dam or waterfall). In previous posts was that ASAT system had 80 g acceleration but that was Sprint missile system, and that was ABM missile, and it had 100 g acceleration.
In India is solid rocket boosters that vary from very big (S 200) to small. Buying those solid boosters and building rocket upper stages on top of that, using cheap first stage solid rocket from India perhaps can make cheap space rocket. India is making “Universal launch vehicle” with many different size rocket boosters so there will be many different weight and power ratio solid boosters available from India.

In previous post was indian “Universal launch vehicle”, that meant “Unified launch vehicle” that has several different size solid rocket boosters from 12 - 13 tons to 200 ton size.
Electricically powered rocket that has enough power to lift payload from ground to space needs some propulsion material, hydrogen has been proposed, to make it plasma etc. There is also “solar powered rocket” concept. But no big lens floating in space or atmosphere that focus sunlight to rocket, and no microwaves or lasers are needed to power rocket from outside, just electric power is needed. So only long (superconductive) electric wire is needed. ARCAspace is even building water-electric rocket. Both water and electricity can be pumped to rocket from ground, at least in first stage of multistage rocket. Electric wire can extend to space if additional “cable carrier” rocketplane carries most of it so rocket proper does not have to.
Also “Electrical driven cellular structure accelerative propulsion engine EDSCAPE” has been mentioned in one internet post in Quora netpage about electric rocket (“Why isn t an electric rocket engine possible?”).
Engines that use air, air turborocket, RTR turborocket, SABRE, and “Fenris engine” has been proposed. Also electric propulsion can be used in jet engines: “Fossil-fuel free jet propulsion with air plasma”, “Plasma jet engines that could take you to…” If air can be turned to plasma using electricity then some other propellant than air can be used in high altitudes where is no air and this plasma - jet can be used as spacecraft propulsion. Those plasma jets have power of ordinary jet engine so much powerful than ordinary electric-plasma methods used in satellites, perhaps magnetohydrodynamic engine has high power also. Electric power is needed and then propulsion mass (for plasma) in electrically powered rocket. Very high specific impulse is then possible. Also “Propulsion plasmique Safron aircraft engines”, “Momentus water plasma propulsion”, “Perspectives, frontiers, and new horizons for plasma-based space propulsion”.
Also new rocket fuels have been invented for chemical rockets: Adranos rocket fuel (ALITEC), and “TSU physicists have created one of most efficient rocket fuels”. Adranos rocket has fuel that has up to 65% higher payload capacity than ordinary solid propellants. That means that solid fuel is more powerful than hydrogen/oxygen? If that is is true it means that all chemical rockets made today are outdated if solid fuel can outperform any liquid fuel. Saturn rocket program had very large solid rocket booster in prototype form. Solid fuel can also be made more effective using CL-20 or other additives. The another fuel is boron based solid, but it is used in hybrid rocket? With oxygen as oxidiser? It is developed to be used in indian rockets. The Meteor ducted rocket missile is using boron fuel. If such system can be upscaled to ducted space rocket first stage? Using both new effective boron fuel and ducted rocket. First stage can use ducted engine, other stages liquid oxygen.
Also nanofuels, or nanoparticles in ordinary rocket fuel, solid or liquid, has been studied. Nanofuels can be used themselves as rocket fuel, or just particle additive in ordinary fuels.
In phys org / news netpages is rocket propulsion related articles: “Study tests performance of electric solid propellant”, etc.
Other: “Study models new method to accelerate nanoparticles”, “Parallel residual projection PRP”, “Shockwaves might offer the jolt needed to reach Mars”. “Making a zero emission fuel even more effective”, it has hydrogen - nitrogen - air (oxygen) mix? If hydrogen and oxygen are used as rocket fuel then the nitrogen can be pumped from the ground. “Nanofuel as potential secondary energy carrier”, water is mixed with nanofuel particles and used as fuel, then water with nanoparticles can be used as rocket fuel also? So very high amount of water mixed with little amount of nanoparticles is needed to make rocket propulsion? Only small amount of nanoparticles is then needed in rocket, water is pumped from ground. “Appearance of a micro-launch system meant for launching rocket…”, “Utilizing nanotechnology in aerospace and rocket fuels”.
“New nanoparticle can turn carbon emissions into fuel”, if that can turn burning products like carbon monoxide, dioxide etc. to fuel, perhaps similar system can be used in rocket to turn burning products of one fuel to fuel again, and then burned again, using “double burn” principle?
“Enhancement of liquid fuels via nanoparticles”, “increased act-plate ignition probability for nanoparticle…” etc.
If high explosives are used as rocket propulsion, and HE rods are shot to rocket nozzle where they explode, but this HE rod has such great speed when it enters rocket nozzle that when HE burns fast (explodes) explosion stays in the nozzle. Instead of ordinary gun propellants used in “gun” inside rocket that fires those HE rods to rocket nozzle, light gas gun, coilgun, railgun or ram accelerator can be used, so that HE rod has several km/sec speed when it enters rocket nozzle, or near to 10 km/sec speed so explosion velocity of gases that has almost 10 km/sec speed have additional 10 km/sec speed from “gun”, so combined speed of exhaust gases from explosion is 20 km/sec, force of explosion(s) pushes rocket to space. Rapid firing rate is used so that almost constant thrust is achieved. If high explosives when they explode make more specific impulse than ordinary rocket propellants that just burn. Even small pellets of (almost ordinary) solid rocket propellant can be shot using “gun” inside rocket to rocket nozzle where those pellets burn (almost) like ordinary solid rocket fuel but have also additional speed that gun gives to them, so when solid fuel turns to burning gas that gas has additional velocity too. Or if fuel is liquid this liquid is pumped to high speed and when this fuel burns it retains that high speed and velocity of burning gases of fuel also, so those velocities are combined and so rocket exhaust gases have greater speed than just burning gases alone.

In previous post was that Adranos rocket and its ALITEC fuel could be more powerful than liquid rocket fuels. But I don t know how to calculate specific impulse, rocket equation etc., and actually 65% more payload in solid rocket is not so much specific impulse increase when solid and liquid fuel rockets are compared? I cannot calculate those diffrences so I don t know. But if specific impulse is relative to weight of rocket, not weight of payload, then 65% increase of payload is not much increase in total rocket weight, so although solid rocket can then lift heavier payloads it is still much less in performance compared to liquid fuel rockets? Perhaps additive like CL-20 added this rocket fuel can be in par with kerosene/oxygen? But not even near to hydrogen/oxygen in efficiency? I cannot calculate those things.
The problem with solid fuel rocket stage is that recovery and reuse of it is difficult, because if it lands back to earth some throttling system is needed and some extra fuel before it lands to ground, like SpaceX recovers its rockets. Perhaps some simple and small additional storable liquid fuel or solid fuel rockets can be added to rocket stage and those smaller rockets fire just before rocket stage hits the ground so landing is soft. Perhaps then also solid rocket stage can be recovered and reused? Landing in water like Space Shuttle boosters used is possible also, but cleaning those rockets that landed in water was more costly than building new rockets. If that solid rocket stage is used in non-reusable form, those small side rockets are simply removed. So if solid rocket has about same performance (specific impulse etc.) than kerosene/oxygen rocket stage, it is cheaper to build and use solid rocket instead of liquid rocket? Ariane 5 solid boosters are recovered from sea (?) like space shuttle boosters. If not whole rocket stage is recovered, telemetry systems, computers etc. from rocket stage can be recovered still, all in one module that is dropped from rocket and then uses parachute etc. There are plans that just rocket motors, not whole rocket stage, can be recovered, in liquid rockets, because rocket engines are most expensive part of rocket stage. Even Space Shuttle had plans to turn shuttle to unmanned cargo vehicle and only shuttle engines would go back to earth, not unmanned payload compartment.
It is possible to use hybrid rocket that uses liquid oxygen (?) and solid propellant, then rocket can be throttled and restarted when needed etc., so controlled landing and recovery of rocket stage is then easier than recovery of plain solid rocket. If rocket is air breathing (ducted rocket etc.) flying rocket back to earth is fairly easy, if it has small wings.
If rocket uses electric power and electric superconductive wire that extends to 150 - 200 km or more length, this superconductive wire can be cooled to low temperature before it is used to transfer electricity to rocket. Cooled to low temperature, and when its temperature rises when it is used as electric cable that brings power to rocket, just before its temperature reaches so high that superconductivity quenches wire reaches its maximum length and rocket disconnects wire and goes to orbit. In orbit or even before it reaches orbit rocket uses some other propulsion system than electric/thermal propulsion (or whatever electric propulsion methods there are that can lift heavy loads with some propulsion mass that is turned to plasma etc.).
If big rockets use 40% of their fuel to accelerate to 450 m/s speed, then additional booster rockets that fast accelerate rocket to 450 m/s speed are needed. About 4 or 5 g acceleration (40 m/s and 50 m/s) is only few seconds time and then rocket is in 450 m/s speed and from there accelerates slowly with almost full fuel tanks. But in start and few seconds after that (solid?) boosters that accelerate rocket to 450 m/s are needed. If rocket is big and its first stage accelerates slowly (Saturn 5, BFR rocket). BFR weights 4400 - 5000 tons, so if additional boosters are added it weights even more. But those boosters burn only very limited time and then they are discarded, so not so heavy after all? If those additional boosters save 40% of fuel of rocket proper, this saved fuel weight can be used as payload weight? 40% fuel saving means then about 2000 ton payload capacity in BFR rocket, not 180 ton capacity like BFR without accelerator boosters. 2000 ton payload to low earth orbit is huge improvement compared to just 180 ton payload. This 2000 ton payload increases rocket weight even more still, but advantages are enormous in payload capacity, then BFR would truly be “Spaceship”. If that 40% fuel saving weight can really be turned to payload weight.

If boron or boron based rocket fuels have most specific impulse after hydrogen, boron rocket fuels can be made. If boron burns too slowly, it can be mixed with other fuels or oxidizers. Kerosene is next best behind hydrogen and boron. Kerosene is refined paraffin. Paraffin is solid hydrocarbon. Kerosene burns fast. So highly refined oil-based solid rocket fuel, like some “solid version of RP-1”, does not burn like solid fuel but explodes if it is tried as solid rocket propellant? So why not combine slowly burning boron and fast burning oil-based solid propellant, and result is something like coal material, “rocket coal”, that rockets can use as propellant. Boron and highly refined oil (solid) mixture, with solid oxidizer and additives, binders, energizing particles, aluminum etc. in same rocket coal mixture. Solid monopropellant, or bipropellant that has separate fuel and oxidizer, both in solid (powder) form. Or oxygen or other liquid as oxidizer and rocket coal is just fuel without oxidizer, so rocket is then hybrid rocket. Solid propellant is dense, denser than liquid. Solid rockets are cheaper than liquid rockets. So “rocket coal” rocket combines cheap manufacturing of rocket and fuel that is more energetic than RP1, and fuel is denser than liquid fuel so more efficient that way also. Higher payload than conventional rockets and cheaper at same time, if oxidiser/fuel combination of “rocket coal” is more efficient than RP1/liquid oxygen.
To control burning characteristics similar additives, energizing additives, binders etc. that solid rockets use can be used in rocket coal also to control burning. More boron this rocket coal contains and less refined oil the better, because boron has more energy.
Similar slush fuel (mixture of liquid and solid fuel) that ALICE rocket propellant is, can be made from oil based (RP-1) liquid and boron mixture. And similar cryogenic method (cooling of propellant) can be used to make it more stable. Solid fuel that is not slush can be cooled also if it needs to, to prevent some self ignition or to control fuel / oxidizer. Then whole rocket must be cooled because solid fuel is inside rocket casing.
It is proposed that shoulder launched anti aircraft missiles can use rocket propellant that contain up to 35% of HMX. That kind of fuel is so unsafe that it is not used in other military missiles, not even aircraft air to air missiles because they can explode if put under airplane wing because of vibration etc. However this rocket fuel is most powerful solid (?). Civilian space rockets use safer fuels. But light space rockets, that “new space” firms use, that lift small payloads, even as small as 5 kg, and 15 kg, and 50 kg to space, need efficient and cheap rocket. Those payload satellites are cheap and cubesat - type at lightest. So loss of small and cheap satellite (5- 50 kg) is perhaps acceptable sometimes. So those small rockets can use that very powerful rocket fuel, and perhaps make even more powerful propellant, that makes rocket stage explode about 20% - 30% propability. If three stage rocket has first stage with this explosive propellant and two other stages similar efficient propellant that is proposed to shoulder launched AA missiles, fast burning time of rocket first stage (compared to all three stages together) makes explosion probability small, and if rocket accelerates fast, 20 g or more, burning time is so short that critical pressure / temperature probability is less rocket stage to explode. Making rocket casing of composite material and withstanding high pressures high energy solid propellant can be used. Four stage rocket can have two first stages using this explosive propellant, if rocket burn time is divided between two stages, probability of explosion can be perhaps lessened.
Bigger rockets, that can launch 100 kg to 1000 kg loads to space, can use that proposed AA missile fuel, if it is safe enough for man portable rocket it is safe for satellite launches also. But it is expected that failure rate is greater than in other rocket types. Perhaps in satellites over 1000 kg or 2000 kg risk of failure is too big because those satellites are expensive, but in lighter satellites effective solid fuel can be used, with risk. CL-20 can be used also if its better than HMX (but HMX produces more gas when it is burned so better?).
Energizing particles can be added to solid propellants (RNX, RDX, ADN, ADNAZ, TNAZ, BTTN, TMETN, TEGDN, BDNPA/F). To have solid propellant maximum amount of energy perhaps all energizing additives can be added together, so that chemical reactions that make solid fuel explode if there is too much additive, does not explode if there is several energizing additives, with different chemical reactions, so more energizing additives can be used safely because none of those chemical reactions reach critical level, instead of large amount of one energizing additive. Large number of small amount of several chemical energizing additives.
ADN, HAN, HNF, GAP and MOF (metal oxide framework) are rocket propellants also. Metal fuels that can be added to for example “rocket coal”, are aluminum, magnesium, zinc, boron, tungsten, zirconium, copper, chromium, molybdenium. “Propellants based on CL-20 can match performance of NTO/UDMH”.
Other powerful solid propellants have been studied, “petrovskite high energetic materials”, “carbonyl diazide”, “High density assembly of energetic materials under the constraint of 2D materials”, “(borane) hypophospate-based solid liquid as ultra fast…”, “New rocket fuel? Solid nitrogen”.
“New MOF material captures and converts NO2”, “Magnesium and carbon dioxide: a rocket propellant for Mars missions”. Those two can perhaps be used as double burn principle where burning products of some propellant are used as propellant again and burned again.
Also gelled fuels, like perhaps gelled RP-1, can be used as solid fuel. Perhaps some sort of gelled oxidiser, even gelled oxygen rich material, “gelled oxygen”, can be made and used as solid propellant.
Scitoys com netpage: “High performance rocket fuels”.

Some mistakes in previous post are now (hopefully) corrected.
"Pulsed rocket motor and “dual thrust” are methods of segmented solid rocket motor where propellant is separated in segments that burn separately to each other. So then highly energetic solid propellant can be put to small capsules with diameter of rocket casing, or even diameter of rocket casing is separated to small capsules, so both in height and diameter of rocket casing is separated bu small burning capsules, and although they burn highly energetic they don t explode the rocket because they are in those thin but wide capsules that burn fast, perhaps fractions of second so their pressure or thermal properties do not reach explosive level. When one capsule is burned second starts burning and so on until all those capsules stacked on top of each other (or also side by side in rocket casing) have burned. Capsules that are side by side in rocket casing can burn at same time. But anyway when one layer of those stacked capsules is burned in stack layer of capsules on top of them starts burning etc. until they have burned from bottom to top inside rocket casing. There can be thousands of small those thin but wide capsules inside rocket casing. This to prevent explosion of highly energetic fuel. Or another way is that those capsules really explode, propellant is so energetic, but in underside of capsule is vacuum so rocket propellant explodes downwards, and after explosion of that capsule, another capsule is top of that in stacked arrangement, it then explodes, and vacuum directs explosion energy downwards, to rocket thrust, and so on until all capsules have exploded. This is pulsed propulsion using explosives. So highly energetic explosive rocket propellant can be used.
Meteor missile uses boron propellant, making space rocket upscaling Meteor to hundreds of tons weight, and it has then three stages and first stage, or second stage, or both first and second stages use ducted rocket motor, so air as oxidiser. First stage can fly back to earth if it has wings, second stage perhaps also (?), or it is non-reusable, and thirds stage is normal rocket stage, but it can use boron as fuel too perhaps.
Vertical rocket sled can be used to propel rocket to speed that makes ducted rocket motor working, or if rocket is smaller JATO bottles can be used that have small parachutes and can be recovered.
Also commercial jet engines can be used to lift rocket from the ground. The most powerful bypass turbofan used in commercial passenger planes has high power. Military jet engines that can have mach 2 - mach 3 speed and it can be used carrying lighter rockets. Perhaps vertical rocket sled or JATO bottles are again needed to lift jet engine/rocket combination to speed near mach 1 (340 m/s), then jet engines need only maintain that speed, not to accelerate, or even slowly slowdown combined jet carrier/rocket speed. Large number of bypass jet engines can be used, 5 to 7 around rocket hull. Smaller military mach 2-3 engines can be grouped more than 7 around rocket
Jet engines use afterburner and before used water injection. In high altitude is not oxygen so much, so afterburner is not so good then? If jet engine uses water injection in high altitude it is better than afterburner? Or in high altitude both afterburner and water injection can be used. So that jet carrier can lift rocket to high.
Also bypass turbofan modified to rocket carrier can have added afterburner and water injection, both of them. Afterburner like military jet, in commercial passengerplane bypass turbofan with high bypass ratio. And also water injection included.
This “rocket carrier”, that is perhaps launched using vertical rocket sled or additional solid booster stage(s), when it is freed from booster or vertical rocket sled it is not going straight upwards but slightly steep rise, perhaps 70 - 50 degree angle, so both airflow to engines and power requirements are eased. In high altitude rocket carrier jet has perhaps 40 - 45 degree upward course just before it launches rocket. Rocket carrier that has jet engines can have wings that help it to get lift and also with wings this carriers lands back to earth. But it is not airplane, it is something between rocket and airplane. It is not same kind of airplane that is used in air launch to orbit scenarios, it is just structure with jet engines around rocket and perhaps bottom of rocket and it has wings. If it has big wings then engines can be in wings and not around rocket. It has fuel just enough to rise the rocket and then go back to earth, with minimal fuel reserves. Perhaps rockets own engines are used also during liftoff and rise, so then rocket rises vertically upwards and those jet engines are used like rocket boosters, but instead of solid rocket booster, boosters are jet engines.
This jet (and /or vertical rocket sled) rocket carrier can carry different rockets, with different weighs. This rocket carrier service can be sold to many different rocket firms, their rockets can then have additional boost and payload is bigger.
Also balloon launch of rockets can be sold to different “new space” firms that have small rockets, launching cubesats etc. So different new space firms can use same balloon launch service, their rockets then can have bigger payload. Either helium or steam balloons can be used, or even hydrogen balloon lifting heavy rocket.
Boron has difficulties as rocket fuel, it burns slowly? But if it is mixed with energetic propellants, perhaps with another metal in solid fuel, aluminum, magnesium, lithium, zirconium, iron (?), this mix of two or more metals then burns better? Sprint missile used nitroglycerin, nitrocellulose and zirconium metal chips. CL-20 can replace nitroglycerin in rocket propellants?
Usually military uses in missiles unsafe propellants, and civilian space rockets safer propellants, but in small and cheap rockets, and in perhaps bigger rockets too, that are in small launch vehicle (max 4000 kg payload) range, unsafe but energetic propellants can be used. Propellant(s) that are unsafe and in danger to explode can be used (with boron?), to make highly powerful solid rocket. It can have bigger specific impulse than kerosene/hydrogen. Perhaps more than hydrogen/oxygen. Perhaps special safety procedures must be used, all vibrations must be minimized when rocket stages are made and transported, so rocket propellant does not explode, launch pad can be expendable (if it is danger that rocket explodes in launch pad), launch preparation is automated with very few people needed in launch pad, and those people that are handling rocket at its manufacturing stage, transportation and launch can wear same protective suits that people who dismantle bombs use. There is higher risk of failure in each launch, more than in normal rocket launch, but it has much higher payload than rocket of same size that uses ordinary propellants.
This unsafe rocket propellant can be cooled to very low temperature, like liquid hydrogen temperature, to keep it safe. Nitroglycerin is safe in low temperature, same principle can be used with other unsafe propellants. Then propellant must be powder or liquid and in monopropellant or bipropellant (powder bipropellant or monopropellant) or tripropellant. “New rocket propellant and motor design offer high performance and safety”. Solid cold unsafe powder goes to rocket chamber or nozzle and is burned there. CL-20 can be mixed with HMX and this mixture is relatively stable? Desensitizing additives can be used with propellant to keep it not to exploding. Perhaps some “super explosive” can then be tamed to be used as rocket propellant.
“High density fuels, boron-gel fuels and diboride thermal protection systems” (Lorrey Aerospace).
Nothing to do with rockets, but another fuel matters: “Oleg V. Gritskevitch: hydro-magnetic generator” (hydro-magnetic dynamo) 2001, and advancedbiofuels usa netpage “Are you aware of a game changing fuel”.
Rocketplane that carries superconductive electric wire for electro-thermal space rocket, can have cooling system that keeps superconductive wire cool inside rocketplane. Perhaps over km/sec speed wire feeding system is needed, so perhaps quasiturbine can power wire feeding system, or fuel or water pumping system if water or fuel is pumped to rocket in flight, or in ground quasiturbine can give power to vertical rocket sled. Heavy rockets if they are not launched using additional booster stage as vertical rocked sled, but use some mechanical “elevator” in vertical rocked sled, if rocket sled is in side of almost vertical mountainside, then (almost) vertical rocket sled can be build using mountainside as base which supports (almost) vertical rocked sled. Now even heavy rockets can be launched almost upwards from (almost) vertical rocked sled, using elevator principle, mechanical power from electric motors or diesel motors, quasiturbines etc that propel rocket during liftoff until almost vertical mountainside ends. Rockets own engines can be used at same time when rocket rises using (almost) vertical rocket sled, to give more acceleration.
From nasa spaceflight com netpage: “Is it possible a super fuel may be discovered or made”: monoatomic hydrogen, metastable polymer nitrogen, spin-polarized triplet helium, diatomic metastable helium. If some super rocket propellant has only 2,3 hour time before it dissolves, then this propellant is made at near launch site, pumped immediately after it is made to rocket, and rocket is launched before propellant dissolves.
“Solid-amine boranes as high-performance rocket fuels”.
Russian patent RU135000U1: “Hydrocarbon rectangular engine”.
“Highly powerful new biofuel could change rocket engines forever” (pinene).
Biofueldigest: “9 advanced molecules that could revolutionize…”
From netpage defense pk: “China has developed new generation powder that is 100 X more powerful than TNT”. It is some form of nitrogen? Solid nitrogen was studied as rocket fuel in the west (netpage “New rocket fuel?: Nature news” 2002).