New Mars Forums

Well, when we started talking about it, let me describe in details, how my spaceplane is presumed to fly into space.

Take off from a regular runway, on four turbojet engines of the first stage (the two - fuselage tandem airframe, mounted under the big wing of the second stage, which you could see on the drawings). For additional acceleration during takeoff, the rocket engine of the third stage could be also employed, for a short time; but this would burn rocket fuel needed when we'd climb higher, and so I don't like this possibility, this is just to mention.

Four turbojets of the first stage climb the system to altitude about 20 - 25 km, and velocity about М2.3 - М2.5. On this altitude and velocity, ramjets of the second stage are ignited (more precisely, this altitude and velocity is dependent on the characteristics of ramjets: on which minimal velocity and altitude they are able to ignite, provided we're trying to specialize them for maximal velocities and altitudes). During some time, when thrust from ramjets is not very high yet, the system could accelerate with turbojets and ramjets, working simultaneously; moreover, it would be even possible to implement a pass-through for fuel from first stage to the second one, so when ramjets are burning with first stage attached, they are fed by fuel from tanks of the first stage.

Then, it's time to separate the first stage; I know, it could be the problem, but it surely could be solved. For example, if thrust of turbojets of the first stage would be slightly stronger than thrust of ramjets of the second stage, the first stage could move slightly forward (no obstacles there due to geometry); and as wing load per square of the first stage is significantly stronger as compared to wing load per square of the second stage (because wings of the first stage are so small), the first stage would also move slightly down. That way, the stages could safely separate (I know, some problems could also appear due to Bernoulli effect between aerodynamical planes of first and second stages, and supersonic shock waves, etc.; but it all surely can be sorted out, we just need to work upon it, for example trying to work out separation of stages on small flying RC models).

After the first stage is separated, the two rear vertical stabilizers are unnfolded (as shown on the drawings), and the stage fly on it's own small wings to the  runway (still using it's turbojets, or maybe even gliding). Ramjets of the second stage climb the system to altitude about 50 - 60 km, and velocity about M5 - M6. We need to specialize the ramjets to work on maximal altitudes; it's also possible to inject on high altitudes some liguid oxidizer in burning chambers of ramjets (so they would still burn even on very high altitudes - this is not my idea); but nevertheless, on very high altitudes their thrust became weaker. So, on some moment, a rocket engine of the third stage is ignited, fed by fuel and oxidizer from the second stage (the second stage plays a role of external fuel tank). For some time, weaking ramjets are working together with rocket engine. Than, ramjets are shot down, and the system climbs into space on the rocket engine of the third stage, fed by fuel from the second stage (geometrically, we could store a lot of fuel there).

Having burned all the fuel/oxidizer from second stage, the system reach on altitude of about 100 km, or even higher (nearest space, out of atmosphere), with horizontal velocity about 1.5 km/sec. There, the second and the third stages are separated (no atmosphere, no problem with separation). Than, the second stage fly down, glide and land on the runway; when the third stage, full of fuel/oxidizer, obtain with it's rocket engine these additional 6.5 km/sec, reaching low Earth orbit.

It's worth to mention: we really could see the second stage (the big wing) as an external fuel tank. The matter is, it could be done very light (with very good mass efficiency). The mass of ramjets, themselves, could also be low; at the contrary to turbojets, there are nothing to be heavy in ramjets (no compressor, no turbine). The big fat wing of the second stage could be done in a way, that it keeps itself strong just by internal pressure, like inflatable toy (of course, there is some art in making it's internal fuel/oxidizer tanks, so they would keep the aerodynamical form of that big wing just by internal pressure; but that could be done). Also, this (nearly inflatable) wing could have a sharp leading edge attached, and this leading edge could be cooled by flow of fuel/oxidizer, pumped through the internal channels of the edge before using.

Being so light, the second stage needs no heat protection (maybe, it only should be done from heat-proof materials: hot frame), gliding through atmosphere to land on a runway. On the contrary, the third stage (spaceship) would need heat protection; although not so thick as the Shuttle or Buran had, because of much less wing load per square.

It seems to be all; but, as far as we started the techical talks, I'll try to explain my invention of multiple and multistaged refuelings, and all the other things, concerning interplanetary flights on completely reusable spaceships.

And so, the third stage of the spaceplane (spaceship) is flying around the Earth, on LEO, with (nearly) empty fuel tanks. Let's imagine, what if we don't load any cargo to some another similar spaceship, and launch it to orbit, somewhere nearly by the first one? As there is no cargo loaded, it'll arrive with some rest of fuel/oxidizer in its tanks. What if we dock these spaceships together, and transfer this small rest of fuel/oxydizer into tanks of the first one (of course, docking devices should be provided)?

Ok, transferring of fuel/oxidizer is over, spaceships undocked, and the second one is going to land. Let's launch yet another spaceship without cargo, so it transfer the small rest of fuel/oxidizer into tanks of the first spaceship, than undock and land. And so on, and on, and on - let's launch new and new spaceships without cargo one after another (or only one - but launch it many times), so they'll dock to the first spaceship with small rest of fuel/oxidizer, than transfer the fuel/oxidizer into its tanks, than undock and land (for simplification, I'll sometimes say "fuel", meaning "fuel/oxidizer").

It's easy to see, that we could repeat such a procedure, until we end up with fuel/oxidizer tanks of the first spaceship completely full. This is especially convenient exactly with completely reusable spaceplanes: because of their minimal cost per launch. (In fact, all elements of my spaceplane are reusable for hundred and thousand times, nearly like an aircraft; the only exception is the rocket engine of the third stage: it also could be reusable, but it's working lifetime probably would be much smaller, so we'll need to provide a possibility to easily change the worn-out engine by the new one).

And so, after a few (about 10 - 15, depending on mass efficiency) additional refueling launches, we could have the third stage (spaceship) completely refuelled on LEO. It makes possible bringing the cargo on high orbit, or even flying around the Moon. But again, what if our spaceship just moved on high circular orbit, using some fuel? Couldn't we completely refuel it there? Of course yes: we just need to launch one other spaceship, that would accumulate fuel on LEO from arriving spacepllanes, and than brought it to high orbit, using some fuel for that. And so on, and on, and on: in that way, we could fly to every possible highest Earth orbit, including geostationary. And also we could fly to Moon, came up to Moon orbit, and return to LEO.

At that, we see, most of times the spaceships would carry not a payload, but the fuel/oxidizer; and it would be good to implement specialized spaceship (the third stage) to carry only fuel/oxidizer. Of course, the fuel/oxidizer should be carried in the same tanks that are used for feeding engines (no need to divide them); but, because specialized tanker spaceship will return to Earth always empty, and because there should be no cargo bay between fuel and oxidizer tanks, the tanker could be done lighter, with smaller wings and less heat protection; so it would be more mass - effective, as compared with the general cargo (or passenger) spaceship (and this is the very reason, why it's profitable to implement the reusable tanker: in fact, every spaceship could be used as tanker, it's only less mass - effective). 

Also, as we could see, sometimes we'll use some tankers in space without need to return them to Earth: for example, to routinely carry fuel from low orbit to high orbit, an then return to low orbit, to get fuel again. That way, some tankers could be used in space until their rocket engines would wore out. But then, we could implement also unreturnable tankers: without wings and heat protection (which would made them again more mass effective). Those unreturnable tankers could be used to shorten expenses for some operation on orbit.

The docking device for such operations would be better done "universal" and standartized, all the same for all spaceships. Such a docking device could be seen on my drawings: every device have one hollow rod and one funnel (pipelines to fuel/oxydizer tanks should be able to recommutate by valves: so fuel and oxidizer wouldn't be mixed).

Also, it seems profitable to choose the one, standard fuel/oxidizer, that would be used for all possible space operations (this fuel/oxidizer would be also used to climb spaceplane to the orbit, because it is used by rocket engine of the third stage). This fuel/oxidizer should not be cryogenic, because it should not evaporate when spaceship is heated under the sunlight. When I invented this project (it was nearly 1999yr, or maybe 2000), first I thought about standard Soviet non-cryogenic fuel (unsymmetrical dimethylhydrazine + nitrogen tetroxide); but, it was clear even then, this standard fuel pair should be choosen very thorougly, and maybe some other variant appear in future. After that invention became known to others in summer 2005, nearly in winter 2009/2010, I obtained interesting hint from my team: for the standard oxidizer, we could use concentrated hydrogen peroxide. It is good for manned flight, because oxygen, water and energy could be obtained from it (and also, it is a good one-component fuel, e.g. for rocket backpack). Concerning the fuel for this oxidizer, there are a few variants (they were researched by Valentin Glushko): the best seem ordinary kerosene (Imp = 320sec), or pentaborane (Imp=380sec). Kerosene seems somewhat weak, pentaborane much better, but it is very toxic. So it rather depends on how good mass efficiency we could reach: if the Martian flight could be done with kerosene, than ok, but if not - than pentaborane seems to be better choise.

All those standard third stages: cargo, tanker, unreturnable tanker - are good for different operations in space (e.g. they could be used as orbital transfer vehicles for different satellites, provided the satellite has simple docking device, without refueling capability, just one funnel); but for landing on Moon and Mars, special landing modules should be additionally implemented.

The Lunar landing module could be very simple, transported on low Earth orbit in cargo bay, than refueled and transferred (of course, the standard docking device should be provided) to low Moon orbit. After several landing and take offs again on the Moon orbit (every time refueled) it could be abandoned there, or even returned back to Earth. Lunar module itself shouldn't posess a cabin for pilots:  most time, it'll transfer to/from the Moon some cargo, attached right on it's deсk. But if we want to land people on the Moon, a lightweight cabin could be mounted on the deсk, making the lunar module able to carry people.

The Martian landing module is the quite different thing. Mars have some atmosphere, and it's orbital velocity is higher. Therefore, we'll need much more fuel, to land even one man to Mars, and bring him back again to the low Martian orbit. And so, the Martian landing module could be done as a (very specific) third stage of my spaceplane; it takes off and climbs to LEO like the usual third stage; than, after a few refuelings, it is transferred to low Martian orbit, refueled again, and preparing to land on Mars (a man, or a crew of two, would enter into this apparatus from "ordinary" spaceship with living module, by docking on Martian orbit). During landing on Mars, the landing module got slower by reaction of Martian atmosphere (gliding on high velocity), and than lands on it's tail (as it could be seen on drawings). After the crew visited Mars, the module starts again to low Marian orbit (we'll need some thermal protection, and even some thermal shield on the bottom of the apparatus, to protect fuel from boiling during gliding through Mars atmosphere; and the mass efficiency should be really good, to made possible climbing to low Martian orbit again).

Landing on asteriods is an easier thing: the rocket backpack is enough, no other module is needed.

Also, it's worth mentioning, that wings and thermal protection of all those third stages (cargo, passenger, tanker, Mars landing module) could be profitably used for interplanetary trasportation. When the third stage (spaceship) arrives to planet with interplanetary velocity (e.g. backing to Earth from Moon, or arriving to Mars, etc.) it should made the velocity slower, in order to transfer into circular orbit. This could be done by flying through upper layers of the atmosphere of the planet on the high altitide, so the spaceship won't stay sunk in the atmosphere, but should exit from it back to space (with slower velocity). That way, transferring to the high elliptical orbit and passing through upper layers of atmosphere each time when at minimal altitude, spaceship could got much slower and transfer to low circular orbit - which would demand a lot of fuel without such an atmospherical trick.

This project was invented by me during 1997..2000 years; and in summer 2005, it became known to other people. At the moment, it is my intellectual property. Also, in order to prove my authorship and priority, I would pass a modern variant of lie detector (subliminal questions, answers from the unconscious, but without any possible control or accountability).