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#26 Re: Interplanetary transportation » Three - staged, completely reusable spaceplane, reaching Moon & Mars. » 2017-05-23 13:50:12
To this I would add the comment that no combined-cycle engine concept is an off the shelf item ready-to-apply, any more than scramjet is. Both have been “15 or 20 years away” since the 1960’s, same as controlled fusion. You cannot go to a manufacturer anywhere and buy one. They don’t work yet, except as very limited, extremely-experimental devices.
If under "combined-cycle" you mean something like SABRE engines of Skylon, then it's agreed. These combined devices seems impossible in real world; too much adverticement with no results.
That being the case, I see no practical applications for spaceplane concepts except as multi-stage devices to low Earth orbit, and then only for delivery of people at low payload fraction, not bulk cargo.
Surely, spaceplanes are not intended to bring lots of tons of cargo on orbit; instead, they could fly to orbit very frequently, with minimal price per kilogram.
But also, you forget my invention of multiple and multistage refueling; this made it possible for reusable spaceplanes to reach Moon, Mars, asteriods, and so on.
To bring a lot of cargo on orbit, surely it's better to use reusable rockets (not as much re-launches as for spaceplanes, but much more cargo per one launch). If someone would be interested, I have a project (it's my intellectual property, either) of such a completely reusable rocket (taking as a prototype rocket Energiya):
http://lychakivsky.dreamwidth.org/7959.html
And I don’t think anybody will ever do that job with a turbojet-powered first stage. The frontal thrust density is just too impossibly low for anything like that to ever be practical! You’re much better off with rockets that can produce gobs of thrust from a small package at takeoff, just when you need it most, because your takeoff weight is so heavy.
Let me remember you Ukrainian "Mriya" aircraft. It is not only the most powerful cargo aircraft in the world - it also is intended to be exactly the said turbojet first stage for space launch. Maybe, you heard about MAKS project (small shuttle with external fuel tank) or "Air launch" (two-staged rocket system; as far as I'm informed they even evolutionize it to complete reusability), both intended to start from the top of "Mriya".
The statement that "supersonic ramjets" are 1 < M < 6 is NOT actually correct in real practice. There are low speed designs that cover 0.7 < M < 2-ish, and high-speed designs that cover 1.8/2.5 < M < 4-to-6 (limited at both ends more by airframe drag relative to available thrust). They differ by some very specific geometric features that you just cannot convert back-and-forth.
In my project, ramjets should start at M2.5 h=25km, and climb upward to M5(6) h=50 km. So they could be specialized for that altitudes and velocities (by "some very specific geometric features", as you have said).
I don't think you'll like the engine inert weights or the required frontal cross-sections for a turbojet first stage, either. The numbers entirely rule out vertical takeoff, and it looks rather ridiculous for horizontal takeoff, if your payload is bigger than a small dog.
Why? If we take, just for estimate, turbojet engines of Soviet Tu - 144: it's four engines enable take-off weight of more than 200 000 kg (with the aerodynamic characteristics, very similar to my spaceplane); so, if we'd implement my concept of spaceplane with those engines, we would end up with final cargo on LEO estimately 2 000 - 3 000 kg (which is already not bad). And those engines were implemented in 1960s; now, after half a century pass, I think it would be possible to implement more powerful engines, so take-off weight could be nearly 500 000 kg, and final cargo on LEO - estimately 5 000 kg. That would made achiveable all the claimed functionality: including manned trip to Moon, Mars, and asteroids.
#27 Re: Interplanetary transportation » Three - staged, completely reusable spaceplane, reaching Moon & Mars. » 2017-05-23 12:32:23
I'm writing somewhat large answer on all the questions; it should take some time, but just a small remark meanwhile.
Space Shuttle never had a real military purpose.
Oh really? Have you ever heard about SDI? It's orbit-located components (many hundred of tons) were supposed to be brought to orbit by Space Shuttles. In fact, it was the success of Shuttle, what made SDI a real threat for USSR.
If your design does, then see if you can convince the Russian government to develop your design.
Russian? You said that? Don't forget, that my country Ukraine is waging heavy non-declared war against nuclear Russia, at the time when the West is afraid even to sell us infantry anti-tank missiles, let alone to uphold the obligations due to Budapest Memorandum (it was nuclear disarmament of Ukraine under safety guarantees from the US and UK, let me remember it).
Don't call me a traitor.
#28 Re: Interplanetary transportation » Three - staged, completely reusable spaceplane, reaching Moon & Mars. » 2017-05-23 03:33:06
Is there any technical basis for the claim that the Star Raker would not be able to reach orbit, or is that just an opinion?
This is easy to estimate. On turbojet engines, the Star Raker will reach approximately v=1km/sec, h=30km. All the rest of the speed and altitude needed to climb on the orbit must be reached on a rocket engine, while still carrying heavy take-off chassis, spent turbojet engines, as well as wings and fuel tanks completely covered by heat protection. For conventional (non-nuclear) rocket engines, this is impossible with the mass efficiency provided by modern materials.
Are there any operational scramjet engines larger than the ones on small missiles?
Among large flying vehicles - in the 1950s, Soviet big intercontinental cruise missile "Burya" had flown. Please read:
http://www.airbase.ru/sb/russia/lavochkin/la/350/
If not, then this concept is no more feasible than Star Raker. I've never seen or heard of any operational scramjet-powered vehicles, although NASA and DoD have certainly tried on several occasions. Personally, I think both concepts are grossly unrealistic on a cost-per-flight basis. The US had an operational lift body program for decades, but nobody I know of would ever argue that it was in any way cost-effective.
Supersonic ramjets (1M < v < 6M) are well-calculated scientifically and could be scaled for large aircraft. Primarily, they were not put on large aircraft simply because they can not work on zero velocity, without an accelerating block. But the first stage that I invented, which you see on the drawings, is just such an accelerating block. From the point of view of costs efficiency per one flight, supersonic ramjets are much better than rocket engines, because they have a much larger working life.
The Soviets had one flight with Buran, but that vehicle was every bit as unrealistic to operate, on a cost-per-flight basis, as the Space Shuttle was.
It is a big mistake to reduce all the world to commercial efficiency. Both Shuttle and Buran were created more from considerations of national prestige and global military confrontation. Without success of Apollo and Shuttle, the US would stay below the USSR in space race, which would have decisive consequences for the development of the whole global political situation: without these projects, we would live in a completely different world now.
Few, if any, fully reusable vehicles confer operating cost advantages over current reusable booster technology rockets like Falcon 9 and Falcon Heavy. I doubt this concept is any different in that regard.
It rather depends on what kind of commercial payload you are counting on. If we are talking about a few launches per year, then maybe SpaceX reusable boosters could be enough.
However, for example, novadays we face the task of creating a global space Internet, based on many thousands of satellites. For this project (which, by the way, is commercially very profitable), reusable rocket boosters have too small working life, they require too expensive maintenance before each launch and they are not completely reusable when flying to high orbits. Such a large number of satellites could be placed on orbits and maintained much cheaply and conveniently by the spaceplane, which would provide a significantly lower price per kilogram on orbit, and could be re-launched much more times, without need in additional pre-launch service (this is exactly a reason why reusable spaceplane is better than reusable rocket booster).
In addition to commercial payload, this spaceplane could also become a key for a wide variety of military applications ("star wars").
Thus, it is profitable to create such a spaceplane, the costs of its creation should be justified: both from a commercial and from a military point of view. And if this spaceplane would be created, it could be used also for prestigious achievements in space explorations. Only a Martian landing module should be added - and the same, commercially profitable spaceplane, could be used to fly to Mars. For flights to the Moon, a lunar landing module is additionally needed; for landing on asteroids - a rocket backpack (and it also could be commercially profitable: e.g. space tourism).
#29 Re: Interplanetary transportation » Three - staged, completely reusable spaceplane, reaching Moon & Mars. » 2017-05-22 01:41:32
This is akin to the fully reusable Rockwell Star Raker concept, but substantially more complicated.
Not quite so. Rockwell Star Raker, and all similar HTHL SSTO concepts (X-30, Skylon, etc.) are plainly not realistic. To put it simply, they would not be able to reach orbital velocity. It is by far not possible to reach these 7.9km/sec in space using only one reusable stage (with non-nuclear engines, to be specific).
Moreover, even when you use two reusable stages (e.g. in Saenger-2 concept), reaching of orbital velocity seems also nearly impossible. Maybe, it could be possible in future, with more sophisticated turboramjet engines - but not at the present level of technology; and even if the two-staged concept would in future become able to reach orbit, anyway its mass effectiveness would be much, much worse as compared to three-staged design. But again, if you already use two stages, so your spaceplane is not all-in-one thing anyway, so why not use three stages? Especially, taking into account, that three staged concept perfectly fits for three different types of engines: turbojet, ramjet, rocket.
This design provides the possibility to reach orbit on the present level of technology; and with using of multiple and multistaged refuelings - it also makes possible reaching of all Earth orbits, Moon, Mars, asteroids on the same universal spaceship. I have not seen any other realistic concept of spaceplane, that would be even nearly so powerful and universal.
#30 Interplanetary transportation » Three - staged, completely reusable spaceplane, reaching Moon & Mars. » 2017-05-21 13:20:07
- Yuri Pilipishin
- Replies: 46
Three - staged, completely reusable spaceplane, with horizontal take off and landing; the first stage uses turbojet engine, the second stage uses ramjet (scramjet) engine, the third stage with rocket engine (the second stage is also used as an external fuel tank for the rocket engine of the third stage). A special feature is the possibility of multiple refuelings of the spaceship (the third stage) by (reusable) tankers, made in the same tanks which are used for climbing into orbit; such refuelings coulds be also multi - staged, due to which the spaceship could reach even a geostationary orbit, Moon, Mars and asteroids (the only price is the amount of launches of reusable tankers, and the time needed).
For landing on the Moon and Mars, special reusable modules are used.
In order to significally reduce amount of launches, needed for Mars mission, cheap standard non - reusable tankers could also be engaged (they are used for transporting fuel in space, and could be abandoned in space, presumably on Mars orbit, after mission is finished)
That way, this is the only available realistic project (as far as I know) making it possible for humans to reach Moon, Mars, asteroids, and return back to Earth, using non - nuclear reusable spaceship.
The general design could be understood from drawings:
A more detailed description of the project is in Ukrainian, those who are interested could translate it by Google (please note, this is all my intellectual property):
http://lychakivsky.dreamwidth.org/7865.html
http://lychakivsky.dreamwidth.org/8214.html
http://lychakivsky.dreamwidth.org/13658.html