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European Shuttle Program Update
Rolo Tomasi writes "ESA's reusable launch vehicle demonstrator, Phoenix, was recently wind tunnel
tested to determine its low speed aerodynamics. A free flight for Phoenix is
planned for early summer 2004. In case you haven't heard of it yet,
here's an article from last year, describing the Phoenix/HOPPER concept.
Here's another page at ESA, but it seems to be available only in German. What's interesting is the first sentence of the DLR press release, stating that (my translation) 'Europe's future and
competitiveness in space substantially depend on an autonomous access to space and 'on a drastic decrease in the transport
costs of getting there.'"
Actually, one design I saw was for a winged main booster. The idea behind it was when it detaches from the shuttle it could glide back down to earth.
But yes, the Space Shuttle wasn't exactly what the space program needed for the long term, it was just the cheap sucker that passed congress. Don't get me wrong, it served it's purpose.
But as far as going back to a capsule, well you could but I think part of our experimentation is attempting to actually create a vehicel that at some point could do a moonshot, land, launch, return, and refuel and get back underway in a short time. And yes, we do need a fleet of more traditional rockets, not so much because they are cheeper to build, but that whole issue of getting into higher orbits that the present shuttle just can't do.
Landing has one key advantage vs splashdown in the fact that even with the flying brick shuttle you have some control as to where you land and how you land. If you screw up a splashdown and hit.. for example... land, you are pretty much screwed.
Heat tiles are the cutting edge of technology... for 30 years ago. Modern metal alloys exist that are structurally strong, yet can also withstand the temperatures of re-entry directly without having ceramic tiles. My guess about the different approaches:
* Ceramic tiles = obsolete.
* Heat shield = more weight to carry up with you = inefficient for payload and fuel.
* Parachutes = explosives / mechanisms to release the chute are needed.
Wings & landing gear may be the safest option given that if the landing gear fails - you can still slide along the dirt and live. If you remember capsules sinking and astronauts nearly drowning on a regular basis with splashdowns, an airport landing is looking more and more desirable.
An alternative is to design for steeper/shorter reentry and to use multiple orbits to ensure correct positioning so that the landing could take place somewhere reasonable. This is what NASA wanted but it was nixxed by the USAF as they needed to be able to fly all the way down.
The ESA could select something more like the original NASA flight profile and thus make something reusable, for less money. Purely ballistic reentry vehicles are fine, but they don't scale up so easily.
See my journal, I write things there
Anti grave is not the answer either. The applied use of directed magnetic fields is interesting again though. The research into this stopped in the 1960s when the distance calculations to reach escape velocity on a field launch ramp was calculated at roughly 30 miles of ramp. The problem was that air density at the ramp hight of 13,000 feet was still too dense to take the velocity achieved without supper heating the payload! Seems to me in the Andes there are places the ramp hieghts could reach 20,000+ feet adjacent to the Altiplano but the ramp construction contraints were considered too great. Well we have much better mag lev and supperconductor tech now and we also have much better high altitude construction techniques. The only reason this tech is not been brought forward is the tech would need to be applied somewhere other than in the US! It would require real international co-operation and would in the long run be so much cheaper than rockets. Houston and the Johnson would go out of business. Fuel payloads could be launched also and staged late burning correcting vessels could also be devised. Get your mind away from rockets for just one second. Yes they are important for getting around once you gain escape velocity but they are a stupid and dangerous way to achieve it!
OH THE SHAME I fell off the wagon and use sigs again!
Reusable spacecraft are actually much cheaper to use, just not the way the Shuttle does it. The Hopper doesn't have any of that tile nonsense. From the third link (my translation): "Upon reentry of the compact Hopper, the reentry angle into the atmosphere is optimized in such a way that the resulting heat from friction is significantly lower than on the US Shuttle. Thus the delicate and expensive tiles can be replaced with a cheap and maintenance friendly heat protection system."
Did you know you can fertilize your lawn with used motor oil?
Actually, capsules are much safer than "space planes". Russians recently suffered a generalized computer failure on reentry and landed without any problem, far away from the expected landing spot. Oh, and you don't need to "splashdown" in water, it can be done on the ground too. Also, you don't need all that dead weight : wings and all the control and surfaces needed for the reentry. That's several additional tons you need to throw on orbit, tons you cannot put in the payload. So, if you take the shuttle motors and reservoir (you don't even need those expensive refillable boosters any more, but you can take them too), then replace the shuttle body by a (reusable) capsule, you have a much much cheaper (and efficient) reusable vehicle. And it is also safer. And it is able to lift an heavier payload on a higher orbit. And ... why the hell did they add those wings already ?
I guess it is an image problem. They want a "spaceship" ...
Kirinyaga
What metal could withstand 1,650 C? I am seriously curious here because nothing that I know of can even come close to withstanding that much heat for that long of time.
I remember reading a book about turojet (fan?) engines and how the blades, even made using fancy techniques such as single mold crystal or something like that, cannot withstand the heat inside a modern military jet engine and must use a series of complicated air ducts to vent fresh air over the metal. If they can't make a material to withstand the heat of an aircraft engine why would they be able to make a material to wisthand 10's of minutes of 1000+ C heat?
Your first point is absolutely valid to a certain extend.
/. is linking towards non-English sites, there is someone posting a translation in here. (t+5minutes: automatic ones like babelfish, altavista or google; t+20 minutes exerpts in a usable translation; t+1h a nice translation).
While I am a German native speaker, the majority of the information I read is
a) English
b) German with at least 20 per cent English buzzwords.
Every time
This is actually a good thing and the people who are doing these translations are heavyly dependant on your feedback.
From a pracical side, it would be not so nice not to point to non-English sites, when they are covering an interesting topic. As long as there are people here who are helping those people who have chosen to learn different languages, I don't see you being handicapped.
Btw. do I hear you volunteering to answer stupid questions from non-English-native-speakers to explain rare english words which can't be found in an online dictionary for some reason?
Its an old point, but worth repeating:-
I dont believe NASA/ESA will ever deliver
really cheap space transport - they are
good at some things, but they are just
not the right people to do it..
The X-Prize has yielded a whole raft of
promising new vehicles, all for a measley
$10 million. (remember the the shuttle is
$600 million per launch)
Just set up "competitions" for certain
objectives and let entreprenuers figure
out the rest..
"You lied to me! There is a Swansea!"
In summary, it's you, my American friend, who might really need black humour soon. After all, it's highly unlikely that the situation in Russia will become worse.
Future Wiki -- If you don't think about the future, you cannot have one.
The refractory metals are better, but less commonly used. Columbium/niobium is reasonable to form. Molybdenum and alloys like TZM take a bit more heat, but have a potentially annoing ductile to brittle transition point for systems that will cold soak. The state of the art is irridium coated rhenium, which doesn't melt until 2466 C / 4471 F.
We fabricated a TZM chamber a while ago at fairly high expense, but still burned through it after an extended length run:
burned TZM
This experience has convinced me that active cooling methods, like transpiration cooling, are probably a good idea for high reusability reentry vehicles.
John Carmack