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Second Hypersonic X43 Scramjet Ready for Testing
Dan writes "I am sure most of you remember how NASA was forced destroy their first hypersonic X43 seconds in it's maiden flight, which was a big setback for the american hypersonic scramjet program. Well NASA just finished one of the final tests and is preparing to launch it as early as February 21! I wish them the best."
You miss my point. I think it is a great advance. I just wish such advances could be made without the need for a military factor.
"Who are in control, they are not in control of anything - they don't even control themselves!" - Glen Beck
A very large portion of the overall mass (and price) of current space transport is just the fuel to get out of the atmosphere. A scramjet could be used as part of a reusable ground -> high atmosphere lift system, where a separable high atmoshphere -> orbit/the moon/whatever system could detach and proceed from there.
AJWM (19027) sez: "For the several earlier posters who seem to think that this is the Holy Grail of Earth-to-orbit transportation -- well, maybe they're right in that it's about equally unattainable. Rockets work a hell of a lot better - as has been demonstrated by almost 47 years of orbital flight."
Rockets only work better if you consider the mechanical efficiency. If you throw cost into the deal, rockets fall apart. They're disposable for the most part.
A hypersonic air breathing first stage could carry a self-contained second stage to a speed and altitude that would make reaching orbit much easier, and do it far cheaper than can be done now.
The cheapest single disposable booster space shot so far was the Pegasus XL, for $13.5M. The estimate for the (cancelled) X-34 was $4M.
Interesting reading on the subject; Buzz Aldrin's patent for vertical launch flyback booster with orbital second stage: http://tinyurl.com/394qq
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
The X-15 pilots were needed mainly because they didn't have good enough automatic control systems. Now that we have them, there's no reason to risk human lives just to tinker with high-speed rocket planes.
The X-15 had such favorable PR that most people forget that one pilot lost his life when his X-15 spun out of control and disintegrated. IIRC, another barely escaped an explosion of the rocket engine during a ground test, and a third was lucky to survive the last high-speed speed mach-6 test that melted off a good chunk of the plane's tail fins.
If the failed first X-43 test had been manned, we may have had yet another fallen hero in the quest for knowledge. Luckily, all the incident cost was some time and money. It's nice to have celebrity astronauts and pilots to cheer on, but for these bleeding edge tests it's just not worth the risk if we can accomplish the goals without a pilot.
IMHO, the bigger letdown is that the space budget is so sapped from needlessly sending people into orbit to float on their butts in a tin can that most other development has slowed to a crawl. For example, hasn't it literally taken them years to put together this second test? Back at the height of the cold war, they would have tried a new flight within a few weeks or months. The same goes for developing a shuttle replacement. 10 years? It didn't take that long from before we had even launched a satellite to having the perfectly capable manned Gemini capsules in orbit. Ironically, NASA's need to devote huge resources to keeping faces on the news today continues to delay the date that space travel will be commonplace.
at that speed air becomes very different due to frictional heating. the aerodynamics are also somewhat different than supersonic flight which are much different than subsonic.
the main problems are heat though. the SR-71 flew around mach 3 and heat was its biggest enemy. also keeping the engines going at that speed was a challenge - few jet engines operate with those air speeds without self destructing.
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I work for the Air Force, everything I do goes into this mad, mad machine. It pays my bills, but in a way it is like a drug. I work with the best technology, but as much as I love the toys, I hate the end. I guess that makes me a whore. I accept it, but I don't like it.
"Who are in control, they are not in control of anything - they don't even control themselves!" - Glen Beck
... because scramjets don't work at subsonic speeds, you'd need something BEFORE the scramjets to get to mach, what, 7.
I'm sorry, i'm not seeing this as a solution to the cost of space travel at all.
I have a close friend of mine who flew with the Luftwaffe during WWII and had the privilege of flying a Me262. From what he tells me the 80% failure rate is highly exaggerated due largely to the fact that it seems to include things like the original test programs (wherein people tended to fly them into things like mountains).
Once pilots were properly trained the craft worked well provided you didn't try to cut power back too far. The only real issue with flying them was the danger of allied bombing raids and fighter strikes during landing and take off. By the time the Me262 was in any sort of regular use the allies held enough sway in the skies over Europe that a safe base of operations didn't exist for them.
Allied pilots learned quickly that against a Me262 they had virtually no chance in a dog fight, so they trailed them back to their landing fields (out of visual range) and hit them on the run way. Remarkably effective tactic for dealing with a far superior aircraft.
Killfile(TGK)
No trees were killed in the creation of this post. However, many electrons were inconvenienced.
I don't know how 'well' the DC-X did, considering that it burned itself up on one of its landings.
No, it did not. Here's the real story:
The DC-X project was initially run out of the Strategic Defense Initiative Office -- causing some turf envy at NASA. The vehicle went through a number of very successful flights (I got to see one of them) to ever higher altitudes and interesting flight profiles.
On one launch, some vented hydrogen had collected in the launch area near the base of the rocket and detonated when the engines lit. The shock blew off part of the fuselage but the DC-X just kept on climbing -- until the flight controller (I think it was Pete Conrad on that flight) and others noticed the debris falling from the vehicle and initiated the emergency abort/autoland sequence. The engines throttled back and the DC-X set itself down unharmed (aside from the initial damage). The fuselage was repaired and the DC-X flew again.
After SDIO's initial flight test sequence, the DC-X project was transferred to the control of NASA (remember that turf battle?). On the first NASA-controlled flight, a technician apparently left disconnected a hydraulic line to one of the landing legs (the rocket sat on a "milk-stool" support for launch). The flight went fine, the landing went okay until the engines shut off -- and then the unconnected leg folded up and the DC-X tipped over and fell. The impact cracked open the fuel tanks, the residual fuel caught fire, and the DC-X was destroyed.
No fault of the vehicle, just a technician fuck-up -- the equivalent of an airplane's gear collapsing on landing.
-- Alastair