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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 are so right just like all the other stuff for the millitary like, jets, helicopters, antibiotics, and high speed computers this will do nothing for us.
As far as freedom and peace. There are different opinons on that one. While Bush might have acted without just cause in Iraq. I bet that a few Thousand people in Iraq feel a little more free and a little safer with Sadam in prison.
Say what you like he was a sick and twisted mass murder.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
...as a scramjet takes in the oxygen it needs for combustion (whereas solid rocket boosters hold the oxygen as part of their solid fuel). Would they use the scramjet to get to such a high speed (at altitudes where there is still oxygen available) that you break free from the earths gravitational pull?
I am NaN
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
Actually, you can do a simple 2 stage with scram taking us into near leo and then the upper carrying us out via simple hydrogen rockets.
I prefer the "u" in honour as it seems to be missing these days.
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.
granted, but considering that the american military can easily put a sixeable ground force anywhere in the world within 24 hours, not to mention bomb anything off the map within only a couple of hours, I really don't see how they would use this as some kind of bombing vehicle (seeing as it would move way too high and way too fast.) perhaps it would make a decent vehicle for spy photography or for interception of ballistic missiles (even then folks are gonna have to be awfully quick on the draw) its speed mostly rules out the use of it as a conventional bomber. the 2 uses that I pointed out, the spy plane and the missile intercept vehicle, will both have the effect of lessening the amount of death associated with war. a new spyplane allows for better intelligence, which leads to more surgical strikes. the united states wouldn't dare to have a scorched earth war policy nowadays, it just wouldn't fly. the ballistic missile intercept vehicle's life saving abilities are two-fold: stop the actual missiles, and show of force that indicates the futility of attacking with more ICBMs.
so when you look at those points, and what the civilian applications could entail, it doesn't strike me as a primarily military technology. I actually think there is not much that IS limited only to the military anymore (i.e. GPS, hummers, you name it.)
I understand the concern, and it's a perfectly valid fear, but I don't think these planes will make the american military any more of a nightmare creature than it already is (to some). the american economy, OTOH...but that's a different rant (possibly entitled "globilization? try solar-systemization!")
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.
That would be after the program was turned over to NASA. It took them only one test to destroy any competition to their cash cow shuttle program by leaving a hydraulic line for the landing gear disconnected.
"HyShot was fitted inside the nose cone of a two-stage rocket, which boosted it to an altitude of 300 kilometres. The rocket then plummeted back to Earth, reaching a speed of Mach 7.6.
Data data from the flight, which has now been fully analysed, shows the engine fired successfully before it and the rocket smashed into the ground, about 400 kilometres west of Woomera in South Australia."
Great, a supersonic lawn dart. Not to belittle their efforts, but it's different smashing shit into the earth using a scramjet than it is to actually power an aerospace vehicle with one.
Do the math.
Fuel is cheap. With a rocket, all the energy you put into lifting and accelerating that fuel you gain back when you burn it.
Burning air (as a scramjet) means (a) you're handling 400% more mass than you need to (the nitrogen) and (b) unless you add energy to it to accelerate it, you don't get as much momentum kick when you burn it.
You'll note that they accelerate the damn test article with a rocket.
-- Alastair
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 perfect statement of one of the most persistent and erroneous misconceptions in astronautics. Price it out: rockets typically burn on the order of 200kg fuel to put a kg payload into orbit (double this for manned, halve it for simplest payloads). LOX is around $0.16 (USD)/kg and kerosene around $0.40 (USD)/kg. Burning 2.5:1, you pay $0.22/kg fuel, or $45 per kg into orbit. Now add tankage, engines/motors (hella pricey, used once and tossed or essentially rebuilt), systems integration, logistics, infrastructure, admin overhead, and you get ~$9,000/kg delivered. Fuel is only 0.5% of the total cost. It is left as an exercise to the reader to figure out why our space program is so inefficient.
To recap this week's lesson for rocket scientists and voters: know some numbers before throwing your weight behind multibillion USD expenditures.
Sources: astronautix.com; Wertz, Space Mission Analysis and Design, 2nd ed., Microcosm: 1992, p. 731.
I understand that supersonic combustion is a neat trick, basically the flamefront has to keep up with the aircraft as it moves through the air. Since normally a flamefront is limited in its speed by the speed with which the molecules can contact each other and thus react chemically, getting that flamefront to keep up with the aircraft involves getting the local pressure high enough that molecules can bump together at "supersonic" speed (I doubt it is actually supersonic in the region and under the temperature/pressure conditions of the combustion).
But how does one exert pressure against something that is not there? Imagine the classic balloon we blow up and then release. The pressure differential between the front of the ballon and the area where the air is escaping causes the balloon to move. Pop the balloon with a pin and it goes nowhere, because the pressure is released everywhere at once. A ramjet compresses purely from the ramming of air into the combustion pipe. Without a compressor against which to enclose the combusting mixture, how is thrust generated?
Something I'm missing. We know it works, we've seen it. It just doesn't make sense yet.
To hear the gods laugh tell them your plans.
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
Sure, there is a modest up-front cost, but once it's built, transportation to geo, HEO, and beyond will be relatively inexpensive.
It may sound unfeasible at the present time, but the US congress is funding research on it.
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
I think these names are cool, but these names for the electronic warriors are very different from the more macho names for the gun and bomb warriors.
The biggest problem with SCRAM jet tech is that the faster the plane moves, the longer the combustion chamber has to be to get the benefits of combustion, since you can only slow down the inflow so much. I don't exactly recall the numbers of the top of my head, but 18 ft seems to ring a bell for combustion chamber length at somewhere around Mach 5 (could have been faster, don't recall). That is not inclusive intake and exhaust nozzles. This presents issues as the combustion chamber length has to be dynamic with speed.
The cesspool just got a check and balance.
Nope. That's the stochiometric ratio, nothing like that is ever used. Actually it's more like:
4 H2 + O2 -> 2H20 + 2 H2
(Actually, it's much messier than that, you really get a bunch of HO's O's H's H2O2's but that's the gist of it).
The point is rockets run very fuel rich, because that gives a much higher exhaust velocity (the hydrogen has less places to hide energy than complex molecules- you want as much energy as possible to be in kinetic form), the scramjet would do the same thing. So your fuel/oxidiser ratio is way off.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"This story is documented in a new, VERY EXCELLENT book, "Lost in Space: The Fall of NASA", by Greg Klerkx, page 107. The description above is echoed in the book. The 'turf war' is NASA vs. all projects that threaten the shuttle/station. There are wonderful people working at NASA, but there are also career bureaucrats who delight in protecting their program and making politics out of everything, forget the engineering.
This book is fantastic - it highlights exactly why each one of the advanced projects - NASP, DC-X, K-1, X-38, etc., failed. They were killed, most often by gobbling up the entity, doing a 'study' and condcluding the idea was, in the end, unworkable (regardless of initial promise).
The power bases at NASA are multiple levels deep, cross-organizational, and so entrenched the best thing would be to eliminate NASA, fire everyone, and farm out the projects to Darpa, JPL, DOD, and several other departments. Then, a few years later, re-form the organization under a different name, like the Dept. of Transportation's Federal Bureau of Aerospace Exploration.
This new dept. would contract to purchase exploration missions on a COD basis (my term) - cash of delivery. We want to buy images of Mars at 1 pixel = 1 meter, we'll pay $1 per pixel for them. You get there, you do the job. If you succeed, we'll buy the pictures. You take the risk, you optimize your own business plan and technology.
Likewise, we'd pay to put FBAE astronauts on Mars - We get to choose the mission profile. That means we specify the location and the scientist, you put them there. We pay x days minimum for their time, at $20K dollars per hour.
We should pay for all material delivered to orbit on a per-pound basis, auctioned off. We have a package - a probe, let's say - we want in geosync. You pay for the insurance on the probe. We only pay if it is delivered to the location, working.
Further, all science has to become public knowledge. Engineering specs for all components must become public record before payoff is made. This encourages patenting improvments, and makes everyone more efficient.
Just some ideas I've come up with after reading this book (some ideas stolen from the book, some are my own).
Lost in Space: The Fall of NASA, by Greg Kerkx at amazon here
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