Second Hypersonic X43 Scramjet Ready for Testing 434
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."
Comment removed (Score:5, Funny)
Ah, but this one's different... (Score:5, Funny)
This one, IIRC, is built for use by Halliburton to deliver water to Iraq.
It's all no-bid, hush-hush, very patriotic and stuff.
Re: vegan reduce IQ? That's unpossible! (Score:3, Funny)
I am an vegan and my Ike you is
Wat was the queschin?
Scramjet and space flight (Score:5, Insightful)
Happy Trails,
Erick
I don't get how that should be possible... (Score:3, Interesting)
Re:I don't get how that should be possible... (Score:5, Informative)
The thing about getting to orbit isn't so much the vertical velocity required, its your horizontal velocity. Rockets going to orbit don't go straight up; if they did they would end up coming straight back down... The trick is getting enough horizontal velocity so that as gravity pulls you down towards the earth you are moving fowards fast enough that you are continually "falling over the edge" of the horizon.
With a scramjet you only need half the fuel of a traditional rocket, as you burn oxygen from the atmosphere instead of carrying it all with you. Yes, a traditional rocket IS needed to get you out of the atmosphere, but using a scramjet for the initial acceleration would end up saving a lot of fuel, and hence weight.
Less than half (Score:5, Insightful)
2 H2 + O2 -> 2 H2O
Which means that by mass modern rockets use about 8 times as much oxygen as they use hydrogen.
Caveat (Score:5, Informative)
However, the X-43A vehicle does indeed use hydrogen for its fuel. (Perhaps for that very reason?)
Re:Caveat (Score:4, Informative)
Wrong! Re:Less than half (Score:4, Interesting)
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.
The lure of the airbreather (Score:5, Informative)
So, why carry the oxygen, why not get oxygen from the air? For LH2-LO2, that eliminates most of the mass and solves the mass fraction problem right away. The 1960's Aerospaceplane project originally considered liquifying the O2 from the air -- careful tweaking can be enriched on LO2 over LN2 on account of boiling point differences. You used (boiled off) some of your LH2 to get the coolant.
The trouble with LACE (liquid air cycle engine) is that you have to slow down the air rushing into the inlet (or speed it up to your rushing vehicle). If you are going fast enough relative to orbital velocity, slowing the O2 down in the inlet will heat it so much that you cannot burn it with H2 and get any energy -- the stagnation temperature of the shock front gets higher than your flame temperature. Hey, if this were not the case, orbital velocity would be low compared to rocket exhaust velocity and mass fraction would not be a problem.
Ah, the scramjet, and scramjet was also considered for Aerospaceplane. It is literally the taking a drink from a fire hose. You only slow down the inlet air stream a little bit so you get some compression, and burn H2 in that hypersonic air blast and 1) hope that the flame doesn't blow out and 2) hope that you get any positive net thrust out of the works.
If you could get any single-stage-to-orbit vehicle built that had reasonable engineering margins, you could fly it like an airplane, and even if it had a very small payload, you could fly it often enough to make a profit. NASA blew a wad in the late 80's, early 90's with National Aero Space Plane (NASP) and pulled the plug. But forget the scramjet -- if you could build a rocket out of composite materials, you could get the mass fraction. NASA blew a wad in the late 90's on the X-33 and then pulled the plug.
Jerry Pournelle states that the Strategic Defense Office (which needed a way to loft Star Wars into orbit) could have done the job -- the DC-X demonstrated the control of vertical-takeoff vertical-landing (lands tail first on rocket flames just like in Buck Rogers -- maybe not so wasteful of fuel because reentry is mainly aerobraking and landing is to last applying the brakes on a mainly empty vehicle), and he talks about a program called Have Region (don't know the source of Air Force code names, although NASA these days seems to have projects code named Have Boner) that proved that the mass fraction target was achievable and one didn't need scramjets.
Re:The lure of the airbreather (Score:3, Interesting)
Re:The lure of the airbreather (Score:5, Interesting)
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.
Re:The lure of the airbreather (Score:3, Interesting)
This book is fantastic - it highlights exactly why each one of the advanced projects -
Air Force code names (Score:3, Interesting)
I think these names are cool, but
Uh this would still be a 3 stage launch though (Score:4, Interesting)
I'm sorry, i'm not seeing this as a solution to the cost of space travel at all.
Re:Uh this would still be a 3 stage launch though (Score:5, Informative)
Use turbojet stage for takeoff.
Bring in Ramjet stage at transsonic speeds, transitioning to full ramjet about Mach 1.5 to Mach 2.
Bring in Scramjet stage from Mach 3-4, transitioning to full scramjet at Mach 5-7.
Bring in Rocket stage at mach 10-12, transitioning to full rocket at Mach 14-16.
You see, that it's rare that any single stage is purely one thing or the other. Scramjets are not the solution to space travel. They're one piece of the puzzle. Reducing the cost of flight to space by 5% is something which would still be worthwhile, and airbreathing flight certainly has great promise to do far more than that.
The problem is that at the moment it's only that: promise. These tests are to see if we can turn promise into reality.
Re:Uh this would still be a 3 stage launch though (Score:4, Informative)
Obviously there are a lot of people studying whether the trade off comes off positive or negative for the cost to orbit.
Re:Uh this would still be a 3 stage launch though (Score:3, Interesting)
You're thinking re-usable SSTO. Nothing says scramjets are only for SSTO or reusable. Think of replacing the second stage on your favourite rocket with a scramjet, and you'll see one possibel option.
Re:Uh this would still be a 3 stage launch though (Score:3, Insightful)
It's used to dangle the expensive Pegasus conventional rocket that the X-43 uses for its first stage.
Re:Uh this would still be a 3 stage launch though (Score:3, Informative)
Re:I don't get how that should be possible... (Score:3, Interesting)
Re:I don't get how that should be possible... (Score:5, Informative)
That's not entirely correct. The O2 is a third of the mass. Keep in mind that in addition to eliminating the weight of the 02, scramjets push such an amazing amount of air out the back that they are far more efficient than rocket engines.
The main problem with space launches is the initial climb and acceleration, when you are pushing forward all of the craft's stages and fuel. By eliminating the 02, it translates into vastly, vastly smaller requirements.
Better to simply make the fuel and oxidizer tanks bigger (because fuel and oxidizer is -so- much a -tiny- part of a launch cost) and stick bigger engines on it.
Scramjets are far simpler than rocket engines. It would be much cheaper to build boosters that use a scramjet as a first stage as opposed to a rocket engine. The fuel savings, the increased payload, and the cheaper cost all make the scramjet a superior option.
Re:I don't get how that should be possible... (Score:5, Informative)
I'm not sure what relavence the % of Oxygen's mass is. The main point is that the mass doesn't matter if it is fuel/oxidizer mass. Typically you want -more- of it because it makes life so simple if you can have more powerful engines that consume it in large quantities.
--You are both wrong. In a Liquid Hydrogen/Liquid Oxygen rocket, 8 times as much oxygen mass is needed compared to hydrogen mass.
4H + O2 => 2H2O
Oxygen is 16 times more massive.
Rocket engines are -very- efficient, but of course they have to push their own oxidizer along.
--I dont know how you define efficiency but in my aproximation having to lift 20x the payload mass because of extra fuel is an inefficency.
Vastly smaller requirements for what? O2 which is amazingly cheap? Why bother?
--Going back to the previous point. Its not a matter of the price of oxygen, but the bulk that it causes to carry it. This results in hugely more complex lift vehical, which is... um... huge, and expensive.
You don't get very far up before you run out of oxygen to power a scramjet
--In fact it cant operate at low altituteds because there is too much oxygen.
scramjet... weighs quite a bit itself.
--Compared to fuel weight ???? Are you nutts ?
Sir, I dont think you understand this at all.
Re:I don't get how that should be possible... (Score:4, Informative)
Ahem. That's what's called the stochiometric ratio, which is NOT used for rockets. Rockets burn very fuel rich; because (to oversimplify somewhat) the light, hot, hydrogen gives better thrust than the water (less places to hide the energy in simple molecules like hydrogen- rockets want the energy to go into kinetic energy of the molecules rather than internal vibration modes of the molecules).
The upshot is that rockets typically run with about 2/3 by mass of the propellent oxygen, with the rest made up of the fuel.
IRC This translates in the case of Apollo as 6 moles of hydrogen per mole of oxygen- but 8 gives a higher exhaust velocity, but hydrogen tanks are too heavy so the *vehicle* optimises at a lower ratio.
I dont know how you define efficiency but in my aproximation having to lift 20x the payload mass because of extra fuel is an inefficency.
It's so not as simple as that though- scramjets suffer from incredible heating effects from going mach 8 in the atmosphere, they suffer enormous drag effects, they end up using more *fuel* (as opposed to propellent), and the scramjet engine is bigger and heavier than a rocket engine for the same payload- furthermore engines cost money, whereas LOX and LOX tanks don't. (Fuel is pretty cheap too in fact).
This results in hugely more complex lift vehical, which is... um... huge, and expensive.
No. Perversely perhaps, it's bigger, but cheaper; because 60% of the mass is LOX, and the rocket engines are smaller and cheaper.
Re:I don't get how that should be possible... (Score:3, Informative)
Oxygen has an atomic number of eight - and an atomic weight of 15.9994 [webelements.com] - against Hydrogen, atomic weight 1.00794.
-Chris
Re:I don't get how that should be possible... (Score:2, Informative)
the rocket can be small in this case since the scram jet is going fast enough that it could get enough oxygen from the atmosphere at very high altitudes to burn.
I'm Glad (Score:5, Funny)
...though I bet Bush will fund it so he can land one on an aircraft carrier!! *rimshot*
Re:I'm Glad (Score:2)
I saw a thing on the history channel about the development of the jet engine. It took 20 years before jet engine technology was really usable. (The nazis developed the first jet engine.. and it wasn't until the 60s when jet engines started being really used)
So I'd say the scramjet has room for a few failures.
Re:I'm Glad (Score:3, Informative)
I'm not sure whether you're high, or the History channel. The Messerschmitt 262 [channel4.com] was the first warbird with jet engines, and had it entered the fray just a few months earlier, it might have changed the course of history. The jet engine was eminently useful in that application at that time.
Re:I'm Glad (Score:3, Informative)
Re:I'm Glad (Score:5, Interesting)
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.
Re:I'm Glad (Score:4, Informative)
Both military and civilian jet aircraft were doing well in the 1950s.
And as for the Nazis developing the first jet engine, Sir Frank Whittle might have an argument with that. (Although the Germans may have had a jet -powered aircraft in the air first.)
Whittle patented his design quite early... (Score:3, Informative)
IIRC, according to "Inventions that changed the world", Whittle patented his jet engine quite early on (I think before he'd built a working version) which meant that it became public knowledge.
It's quite possible that the Nazis saw this patent and, of course, probably didn't feel the need to pay any licencing fees for their d
Re:I'm Glad (Score:3, Interesting)
Re: HEO and beyond (Score:3, Interesting)
The space [www.isr.us] elevator [spaceelevator.com] will.
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 [liftwatch.org] on it.
Excellent (Score:5, Insightful)
Re:Excellent (Score:3, Interesting)
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.
Re:Excellent (Score:5, Interesting)
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.
Re:Excellent (Score:2)
All the money would be diverted to social programs if there weren't military threats driving the advancement of technology.
Re:Excellent (Score:5, Insightful)
Re:Excellent (Score:2, Informative)
Look at all of the effort people have used to build pyramids and cathedrals - really wonders of their ages - and all in the name of religion.
Same with the military - People just don't put forth the effort required to make breakthroughs like this without some greater need (national protection or God).
Re:Excellent (Score:2)
Re:Excellent (Score:5, Informative)
Humans will not be free until they have stopped being afraid of death and the scare tactics used to control the weak religious minded, such as belief in heaven, hell, judgement day, etc. nothing good will happen. All are used as tools by the Leaders and Pontiffs to keep the masses in line.
Until the substitution of reason and thought for blind faith happens nothing will ever change.
But honor the 2 biggest killers of mankind - the military class and religion as advancers of society? Fuck, no. They are the biggest millstones around the human condition.
Re:Excellent (Score:5, Insightful)
I'll give you that Religion has been bastardized by many people to serve their own purposes, but:
1)It doesn't make 'religion in general' a bad thing. Having a few, or even a majority of people that claim to adhere to a creed screwing up doesn't automagically make the creed stupid.(not believing in religion is, of course something that's too much for a
2)It's hardly fair to say that religion has been the largest cause of death and misery across the world for all time. The estimated 72 million executed under Mao Ze Dong's rule, or the > 10 million under Stalin's rule far eclipses the misled people's mistakes during the crusades, etc...(not that it marginalises the stupidity of those actions)
Humans will not be free until they have stopped being afraid of death and the scare tactics used to control the weak religious minded, such as belief in heaven, hell, judgement day, etc. nothing good will happen. All are used as tools by the Leaders and Pontiffs to keep the masses in line.
Until the substitution of reason and thought for blind faith happens nothing will ever change.
There are plenty of normal people who believe in a religion of some form or another who aren't sheep. I happen to follow Christianity, but it doesn't mean when the Pope decrees that condoms are bad I follow along with it. Additionally, what won't change? Regardless of whether there is religion or not, people are still going to starve and be killed. Same goes for whether or not capitalism/communism/dictatorships/democracies/et
Which leads us to...
But honor the 2 biggest killers of mankind - the military class and religion as advancers of society? Fuck, no. They are the biggest millstones around the human condition.
While they may or may not have been the _greatest_ advancers of society, a few technological innovations have sprung out of millitarism, and there are people who have done good things in the name of religion. I would argue that greed is the single largest stumbling point for the human race. It's people's inherant greed which causes them to use anything within their grasp to crush the people around them.
Maybe it's just me though...
Re:Excellent (Score:3, Informative)
In earlier history, virually the only reason for engineering was for military purposes.
Military:
Bronse processes
Iron processes
Steal processes
Basic Physics
Boats
Radio Communication advances
Planes
Atomic Physics
Rockets/Space vehicles
Satalites
Computers
The Internet
Religion:
Architecture
Printing Press
Mathematics
Re:Excellent (Score:5, Insightful)
Re:Excellent (Score:2, Insightful)
Sorry to point out your error in "tense", but Bush it STILL a sick and twisted mass murder(er).
Re:Excellent (Score:5, Insightful)
Oh.... For a second I thought you were talking about airplanes, ships, computers, combustion engines, or encryption. You know, all those things benefiting you that were developed for the evil military.
Don't forget. That freedom you enjoy wasn't given to you for nothing. Military people are the ones who earned it for you. That's why this new technology IS for us, freedom, and peace.
Re:Excellent (Score:3, Insightful)
You know. I'd wager that about 98% of posters that complain about the Patriot Act never bothered to read it themselves. Do yourself a favor, and read it before ranting. You might even learn something.
Re:Excellent (Score:2)
Who exactly do you think "us" is? Perhaps you come from some poor and enslaved country where soldiers are not free citizens, but around here the military is us. Thanks to technology like this we keep our peace, and secure our freedom.
Re:Excellent (Score:2)
When I lived in Maryland the government there refused to allow me to register as a member of the Libertarian Party for over 20 years. I could not declare what I was politically. That's not the mark of a free country. In a free country, you woulds be able to declare yourself to be what you are.
In West Virginia, only registered Republicans and Democrats can be poll workers to over see the voting process. Anyone else need not apply. These poeple will soon have electronic vo
Re:Excellent (Score:2)
In the US soldiers are used in civil matters, e.g. Waco.
Keeping our peace seems to entail invading other countries.
Freedom is only measured in the size of your cage.
Re:Excellent (Score:2)
Is that helping us?
I think so.
My Story (Score:5, Interesting)
Re:Purposeful Flame War post (Score:2, Funny)
Slashdotted (Score:5, Funny)
I'm curious... (Score:2)
Re:I'm curious... (Score:2)
A normal jet engine sucks in air, compresses it with several large turbines, adds fuel and ignites it. In a ramjet the air is compressed by the motion of the engine through the air, think basically a tube that tapers inwards. There are no moving parts, the fowards motion of the unit itself generates the compression.
Problem is, this doesn't work at supersonic speeds. A scramjet is ramjet shaped to work with supersonic air flowing throu
Impressive technically but ... (Score:5, Insightful)
I find the old crappy 1969 b/w pictures of the first man on the moon much more appealing than the Spirit panoramas, yet the probe went much further than Armstrong, and probably did a lot more science. But still, it's not the same thing, and NASA should send actually people up-diddly-up instead of drones, just because (1) there would be volunteers and (2) they would strike the public's imagination and generate sympathy for that kind of research, which in turn would turn into funding...
Re:Impressive technically but ... (Score:2, Insightful)
Re:Impressive technically but ... (Score:5, Funny)
Re:Impressive technically but ... (Score:3, Insightful)
Since NASA invented the astronauts, as a group of flyers somewhat distinct from USAF personel, and especially since they started sending civilians
Re:Impressive technically but ... (Score:2)
I dissagree. Perhaps it doesn't make the uninteligent kids dream like it "used to" but that's of little consequence. I think the smart kids DO get it and are inspired to go into science by those panoramas from Mars. They're the ones who'll go on to develop the next generation of missions
Re:Impressive technically but ... (Score:2)
Re:Impressive technically but ... (Score:5, Insightful)
Re:Impressive technically but ... (Score:3, Insightful)
Perhaps when enough people have died (sadly), whatever that number is, they will realize the importance.
Then, maybe then, we'll be able to declare a war on space...
Re:Impressive technically but ... (Score:5, Interesting)
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.
Re:Impressive technically but ... (Score:3, Funny)
I think this automatic control system [nasa.gov] is very close to being perfect AI. It's doing a great job of impersonating a pilot that's had a 3 beer lunch.
Re:Impressive technically but ... (Score:4, Insightful)
I can see where a human flight would create these things. But i personally consider it worth even a single person's life to remote test these things for safety. Once they are tested by remote, then humans can fly them too! and no one will die.
The same results (getting public attention and getting money) would be achieved by a successful man(or woman)-powered flight. While a death on a maiden flight often provokes sympathy, it is short lived. A successful flight, one achieved after the testing, createds longer lasting funding and interest. For instance, you recall the "old crappy 1969 b/w pictures of the first man on the moon". when asked about spaceflight this is what most people will recall - not the challenger blowing up. the man on the moon is our inspiration.
Therefore, to get to the point, if we can use a scramjet to do something awe-inspiring, like going higher cheaper than ever before and perhaps leading the way to cheap earth-to-space travel. sometimes safe isn't always exciting at first, but the end results are always the most spectacular.
Re:Impressive technically but ... (Score:3)
It was never the other way around.
Scramjets won't get you to space. (Score:5, Insightful)
Any airbreathing technology suffers a couple of fundamental flaws when it comes to suborbital, let alone orbital, transport. Most obvious, the air is mighty thin up there -- so you've got to stay where the air is thicker to support combustion. (Which basically means you can't make orbit with out at least some kind of apogee kick rocket).
Secondly, pushing through all that air creates drag. Now, you either aggravate the problem by slowing the relative airspeed enough to support combustion -- meaning increasing the drag on that air (supersonic combustion alleviates this somewhat), or you don't slow it down (relatively, actually you're speeding the air up), have a harder time maintaining combustion, and more significantly, have a much lower momentum delta in the exhaust -- meaning less push to the vehicle.
Scramjets have some limited use for high speed short range flight but rockets are far more efficient and the only practical way to get to orbit.
(And while I may not be a rocket scientist, I've had long talks about just this with some very expert rocket scientists, such as Max Hunter.)
Re:Scramjets won't get you to space. (Score:5, Interesting)
Re:Scramjets won't get you to space. (Score:3, Interesting)
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.
Re:Scramjets won't get you to space. (Score:3, Informative)
Sure, the fuel has a positive ROI on its energy budget--but that's not the whole story. You also have to lift the tanks, insulation, and pumps.
You'll note that they accelerate the damn test article with a rocket.
Why is this a strike against scramjets? By definition, they only operate at supersonic speeds. If you're trying to prove the concept there's only a limited number of w
Re:Scramjets won't get you to space. (Score:3, Informative)
Re:Scramjets won't get you to space. (Score:5, Interesting)
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
Re:Scramjets won't get you to space. (Score:2)
Re:Scramjets won't get you to space. (Score:3, Informative)
Thank you, at least somebody recognizes that.
If you throw cost into the deal, rockets fall apart. They're disposable for the most part.
They don't have to be disposable. The X-15 was a fine example of a reusable rocket -- 199 flights for the 3 vehicles, several of them high enough to earn the pilots their astronaut wings. That was 40-50 year old technology. The DC-X was a great example of a reusable rocket that could take off from t
Re:Scramjets won't get you to space. (Score:3, Informative)
Scramjets don't push through the air. They suck it in for combustion.
Horses were still the only practical means of getting around when the first steam engines were being developed. Times change. Technology improves. Chemical fuel rockets will one day be considered as archaic as steam engines.
Re:Scramjets won't get you to space. (Score:3, Informative)
ROFL!
That is just wrong on so many levels. You do realize, don't you, that it is impossible to suck air to a speed greater than Mach 1? (Well, unless you're sucking it into a huge vacuum chamber through a DeLaval nozzle, but only until the pressures equalize, and then only in the divergent section of the nozzle.)
Chemical fuel rockets will one day be considered as archaic as steam engines.
We all look forward to that day -- but air-
Re:Scramjets won't get you to space. (Score:4, Insightful)
- Proving the earth wasn't the centre of the universe
- Moving faster than a horse
- Flying
- Man landing on the moon
- Most likely, rub sticks together to start fire
If people listened to every expert who said something is impossible we'd still be in caves.
maybe one day (Score:5, Insightful)
Re:maybe one day (Score:2)
Is it worth it? (Score:5, Insightful)
Re:Is it worth it? (Score:3, Insightful)
Wheras with space vehicles... if someone wants to get something into space or do something in space, they have anywhere from zero to two options. Also, we don't yet know how economical space travel will eventually become because we haven't had as much time to develop it. And in the meantime, we have mainly governm
Re:Is it worth it? (Score:2)
Australia did it first (Score:5, Informative)
Re:Australia did it first (Score:2, Informative)
The US Defense Advanced Research Projects Agency performed the first successful ignition of a scramjet engine during a ground-based test in September 2001. This involved using a gun to fire the engine to a speed above Mach 5.
It reminds me of (Score:2, Funny)
Hypersonic British buses (Score:2, Funny)
When you do a google search about "X43" [google.com], although you get a page in the "Science > Technology > Space > Launch Vehicles" category [google.com], the first result is about the bus service between Calne and Marlborough [carlberry.co.uk].
Star Wars.. (Score:4, Funny)
scramjet ignition (Score:4, Informative)
Scramjet technology began around the 1950's. It has been since the 1970's research in to plasma torches in supersonic flows. The plasma torch servers as an igniter and combustion enhancer. Plasma torches offer a couple of advanrages. The plasma torch servers as an ignition source for the fuel and combustion enhancing radicals produced by the plasma torch.
Scramjets also use the hypersonic shock wave for compression. A high compression "point" is where the forebody and engine fence shock waves cross. One of the problems faced it is how to design the inlets to maximise the compression. To keep things simple many scramjet engines are designed as 2D engines.
Designs my attempt to use air stream swirl to enhance fuel and oxidizing air mixing.
For more details please see http://citeseer.nj.nec.com/cache/papers/cs/3623/ft p:zSzzSztechreports.larc.nasa.govzSzpubzSztechrepo rtszSzlarczSz1998zSzaiaazSzNASA-aiaa-98-2506.pdf/r ogers98experimental.pdf
Re:i was dumbstruck for a second (Score:4, Informative)
Re:i was dumbstruck for a second (Score:2)
NeoThermic
Re:i was dumbstruck for a second (Score:2)
Re:what the heck is scramjet (Score:4, Informative)
Supersonic is Mach 1.0 to 4.9, Hypersonic is Mach 5.0+. I'm not an aerospace engineer, but I vaguely remember an article in Popular Science that talked about how over Mach 4, the airflow through the engine would disrupt combustion.
hypersonic is above mach5 (Score:5, Interesting)
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.
Re:hypersonic is above mach5 (Score:2, Insightful)
Re:The engine's only the first problem... (Score:5, Informative)
The SR-71's fusalage expanded from heat, true. The material is going to have to deal with heat, true. The NASA shuttle deals with the heat of mach 25 on re-entry, and it is not torn apart by drag unless something goes wrong, but the same happens when a commecial airliner gets seriously out of shape in-flight. Like the one that lost its rudder over Long Island Sound a couple years ago.
The stealth bomber (B-2) is subsonic. Carbon fiber is used due to its strength-to-weight and radio-frequency transparency, not heat resistance. I would be looking at exotic metal alloys, metal composites, ceramics (which is what the space shuttle tiles are) and use of circulating fuel for cooling of critical areas. The flight profile for a long duration hypersonic craft would probably involve extended flight at altitudes where drag is less of an issue, further reducing friction heating.