NASA to Attempt Mach 10 Flight Next Week

Dirak writes "NASA intends to break its own aircraft-speed record for the second time this year by flying X43a scramjet ten times faster than sound. On November 15 the X-43A supersonic-combustion ramjet - or scramjet - will again take to the skies aiming for Mach 10."

Comments

What is the Speed of Sound?

[Anonymous Coward]

Just above the atmosphere, what is the speed of sound? I guess when an article says 10 times the speed of sound it means the speed of sound at sea level right? But this aircraft isn't at sea level. This aircraft skips on top of the atmosphere pulsing the scramjets while dropping into the atmosphere.

The speed of sound isn't a good tool to measure the speed, as the speed of sound without an atmosphere is either infinite, undefined, zero or a combination of the choices. I mean once you get into space, should you add the speed the earth is rotating plus the speed around the sun using a basis of sound?

Re:What is the Speed of Sound?

[Dr. GeneMachine]

You surely meant
In Space... No One Can Hear You Scram

Re:What is the Speed of Sound?

[bleckywelcky]

It's a record for an air-breathing engine. The SS get's lofted into orbit by self-contained solid rocket boosters that carry fuel and oxidizer together and burn it without air and then drops out of orbit. An air-breathing engine carries fuel with it and adds that to the surrounding air and pushes it all through it's combustion chamber.

Re:What is the Speed of Sound?

[ab762]

Precisely - Mach 1 is the local speed of sound. Specifically, it's the velocity at which shockwaves propagate. If you are flying at Mach 1 (plus delta) you are encountering a medium which is uninfluenced by your motion until you encounter it - it doesn't have time to get out of the way. That makes a huge difference to the behavior, a little like the difference between swimming in water and swimming in concrete!

There is, of course, a FAQ on this Frequently Asked Question.

Re:What is the Speed of Sound?

[kuwan]

The space shuttle isn't designed to fly like an airplane, it (like other rockets) are designed to get you into space. If you'll read a little more of the article:

The accomplishment will be included in the 2006 Guinness World Records book, set for release this time next year, as follows:

"On 27 March 2004, NASA's unmanned Hyper-X (X-43A) airplane reached Mach 6.83, almost seven times the speed of sound. The X-43A was boosted to an altitude of 29,000 m (95,000 ft) by a Pegasus rocket launched from beneath a B52-B aircraft. The revolutionary 'scramjet' aircraft then burned its engine for around 11 seconds during flight over the Pacific Ocean."

...

The X-43A flight easily set a world speed record for an air-breathing engine aircraft. The previous known record was held by a ramjet-powered missile, which achieved slightly more than Mach 5. A ramjet operates by subsonic combustion of fuel in a stream of air compressed by the forward speed of the aircraft itself, as opposed to a normal jet engine, in which the compressor section (the fan blades) compresses the air. A scramjet (supersonic-combustion ramjet) is a ramjet engine in which the airflow through the whole engine remains supersonic.

The highest speed attained by a rocket-powered airplane, NASA's X-15 aircraft, was Mach 6.7. The fastest air-breathing, manned vehicle, the SR-71, achieved slightly more than Mach 3. The X-43A more than doubled the top speed of the jet-powered SR-71.

An airplane that goes Mach 10 will be an amazing achievement for an air-breathing engine (a.k.a. non-rocket) aircraft.
--
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Re:What is the Speed of Sound?

[AyeRoxor!]

Just like 1 Atmosphere is air pressure at sea level, Mach 1 is the speed of sound at sea level.

Interestingly enough, according to Google Math, Mach 10 is ~127 miles a minute. Assuming it takes them at least 5 or 10 minutes to achieve Mach 10 (I have no frigging idea), they are going to cover some serious distance. Sheesh.

At Mach 10, you will circle the Earth in under 200 minutes.

Damn I love Google math.

Re:What is the Speed of Sound?

[Jetson]

I guess when an article says 10 times the speed of sound it means the speed of sound at sea level right?

Mach "speed" is expressed as a ratio and is usually relative to the local environment. You can increase your Mach ratio either by climbing at a constant absolute speed or by accelerating at a constant altitude (although climbing at an increasing absolute speed works best :-P).

The problem with using altitude to improve your Mach ratio is that it decreases your indicated airspeed (the air felt by the wings). There comes a certain point with some high-performance aircraft where the indicated airspeed is just above stall and the Mach ratio is just below the aircraft's design limit. This is called the "coffin corner" because once you reach that speed/altitude it's virtually impossible to descend or slow down without losing control of (or destroying) the aircraft.

Rutan's Space Ship One solved this problem by intentionally stalling the aircraft in a stable high-drag attitude and staying in that configuration until safely back into the flight envelope.

To Bad for the sonic Boom.

[jellomizer]

All this extra speed will not be available for the common public until they can resolve the problem with the sonic boom. Once that is resolved I think it would be a lot more interesting where they could have supersonic flights that go over land as well. And the general public will advance. Right now having an airplain that can go at Mach 10 is somewhat useless because we can already out fly our enemies planes which most were build during the cold war times.

Re:To Bad for the sonic Boom.

[Cheeko]

I think there is little to no interest in this as far as combat aircraft. NASA's main interest is in using scramjets to produce aircraft like vehicles that can "fly" into space affordably. As I understand it aside from their ability to operate at high speeds more efficiently than rockets, they also allow for much higher altitude functionality than a standard jet engine. This would allow a space plane to get high in the atmosphere, then use a small rocket boost to get into orbit.

I believe the idea behind a functional vehicle would be something like a standard jet engine getting a craft up to mach 1 or 2, then a ramjet taking over and getting a craft up to mach 5 or so, and then a scramjet taking a ship up to mach 10-15, at which point a rocket boost pushes it through the last bit of thin atmosphere into orbit. I may be wrong, as my knowledge on this was material read 4-5 years ago, but that seems to be what I remember.

Supposedly a nother great thing about scramjets is their simplicity, very few moving parts, which allows for high reliability. Or as high reliability as can be expected for something working under the strain of Mach 10.

One step closer to

[jaguar5150]

Ludicrous Speed!

Final Flight

[SimURL]

If successful it would be a great accomplishment. However, according to this Wired article
http://www.wired.com/news/technology/0,1282,65671, 00.html?tw=wn_tophead_3,
NASA is "phasing out its hypersonic engine program to free up funding for President Bush's 'Vision for Space Exploration,' which calls on NASA to focus its energy on sending humans to the moon and Mars."

Therefore,
"As of now, next week's X-43A flight is the final flight in the $230 million program."

I can't help but wonder if these priorities are correct as I'm not quite sure what we intend to do after we reach the moon and Mars.

Blackbird and the Swedish fighter Viggen

[3770]

The U.S. Blackbird spy plane was _really_ fast when it came out. It is still probably one of the fastest aircrafts out there. Maybe still the fastest.

The Swedish fighter jet, Viggen (which is built by SAAB) was the first fighter plane to ever get a "lock" on the blackbird.

The Swedish radar systems got it on radar. The Viggen flew to intercept it with after burners on the whole time.

It got a lock on it and then had to turn back because it was out of fuel. There was of course never any intention of firing a missile, but still.

The black bird crew sent a box of chocolate to the Swedish air base and said "Congratulations!".

At least, this is what I heard. Whether it really is true, I couldn't tell you for sure.

This is what NASA is meant FOR

[Thud457]

People, people. This is what NASA should be doing. Basic aeronautical research.

Then some smartass hillbilly with nine-inch sideburns can make use of their research to build a rocketplane and proclaim : "Spaceship 2, Government 0"!

Rockets vs. Jet Engines

[hey!]

Yes, but the shuttle is launched by rockets, not jet engines.

I am not an aeronautical engineer or even much of a space buff by /. standards, but my understanding of the situation is that rockets carry both fuel and oxygen, whereas jets carry just fuel and breathe oxygen from the atmosphere. What I think this means is that to the degree you can get the speed you need to access space using a jet in the atmosphere, you can dispense with carrying some of the oxygen.

Again, in my naive, non expert way, I look at a typical rocket and see a huge cylinder of fuel and oxidant with a teeny tiny payload on top. Even a marginal reduction in the size of the non-payload part has got to make a big difference in cost per pound of payload. I'm guessing this is leading to systems in which the first stage to orbit consists of a reusable scramjet powered vehicle that takes the next stage above the atmosphere.

Aviation Technology Week's take on Scramjet

[DumbSwede]

On the downside I read a recent Aviation Technology Week that states that the Mach 10 flight is the end of current funding for Hypersonic Flight research. Evidently there are not concrete plans to keep going even if this flight is a success, though it seems unlikely NASA would let the program die completely (like other X projects).

Also stated in the ATW was that there wasn't (or shouldn't) be any animosity between the Scramjet team and the Rocket technology teams, in that affordable scramjet is projected to top out in the 20,000 lbs to LEO range and have a $1,700 per pound price tag vs $2,200 for expendable rocket, but with rocket being able to heft much larger loads. Still, the 20,000 lbs range is projected to meet 80% of future lift needs.

This figures struck me has oddly pessimistic, but they see problems scaling with this technology. They think the real advantage to scramjet will be reliability, with current unmanned failures rates (and manned it would seem also) at one in 50, and scramjet figured at 1 in 4000 or so (assuming a return to Earth on propulsion failure). Of course the Shuttle was projected to have a low failure rate also.

Still I would think a four-tier approach would be near ideal for now.
Maglev assist takeoff to Mach 1 or 2
Jet assist to Mach 3 or 4 (stubby winged, high-speed, jet wouldn't have enough lift for loaded takeoff on it's own)
Scramjet to Mach 8 or 10
Rocket final stage to Mach 22 orbit.

Maybe Congress doesn't want to fund this because they're misreading Scramjet as Scam-Jet.