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NASA 'Hyper-X' Series Scramjets
swight1701 writes "Sciencedaily.com is reporting that NASA has revealed its plans for developing Hypersonic aircraft within 2 decades. These plans include planes that could routinely go Mach 5+ and capable of taking off from an airport and visiting the IIS, or for you earthbound folk, from one airport to any other within 2 hours. And you thought your luggage gets lost NOW.:)" NASA's release includes some graphics showing what the test vehicles look like.
Has anyone else noticed the lack of windows (as in glass) for the pilots?
Perhaps since they are developing hypersonic aircraft, they will scrap the X-4000 Launch Aparatus. I hope they have better luck with these these aircraft than they do with Mars probes.
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If I want to visit the IIS, I'll just go into the computer room, thank you. Oh, you mean the ISS...
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My GOD! That thing is HUGE! In that first picture, you can see the artist's concept of the thing about to swallow a B-52!
Don't Bogart the fish sticks
Another way is to build the rocket engine into the Scramjet but that's much more difficult.
At those speeds, wings are a hindrance. One finds that the leading surfaces must be made of unobtanium.
The correct model for spacecraft is to take off and land on a tail of fire, as God and Robert Heinlein intended. The DC/X proved that; 11 successful test flights, including an 11-degree 'walking tilt', before NASA took over that program and (deliberately?) crashed the prototype on their first try with it.
Look at the early days of NASA. They sure blew up a lot of rockets then. I recall one book claiming someone quipped that if the first model didn't blow up on the pad, there was something nasty and unseen wrong with the design. (If it blows up it's still wrong and nasty, but at least you know to look for something amiss.)
But now rockets tend to get the job done more often than not. This new thing might be 'an airplane' but it's still a new thing and new things tend to not work the first time. There's process called learning involved. Sometimes, alas, it is terribly expensive.
I don't subscribe to RMS's GNUtopian vision.
Probably not. The problem is you need extra equipment to breath the air- and you carry that all the way to orbit. It turns out that's really critical- you gain most of your speed as the tank is running out (because your fuel level is low and the vehicle is really light then, so you get better acceleration per unit of fuel at that point). And you're in a vacuum, so this equipment doesn't help at all at that point.
Adding in extra mass for airbreathing means that the latter part of the launch is messed up- and so the designs to do this have not succeeded well- they end up using more fuel not less, and/or the payload ends up being really tiny.
Also, you're probably solving the wrong problem- the fuel is less than 1% of the cost of building and launching a space vehicle.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"The flying tube really hasn't had much design change for the past 50 years. Oh, I forgot, "Winglets, yay!"
My God, it's Full of Source!
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How is this going to affect the ozone layer in the future, if hundreds of these things are flying through it every day?
Just some ideas.
ALSO: How come we don't see postings on Nasa websites with "what we've considered and why it didn't work" so outside engineers can solve their problems for them...
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So they want to build a plane that files in atmostphere at mach 5+?
Lets think about the plane that closest fit the bill, the SR-71.
It was capable of mach 3+ and flew at an altitude of ~120,000 ft.
It was made completely out of titanium and the body of the plane got so hot that the pilot had to wear a space suit and couldn't touch the cockpit glass. The plane leaked fuel on the tarmac because it had to be designed with gaps that would close once the frame expanded from the extreme heat. In order to maintain mach 3, it had to run at full afterburners, burning a special fuel that had a super high temperature of ignition. And this was so it could carry 2 guys and a camera.
See the problems I have with this? Now granted, I'm not an airanotical engineer by any stretch of the imagination (or literate for that matter, based on my inability to spell...)
It was hard enough to get a moderately large plane going mach 3, now imagine what kind of energy you'd have to exert to get something the size of a 737 going?
Just my thoughts...
Yes Francis, the world has gone crazy.
it has been my understanding that fuel is the major cost of launching a space vehicle. Or at least the root of the problem. The shuttle itself is reusable, so a minimal amount of money is used to get it flight ready again. The SRB's are reuseable, but must be refueled with solid rocket fuel. However a new External Tank must be constructed for each launch. That is the biggest part of the assembly.
The problem is that because the shuttle is man-rated, they basically have to take it apart and put it back together again to make sure everything still works. This costs a _lot_. Fuel is cheap, but shuttle parts and skilled engineer time are not.
A secondary problem is that the cost of maintaining all of the facilities for servicing the shuttle must be amortized over the (relatively few) shuttle launches. This too is very expensive.
The main reason why finding more effective fuels is important is that they let you reduce the total craft size and weight for a given payload weight. This makes the craft much cheaper to build and maintain, reducing the cost of lifting the fixed-weight payload.
Your numbers are a bit off BTW. The cost to launch a man is generally reckoned to be about $10,000 per kg. The russians charge less than $20 million, basically because they can. Their whole rocket costs about $5 million. There's a big difference between cost and price...
The real cost goes into the salaries of the employees. There's about 10,000 or more involved with the Space Shuttle. But don't get the impression that the Russian rockets are cheaper just because the Russians are paid a lot less- they are, that's a big factor, but the way they put their rockets together is more efficient as well. NASA don't seem to care about low cost in quite the same way.
Please don't mention the external tank... it gives me a headache just thinking about that much waste.
SLI? Hah!
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"About your cheap fuel point, you're missing the problem of weight. Yes, the fuel is cheap. Getting the fuel to 100,000 feet with a rocket is not cheap. Rockets are not the most efficient propulsion system. They are needed in space because nothing else works.
I'm not an expert. If you are, I'll concede the point.
Yeah, that can work. But then you've got a two stage rocket; which is messier. Anyway they already do that- with a normal jet- the Pegasus launch vehicle carries a rocket up and then fires it from there.
About your cheap fuel point, you're missing the problem of weight.
That's mainly an issue with ground handling I think.
Yes, the fuel is cheap. Getting the fuel to 100,000 feet with a rocket is not cheap.
Actually it probably is, it mostly just costs fuel, but fuel is cheap.
Rockets are not the most efficient propulsion system.
Thermodynamically a rocket is the most efficient propulsion system. It can turn practically all of the energy in the fuel into fast moving fluid flow. It's more efficient than jets because it runs at incredibly high temperatures. However, jet engines can get more total thrust ('impulse') per unit of fuel because they suck in the oxygen from the atmosphere. If you count that in; Jets are less efficient in fact.
I'm not an expert. If you are, I'll concede the point.
It's not that the idea is silly, it's just that the constraints on it are tight enough that nobody has managed to get it to work well.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"google cache You'll see the cost per kg of liquid hydrogen was $2.60 in 1980. I expect it has gone up since then, but not so very much; and it does vary a bit- e.g. if you order enough hydrogen the price goes down.
The Space Shuttle's main tank contains 101 tonnes of liquid hydrogen. Assuming a price of $5/kg, that's $505,000 worth of hydrogen (since there are 1000kg to the tonne). Right?
The cost of adding an extra Space Shuttle to the yearly launch manifest is about $200 million.
Congratulations, you have just learnt something!
Oh yeah the Space Shuttle also burns 606 tonnes of LOX. LOX costs vary, but they are typically a few cents per kg. You can multiply that up if you wish, but the costs are more than 10x less than the hydrogen.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"