Astronauts Face Bleak Odds For Spaceflight 359
Abhishek writes "According to a Space.com report, Astronauts at NASA fear that they won't be able to fly until 2015 and that, for some, would be too late. The space shuttles that NASA have are almost at the end of their lifetimes and any shuttle can take years to be built. Though almost everybody is involved in some way or another in looking after a shuttle, only a lucky few actually gets the chance for a ride."
While waiting for specific mission assignments... (Score:2, Informative)
They help with planning and ground support for other missions, help with long-term planning, and serve other tasks often depending on their pre-astronaut background.
Currently, there are some working on the Crew Exploration Vehicle and Moon/Mars plans.
Re:Begs the question... (Score:5, Informative)
Most of them have other jobs at NASA when not in prep for a flight, such as running a lab, program manager for a particular system, performing various analyses or engineering work, etc., plus all the PR (trips to schools, educational programs). Basically their technical/leaderhship skills are used within the program.
Well, if they want to go into space they can always take one of the new private rides which will probably get them there faster than 2015, though not for as long a stay.
Re:hmm (Score:5, Informative)
Re:Begs the question... (Score:4, Informative)
Re:Begs the question... (Score:5, Informative)
That is begging the question. ;)
2 jobs (Score:5, Informative)
Excerpt from RedNova [rednova.com]
Re:What do you call an astronaut who won't fly? (Score:3, Informative)
Uh, first, we have to have private spacecraft. Burt Rutan's project is about at the level of the second Mercury flight, which was suborbital.
Definition of an astronaut? (Score:3, Informative)
" a person who travels beyond the earth's atmosphere; also : a trainee for spaceflight"
Gotta suck when you tell people you're an astronaut and people's first question is "When did you go up?". They probably have the Websters definition loophole printed on the back of their business cards.
Re:Begs the question... (Score:5, Informative)
Getting into space is more complex than flying an airplane up to 63 miles and jumping out. To go into orbit you need to achieve a speed of about Mach 25 (Spaceship 1 was nowhere even close to orbital velocity). Rocket technologies today make sense in accomplishing this by minimizing the weight of the spacecraft and maximizing the weight of the fuel. To do what you want would require that almost all of the fuel and useful spacecraft are carried in an aircraft to perhaps 100,000 feet. The fuel to do so would be enormous and you would still have to fire the rocket to get the other Mach 24 or so. The complex airoframe required to pull this off would probably require a significantly larger amount of fuel that is used today. The losses a rocket has from atmospheric drag at high velocities (up to about 100,000 feet to be equivalent) would be vastly smaller than the fuel required to launch a standard airplane assisted rocket launch.
On a side note, a scramjet may be useful in the future due to its small engine size (extremely few parts). In this scenario a rocket would launch from the ground up to Mach 1, the scramjet would accelerate up to Mach 15, and then another rocket would accelarate up to Mach 25 for orbit or escape. Considering that no space launch has ever used a scramjet, I don't think its fair to call existing technologies 'dumb'. But then again, when has anyone considered 'rocket scientist' to be a synonymn for 'intelligent engineer'?
Re:Begs the question... (Score:5, Informative)
What the parent needs to realize is how tough it is to scale up rockets to orbital, because you have to invest more and more of your energy into accelerating your fuel. It is quite possible, in theory, to get a moderate cargo to orbit from air launch (tow-launch, drop-launch, or carry-launch) if you use very high ISP engines and a very low mass craft. However, if you don't, your ability to just drop from an aircraft quickly becomes untenable; even a Cossack couldn't carry, say, a scaled-up SpaceShipOne.
The real benefit from air launch, BTW, is not the altitude, but the fact that you don't have to plow through the atmosphere as much and don't have the problems associated with having your engines firing right near the ground (which is more likely to damage them). And ramjets would be great; unfortunately, we cancelled the program because of the premature Mars mission spending
Re:hmm (Score:3, Informative)
Re:Begs the question... (Score:1, Informative)
Right place, right time (Score:3, Informative)
Everyone in the Astronaut training program is looking for their chance to jump the line and get wings, and you never know how might turn out to be the one to flip the critical switch for SCE to AUX and save the mission.
Bean later flew in space again as a Commander on the Apollo Applications mission that became Skylab.
Re:All of this overlooks one interesting item... (Score:1, Informative)
vf^2 = vi^2 + 2 * a * x
since vi = 0, vf = 330 m/s * 3 (speed of sound * 3 for Mach 3), and x = 50 m, then a = 1089 m/s^2, or 110 G's. Your spacecraft wouldn't survive that much force. To bring it to a 'safe' 10 G's, your catapult would have to be 555 meters long! Possible, but probably not practical. For a 50 foot catapult you would be talking about 1000 G's for Mach 3 flight. For a 10 G flight you would be talking about a catapult length of 5000 meters.
Re:The "Excess Eleven" (Score:4, Informative)
"Most of those guys quit or were laid off in the early 1970s."
From the article:
"Seven stayed on through the 1970's and finally got to fly aboard the space shuttle."
In reality most stayed on and actually got to fly.
Re:Begs the question... (Score:3, Informative)
Err... no. The program was cancelled because scramjets are useless for launching cargo into orbit. The problem is, as you pointed out earlier in your post, the majority of the energy you need to get to orbit is in the "horizontal" direction. Most orbital flight profiles expend only 10% of energy getting into space and 90% gathering enough speed for orbit.
What that means, in practical terms, is you lose too much energy to drag friction to make accelerating in the atmosphere worthwhile. You're better off just bringing the oxidizer with you.
And there are three more practical problems to deal with. The first is all the extra complexity you need to get up to speed. A scramjet doesn't work until the craft is already moving reasonably fast (OK, that's weaseling, but "reasonably" depends on the design). So you'll need some kind of rocket booster to get it going even if you're at altitude. No big deal, right? Well, it turns out separating from a booster in the atmosphere is a big deal (I believe that's what caused the first scramjet test failure). This would be a major source of complexity (and thus cost).
The second problem is materials. All that drag is gonna create a lot of heat, and your craft had better be able to deal with it. On top of that can you imagine going through an air pressure differential at mach 20? So your ship has to be able to withstand plasma temperatures and it has to be incredably tough.
Also, the intake configuration of your scramjet is heavily dependent on air density. So it only works in a very narrow range altitude range. Too high and you don't have enough oxygen for combustion, too low and you burn up from the air friction.
As near as I can figure, scramjets have only one application: long range, high altitude air-to-air missiles.
And the point here is what? To build a smaller rocket. Why not just build a bigger rocket? The price of the fuel is just a tiny fraction of your launch cost, so just use more of it. The cost driver for rockets is complexity, not materials.
The best solution would be a reusable VTOL rocket (not rebuildable, like the shuttle) It would require a very large rocket, since the ratio of fuel to cargo is large. But that would allow you to use the same rocket over and over without rebuilding it, since landing is virtually stress-free (from an engineering perspective) compared to the shuttle. See here [jerrypournelle.com] for details.
The DC-X project was our best hope for cheap access to space. The project had demonstrated the technology involved with vertical landing, and would have evolved into a vehicle you could use over and over with only minor inspections between flights (as opposed to tearing it all apart, inspecting everything, and putting it back together).
But NASA killed it because they couldn't fund both it and the shuttle, and the shuttle was already proven technology in the sense you could already fly it to orbit and land it, while DC-X would have required a few iterations to make it work properly.
It's no coincidence Carmack chose the design he did, and he could probably get to orbit reasonably soon if he wasn't trying to fund the whole thing out-of-pocket.