Before the space shuttle is retired, as eventually it must be, could it be used for a manned mission to the Moon.
I envisage a plan something like this:
One shuttle launch carries an extra fuel tank into Earth orbit. It is something like the external fuel tank used on all shuttle flights, only small enough to fit into the shuttle’s bay.
A second shuttle is launched at a later date. It docks with the small fuel tank. Maybe a space walk will be required to make the necessary fuel pipe connections for which the shuttle was not originally designed, I guess all that can be worked out.
All fueled up, the shuttle heads for the Moon. When it get there, two or three of the crew transfer to a landing module stored in the shuttles cargo bay - much like that used on the Apollo missions. The crew land on the Moon, have a bit of look round, play some golf etc. and then return to Lunar orbit. They dock with or space walk to the shuttle.
Shuttle returns to Earth, jettisons its external fuel tank and lands as per usual.
Even if a mission like this is not possible, could the shuttles usefully be retired in orbit to be used as workhorses of some sort. Given that a shuttle replacement is likely to be rather smaller than the shuttle, they may be able to do some jobs that could not economically be done any other way. Of course, a shuttle cannot be serviced while it is in orbit, but the stresses of manouevering in space are slight compared to those of blasting off from the Earth’s surface - so one might expect a resonably long useful life. Any thoughts?
Hmm. I suppose you could leave a shuttle docked with the ISS to serve as a lifeboat (just make sure it’s kept in good enough shape for at least one landing, or at least stocked with enough cheetos and soda to last until a rescue mission can get to it) or something.
Otherwise I guess it could be used as a small orbital storage shed, with various equipment or supplies kept in the cargo bay and parked in orbit somewhere that it can be easily gotten to. Dunno how practical this would actually be though.
I suspect the shuttles would make poor orbitals for a variety of reasons:[ul]They are not designed for long term endurance in orbit. This means, for instance, that they don’t have to be rated for long term exposure to monotomic oxygen, radiation, etc.They’d have to be retrofitted with either a reactor (conventional or RTG) or solar power systemThey’d have to have a refueling system installedI’m not sure what impact long term station-keeping would have on the systems, but I suspect that the computers would have to be replacedAn emergency descent/rescue system would have to be designed[/ul]And those are just a few things I can think of off the top of my head.
Another big problem with this plan is the way the shuttle is designed to land. It first sheds most of its velocity via air resistance, then it glides the rest of the way to the runway. For both phases you need a nice thick atmosphere like the Earth’s.
Homer Hickam, an ex NASA flight ops specialist (and the author of Rocket Boys, which was turned into a great movie called October Sky), wrote a novel that posited a shuttle being sent to the moon. As I recall, it involved attaching another engine and fuel tank to it in orbit, plus other bits like a solar shield. Far-fetched, of course, but perhaps possible in a thought-experiment kind of way.
Certainly a Shuttle could not make that trip unless heavily modified.
Interestingly, one of the original plans for going to the moon, proposed by Werner Von Braun, was called “earth orbit rendezvous” and involved using a few rockets to assemble a spacecraft in orbit around the earth, and then sending it off to the moon. This craft would have had to be huge, carrying enough fuel to go to the moon, land, and get back, while being big enough to re-enter earth orbit without burning up. Of course, the bigger your lander is, the more fuel you need to lift it, which adds weight, etc.
John Houbalt (sp?) was one of the few guys at NASA early on who realized that “lunar orbit rendezvous”, where you send a tiny lander down to the moon and then re-dock with the ship to get back to earth, was a more practical way.
A lot of the problems I mention are still concerns. The shuttles are designed for operation in low Earth orbit, and so are not shielded nearly as heavily as a Moon-shot craft would be. Radiation and dust would be a problem. The communication gear is probably not adequate, either, which would require a major refit.
I’ve heard that the shuttles would have enough juice to make a Moon orbit if they were completely refueled once in LEO, but I’m not sure if anyone’s sat down and done the math. It takes an enormous amount of delta-V to make it to the Moon, even from LEO. If you’re not intending to let the shuttles land, you have to have a lot of extra fuel to slow them down upon their return to Earth orbit.
In Apollo, though, you get most of that juice from the rotation of the Earth; essentially, you use the SM engine to put you into a highly elliptical, minimum energy orbit that not only intercepts the Moon but does so at a velocity that is very similar, so that a small adjustment allows you to enter a Lunar orbit. Ditto on the way back.
As for the Shuttle, a Lunar jaunt is not in its conceptual mission profile; however, given an adequate amount of fuel I don’t see any reason it couldn’t reach the Moon, though you’d definitely need to boost the Shuttle into a higher orbit than LEO, which would take quite a bit of extra delta-v. The SMEs are restartable and generate considerably more specific thrust than the Apollo SM. On the other hand, losing speed via aerobraking might be tricky; a Lunar return path has considerably more energy than a descent from LEO, and the Shuttle’s heat protection systems may not be up to task. Other issues regarding crew survivability and protection against radiation are concerns, but Apollo wasn’t especially well-shielded against radiation either, so I doubt a Shuttle couldn’t be modified to perform the mission.
Whether it would be efficient to do so is another matter. With the Shuttle you’d be taking along all the extra weight of the lifting body to no good purpose. You’d have to build a dedicated mission module in the main bay to store and support your lander. You’re going to have to come up with some kind of fuel transfer method and equipment, which is definitely non-trivial; the Shuttle was never intended to be refueled or take on additional external tankage in orbit and has no provisions to do so.
As for using the Shuttles as “workhorses” or orbiting storage lockers…sure, you could, but why would you? Again, you’re dealing with a lot of extraneous weight and complexity for a simple orbital tug, and as the Shuttle was not intended for long duration missions there would no doubt be considerable maintainence.
Then there’s the theft and vandalism problem; they don’t make The Club for the Shuttle. How do you stop some of those wacky Chinese sinonauts from taking a joyride?
no way. I am not a rocket engineer, but note that the space shuttle isn’t equipped with fuel tanks for the main engines.
I haven’t done the calculations, it would take quite a while for me to do them :), but I am certain that there is no way the shuttle could ever leave earth’s orbit. Even if you tied tanks to the shuttle (and how would you get them into orbit in the first place), you couldn’t possibly put enough fuel on the shuttle to overcome the tremendous dead weight of the heat shielding.
Even after all the physical impossibilities, NASA long ago realized it is far too dangerous to ever store significant amounts of rocket fuel near the space station.
Well, technically, yeah it could. But the amount of work you’d have to do modifying the Shuttle to do the job puts you in the same ballpark as “Could a Greyhound bus be used for a manned mission to the Moon?”
I’m sure there’s a lot more, but I’ll point out two areas where you’d have problems.
First: The Shuttle Orbiter weights about 185,000 pounds. Add in an Apollo Lunar Lander at about 35,000 pounds.
Now, even assuming no other extras, you’ve got 220,000 pounds to send to the moon. That’ll need in the area of 330,000 pounds of fuel to get you there, not the 65,000 pounds payload capacity of that first launch. So you’re going to need six preliminary launches just to orbit the fuel (gotta figure in those six fuel tanks). Now, you can’t just use this to “fuel up” the Shuttle. It’s got very little internal fuel capacity (about 18,500 pounds of hydrazine and nitrogen tetroxide) to be used by the orbital manoevering system. Remember, the fuel used to get the Shuttle to orbit is stored in the large External Tank that’s jettisoned just before they get to orbit.
Second: The Shuttle’s heat tiles are designed to hold up to the temperatures of entering the atmosphere at Earth orbital speed, about 18,000 mph. Coming back from the Moon it’d be hitting the atmosphere at about 25,000 mph. The tiles wouldn’t be able to stand the additional heat.
And you can’t just carry along some extra fuel to slow you down. To slow from the 25,000 to the acceptable 18,000 mph would require the same amount of fuel used at the beginning of the trip to accelerate from orbit to lunar trajectory: about 330,000 pounds worth (well, not quite as much - you presumably dumped the Lunar Lander once you were done with it). Anyway, to get that 330,000 pounds of fuel all the way to the moon and back would require an even bigger fuel load at the beginning…
The Apollo Saturn V rocket was able to put about 100,000 pounds into Lunar orbit (the Lunar Lander and the Command/Sevice Module). They were only able to make it work at all by going to extraordinary lengths to limit weight. Carting along ~100,000 pounds of wings, cargo bay structure, landing gear and Shuttle main engines - none of which is of any use for your trip - is a waste. If you’re going to take along that much, make it 100,000 pounds worth of supplies and equipment that can be used to set up a lunar base.
The cost of all this would be pretty large. Just the cost to launch it all into orbit runs into the Billions. On top of that the cost of all the modifications, designing and testing new equipment. There’s no usable Lunar Lander just sitting around either, so they’d have to build a new one. They were very specialized vehicles, and took a lot of specialized machinery, tools and knowledge to construct - all pretty much gone now. You can’t just dig out the blueprints and crank one out. Re-creating it all would be nearly as much work as creating them the first time around.
If they wanted to develop a new modern 21st century Command Module and Lunar Lander and have them put into Earth orbit by the Shuttle, maybe it’d make sense. But it’d still take two launches just for the vehicles themselves. You’d still need to get some kind of booster up there to send the whole thing on the way to the moon.
But taking the Shuttle itself to the Moon? Nope, it makes no sense to go to all the trouble to turn a spacecraft designed for one specialized purpose into one designed for a radically different specialized purpose.
Once again, you’d be carting around a lot of useless weight. If you just want something to cruise around in orbit, construct the station or a future manned Mars spacecraft, maybe go out and repair damaged satellites, then a 185,000 pound Shuttle is way overkill. They could do the job with something a tenth the size. It may seem economical to re-use the Shuttle rather than a purpose-built vehicle, but it wouldn’t end up that way. Pushing around 150,000 pounds of dead weight in orbit would use tons of unnecessary fuel. That’s fuel that you’re spending thousands of dollars per pound to bring up from Earth. Tha’d get real expensive real fast.
Note that it was not the Service Module that was used for trans-lunar injection, but the third stage of the Saturn V. The Service Module was only good for lunar orbit insertion and trans-earth injection, much lesser tasks. The rest of your sentence confuses me, but I guess it isn’t too far away from what I’d say:
“You used the third stage to acheive a trajectory that takes you around the backside of the Moon and back to Earth with no major thrust needed. Since the moon is so small, you just need a little delta-v to get into lunar orbit and back out into a return-to-Earth trajectory.” Or something like that.