Future of Space Shuttles - How could the Space Shuttles be used?

Mark S · 2002-04-20 22:59:41

On the contrary, I believe that international cooperation has made space even more expensivve than each county doing things independently. The ISS has been delayed and gone over budget because the partners were unable to keep up their end of the agreement (Russia has no money to build modules on time, the U.S. will not pay for the Transhab, etc.)

I also think that conventional rockets will be prohibitively expensive. Most of the fuel weight (and thus cost) is liquid oxygen, which is carried insie of the rocket instead of being drawn from the atmosphere. Once we can create air breathing rockets like the National Aerospace Plane or the Andrews Alchemist, we can reduce the cost of space launch.

Vishal · 2002-04-21 04:29:42

1.
Liquid Hydrogen and Liquid oxygen are not the most expensive components of the actual launch vehicle and although air breathing is the best way for a future vehicle, my point is that costs are artifically kept high at the moment and its all the excessively extra staff, facilities and random other "required" costs that are putting up prices.

2.
a. International co-operation, for the sake of internatonal co-operation is pointless I agree as in the case of the ISS. I mean every module being attached to it is designed from scratch rather than using one standard design.

b. Though lets say no co-operation but buisness agreements are signed for example,, using the russians purely for the launch capability offered by Energiya... another group for the upper or interplanetary stages... one standard design for the actual hab modules... This prevents duplication of research and cuts costs. True it will be difficult as every group will try and claim if u have a"A" u must have "B" etc and piss a lot fo people off who are completely excluded from the partnership.. but hey space exploration should stop being a charity.

Phobos · 2002-04-21 12:53:00

I never mentioned anything that involved a cable going from earth to the moon. You are right, that idea is pretty stupid. Maybe Phobos got abit confused with what I said, but i'm pretty sure the neither of us were talking about a cable from earth to the moon. (the whole solar electric propulsion thing is the means of getting to the top of the elevator on the moon).

No, I didn't assume the Lunar elevator cable would be connected to the Earth. I meant it would be efficient in that you wouldn't need extremely heavy launch vehices to take a payload from Earth's surface to the Moon. Instead you could just launch a payload meant for the moon into LEO and from there hook the payload up to the lunar elevator. I don't know how anybody got the idea that I thought the elevator would be hooked directly up to Earth.

Mark S · 2002-04-21 19:51:10

Vishal, I agree about the high fixed launch costs associated with current launch vehicles. Take the Shuttle for example. NASA operates the Shuttle in a horribly inefficient manner. Because the Agency is a federal jobs program, it has no incentive to streamline operations. It has been suggested that shuttle operating costs would be decreased by a factor of ten if it was operated by a private company. I believe that a next-genaeration shuttle, designed for quick turnarounds, automatic health monitoring, and full reusability, would cut costs by another factor of ten. Only then will space tourism become a reality, and not a dream, for the masses.

AndyM · 2002-04-22 02:56:44

Hi RobHazlewood, assuming that the moon rotates about its own axis every 29 days, then a lunar geosynchronous orbit would be about 90,000 km above the moon's surface. This might be a problem as the elevator would extend out of the moon's sphere of influence (SOI) which extends to about 67,000 km. (For comparison, the SOI of the earth extends to 323,000 km with respect to the moon and to 920,000 km with respect to the sun.) The SOI is a measure of the region around a body in which its gravitational attraction is dominant. Granted, its only a qualitative measure and so it might not be a problem at all. I don't know...but its something to keep in mind. Of course, the problem of a lunar elevator could be simplified if you aligned the elevator cable with the axis of the earth-moon system.

Hi Phobos, just to clear up some points. The lunar elevator would extend from the moon's surface up to a lunar geostationary orbit. Thus, you would still have to travel from LEO to the lunar geostationary orbit (a distance of about 300,000 km) before you could hook up to the lunar space elevator. Have I understood your idea correctly, RobHazlewood?

Phobos · 2002-04-22 18:14:49

Yeah I think your right AndyM. I can get a little stupid with blind enthusiasm sometimes. It wouldn't make sense for that cable to reach clear to LEO.

Canth · 2002-04-23 14:05:33

The current space station design was actually chosen specifically to utilize the space shuttle. (According to Entering Space by Robert Zubrin) The space station was originally an American project and was later expanded to become multi national. The way it works now is you assemble it in space from pieces. However it is much cheaper to design a heavy lift booster and boost a station into orbit all in one piece. The reason they chose not to do this was to increase the number of space shuttle launches, which would decrease the cost of the shuttle per launch to about the same price as a standard non reusable rocket. They chose to stick with this design when the US station project became the international space station to allow each nation to build a part and to preserve the origonal design. The main purpose of this design (substantially increased space shuttle use) however was gone. It would have been more economical to launch the ISS in one or two pieces on a russian enirgia booster or two. Building the whole structure on the ground internationally is cheaper than assembling peices in space. At least according to Dr. Zubrin. It makes a good deal of sense. I suggest that you buy or take a look at Entering Space, it is very well done and informative. (Especially the first two thirds or so.)

Mark S · 2002-04-23 16:11:00

NASA had actually planned on an ISS that wold be launched as a single main piece aboard a shuttle derived rocket (with the station taking the place of the shuttle orbiter.) This was one of three configurations NASA looked at; it was probably rejected because it made too much sense. The final ISS design makes extensive use of Russian core modules originally designed for Mir-2. This decision was probably made to reduce the amount of R&D that America would have to spend on ISS.

RobS · 2002-04-23 17:41:02

I have comments on a few postings; I hope they are useful.

First, one does not need to build a lunar elevator to the point where something orbits the moon once every 29 days; one only needs to build it to the lagrange 1 point, which is the spot between the Earth and moon where the gravities of the two bodies cancel each other out. This point is something like 25,000 miles above the lunar surface. NASA is considering it as a possible point for a future station. Fuel from the moon could be delivered there, then dispatched downward to vehicles in various orbits above the earth. Vehicles heading to Mars could refuel there as well.

Second, if one has a space elevator, hauling mass to the top end is not such a serious problem. The cost of building the elevator is so enormous anyway, one could haul liquid oxygen and hydrogen up as easily as ion engine propellant.

One cannot send people from the Earth to the moon via ion engines unless they are in heavily shielded vehicles, because they spend lots of time in the Van Allen radiation belts on the way. If they have to be in heavily shielded vehicles, might as well transport them quickly in lighter vehicles instead using chemical propellant. The radiation belts start a thousand or two miles above the Earth's surface; the international space station flies below them and thus is not bothered by them. Geosynchronous orbit is in the radiation belt and thus human beings at that altitude require considerable protection.

Third: no one has mentioned tethers as a cheap way to send payloads to and from the moon. Rather than building 25,000 mile long cables, you need build cables that are just a few hundred miles long. You can design them so the cable touches down on the lunar surface at almost zero speed for a brief period of time. They can also "touch down" at about 50 or 60 miles of altitude above the Earth's surface and hook onto a payload transported there by a special aircraft. Tethers can also "fling" items from the Earth when that item rides the rotating tether to its apogee. Tethers can also catch payloads coming to the Earth from the moon or Mars. Exactly how the tether actually catches something seems to be one trick; you don't want to miss. But the tether has so much angular momentum--it needs to weigh five or six times as much as the payload it catches--it simply drops to a lower orbit when launching something or rises into a higher orbit when catching something come from space. It's a brilliant idea if it can be made to work because it conserves momentum. In Earth orbit a tether could adjust its orbit using electricity and the Earth's magnetic field; basically if it needs more altitude, it powers up its magnets and gets repelled into a higher orbit.

Tethers also have to have counterweights, and the counterweights can ride along the tether, moving to the top end, the bottom, or staying in the middle. Adjusting the counterweight's altitude adjusts the "tip speed" where you do the catching.

-- RobS

Shaun Barrett · 2002-04-29 22:11:33

Hi RobS !!
Just a couple of small points I'd like to throw into the discussion:
I note you mentioned that a lunar space elevator need only be built out to the "neutral point" between Earth and the Moon (Lagrange 1). I assume you mean that the centre of gravity of the elevator would reside at Lagrange 1; i.e. that the cable and/or some form of counterweight would extend beyond L1 towards Earth( ? ). I know, I know ... I'm nit-picking again! Still, it might be important as this discussion progresses.
Secondly, and I may be wrong about this, I seem to remember that if you draw an imaginary line from the centre of Earth to the centre of the Moon, then as the Moon revolves about Earth, that line does not always intersect the surface of the Moon at the same point. In other words, the Moon as seen from Earth, appears to shimmy from side to side; revealing first a little more of its surface to the west, and then a little more to the east. My point is simply to ask whether this 'shimmy' relative to Earth (and hence relative to L1), is likely to cause any destructive build up of resonance in the elevator cable; a kind of slow-motion whiplash effect?
And one more thing: I agree with you that from a conservation of momentum viewpoint, the rotating tether idea is about as elegant as they come! But I have strong reservations about its practicality because of the degree of accuracy involved. It would have to be like an exquisitely choreographed aerial ballet, with supremely precise measurements in all three spatial dimensions, and also in time.
I may be accused of being overly obsessive and pessimistic about all this, but I am genuinely interested in the details of this proposed lunar elevator. As an overview, though, since the Moon has no atmosphere, surely the electromagnetic railgun is the better solution at the lunar end, and an elevator at this end?
:0

Canth · 2002-05-02 14:26:01

A lunar elevator attached to the moons surface would have to be very long due to the extremely slow rotation of the moon. Interference form earths gravity in addition to the hugely greater cost of such a long cable probobly makes it infeasable. However there is talk of a cable which orbits the moon with the cable bottom close to its surface so that a veihicle could latch on to the bottom of it and climb up. This would move relativly quickly over the lunar surface but is more feasible than an ultra long cable. There is some pretty good discussion of the various ideas in entering space (for instance a carousel type arrangement). There is no reason a non attached elevator can't work, it would require heavy supervision and often need slight adjustments but would likely work quite well.

AndyM · 2002-05-03 00:48:45

As RobS points out, the lunar elevator would only have to extend to the L1 Lagrange point. So its length actually has nothing to do with the moon's rotation period, in the manner that the geostationary altitude has to do with the earth's rotation period.

Canth · 2002-05-03 13:33:18

It would have to extend a good deal furthur than the larange point because the centrifigal force exerted by the rotation of the cable needs to balance the total pull of the moons gravity on it. At the larange point a satilite would be gravitationally balanced however only a small part of the cable will actually be at the balance point the rest is sunk deeper and deeper in the moons gravity well. An attached cable thus needs to be very long, however an unattached cable in relative motion to the lunar surface could actually be quite a bit shorter reducing the amount of materials needed to build it. Also it has the benifit of allowing a circle around the moon access to the cable rather than just one settlement. The only reason a similar idea wouldn't work on earth or mars is that the cable would be moving faster than the atmosphere and friction with it would slow it down. A huge quantity of thrust of some type would be needed to hold the cable up, this kind of defies the whole purpose of the thing.

Mark S · 2002-05-03 15:44:37

Boeing, Lock-mart, and Northrop Grumman/Orbital Sciences have released fifteen images of what the next space transportation system may look like. The most intriguing concept comes from Northrop Grumman. A two stage, reusable rocket is carried by a flying wing from the runway to launcyh altitude. After its climb, the rocket fires its engines and the wing falls back to earth. I particularly like the idea because it eliminates the problem of ferrying the orbiter, and it has more flexibilty than a system that takes off from a fixed launch pad.

Canth · 2002-05-03 22:38:05

I agree that the air breathing engine as a first stage is great idea. There is actually no statement as to whether this configuration will take off horizontally or on a runway. The horizontal option improves preformance dramatically. Versitility of launch site is not so important at this point, and there will be plenty of options even for a horizontal take-off vehichle. This method and I beleive all the methods make the landing site very versitile, this is a bit more important as far as safety and flexibility than the launch site being flexible. It is said somewhere on the Space Launch Initiative homepage that designs for horizontal and verticle takeoff craft are in the works. I wouldn't rule out a craft that can be launched either horizontally or vertically interchangeably. This would allow for maximum versitility for small payloads and resque/crew delivery missions while allowing for the sheer lifting power needed for large payloads.

Peter Pevensie · 2002-05-04 02:39:46

...Because the Agency is a federal jobs program, it has no incentive to streamline operations.

Actually, with the hounds of Congressional #### trying to tear their budget apart, I'd say NASA has more than enough incentive to streamline operations. Perhaps this was President Bush's reasoning when he chose an OMB hatchetman for the job of NASA Administrator. ???

It has been suggested that shuttle operating costs would be decreased by a factor of ten if it was operated by a private company.

Correct me if I'm wrong, but didn't NASA hand over day-to-day operation of the Space Shuttle program (particularly maintaining the vehicles and turning them around from recovery to launch-ready) to a private consortium a few years ago?

I believe that a next-genaeration shuttle, designed for quick turnarounds, automatic health monitoring, and full reusability, would cut costs by another factor of ten. Only then will space tourism become a reality, and not a dream, for the masses.

This is the plan for the SLI vehicle mentioned above...but I don't think that "space tourists" are the intended market for it...

Mark S · 2002-05-08 09:07:02

I wanted to go back tn an argument I had made previously about fuel costs being a barrier to space access. I was reading "Case For Mars" the other day and Zubrin prettymuch shot my argument out of the water. In his example, using a methane-fueled SSTO to reach orbit, it would burn $14 of fuel for every pound placed in orbit. The key to an economical RLV, then, is simplified maintenance and a fast turnaround. Still, space access could be made even cheaper if we built an air-breathing aerospace plane.

Bill White · 2002-05-08 10:47:48

Here is a brief AFP quote from spacedaily.com

<< KOUROU, French Guiana (AFP) May 08, 2002
Arianespace satellite launchers are running into trouble with a reduced market for putting satellites into space and increased competition. >>

Also, I read that Indonesia wants to launch a single communications satellite and the major launcher companies are in a brutal fight for that one contract. There appears to be significant overcapacity in the commercial launcher business, which does not bode well for substantial R&D expenditures on new launcher systems.

Has anyone worked through a solution to the "demand" side of CATS - (cheap access to space)?

I have seen countless proposals for dramatic reductions in the cost of reaching LEO - however - Is there a clearly identified demand that would give a decent return on the investment needed to develop and deploy an economical LEO lift capability?

This strikes me as being a classic chicken/egg dilemma - we need CATS to enter space but there is not now sufficient demand to "cost justify" anyone spending the billions needed to deploy such a system.

Permanent human settlement of Mars and the need to supply that settlement would create demand for such lift capability but everyone says lower cost Earth to LEO is a pre-condition to starting such a settlement.

Any thoughts?

Canth · 2002-05-08 21:09:51

Catch-22

The key is a new market, like 1-2 hour garunteed delivery for packages etc. This could be done with a cheap vehicle made by an aerospace company which could invest the rest back into the program. This vehicle could make orbital flights into space and suborbital flights for packages. According to Zubrin there is a very large potential market for such a service which could jump start other industries in space through reduced launch cost.

Mark S · 2002-05-09 17:20:53

I definitely think that space tourism will drive CATS. Most people cannot afford to be a Dennis Tito or a Mark Shuttleworth, but the will to fly in space is certainly there among the public. The Cosmopolis rocketplane, currently being studied by Space Adventures, will hopefully give more people an affordable opportunity to experience space. If Space Adventures is successful, more companies will follow, and we will see CATS within our lifetime.

On a related note, a Los Angeles radio station is auctioning off a Russian shuttle, with a starting bid of $6 million. Assuming that the orbiter is spaceworthy, or if it could be made spaceworthy, could Russia restart production of Energia so the owner could use the shuttle as a space tourist vehicle?

Phobos · 2002-05-09 17:32:03

How on earth does a radio station get a space shuttle and make a profit starting the bids at six million? I bet the pilot's seat on the U.S. shuttles cost more than that by themselves. Yep, if this is for real, reality is definatley stranger than fiction.

Canth · 2002-05-10 22:07:05

I saw that on space dot com. Bizzare. If Russia really autherized the selling of a buran then they are even more desperate for money than they appeared to be before. $6 million, should be more like $50 million.

Phobos · 2002-05-11 12:27:49

I wonder if the Russians stripped the shuttles of all of their avionics, engines, and other high-tech components or if the shuttles are practically ready to be fueled up and launched provided someone could buy the external boosters. If they're still flight worthy and someone buys, I know a nice little place here in my home town where we could launch it.

Mark S · 2002-05-11 18:49:51

I'm thinking that the "Buran" being auctioned is a mockup or a static test article. The radio station has stated that this particular Buran is NOT the Buran which made the type's only spaceflight.

RobS · 2002-05-11 22:25:48

There's an interesting article on SpaceDaily.com that says the cost of tourism in low Earth orbit will go UP before it goes down because of supply and demand. The Russians can send only two tourists a year to the ISS; one on each Soyuz flight. But they already have three tourists lined up and fourth in the wings. They charged Shuttleworth 20 million after saying the second tourist would get a slightly cheaper rate (he didn't). Apparently the Russians give their space program only a quarter of the money it needs, so they have a high incentive to attract paying customers.

I think at the Aeronautical Encyclopedia website I read an excellent series of pages about the Burans. Each Buran has its own page. Only the one that flew into orbit is complete. There's a 90% complete one in Moscow, and the other two (I think) are even less complete.

--RobS

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Re: Future of Space Shuttles - How could the Space Shuttles be used?

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