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Here is my plan:
First, we keep the Shuttle running until its replacement is designed. After this we build 5 spaceplanes a year, and every 5 years, we update our production lines to a new model.
This way, we never have to make revolutionary and costly retooling changes to our production line, but we keep a modernized fleet.
As ships turn 15, we phase them out, as they are constantly replaced by newer, more modern ships. We dont face another problem like the Columbia. The new, cheaper designs actually save us money by making production cheaper, and keeping research current.
This allows a large, cheap fleet with state of the art technology. As Congress and the public see a successful space program, funding will increase in hopes for more. More R&D could be done, and the process could be a self-perpetuating sequence of events.
Questions, comments?
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Since you don't know how much the orbital space planes will cost each, and how much it costs to refurbish them, how do you know this will be "cheaper"? The shuttles are no longer being made because of the high unit cost.
-- RobS
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The next design will almost certainly be cheaper. For one thing, the OSP's are smaller, and from what i've seen, lifted by a single booster. they arent as complex, either. i doubt we'd make something MORE expensive as our next step. Do you really think Congress would approve it?
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NASA plans to keep the Shuttle running until the Space Planes are finished (and until the ISS is complete, I think). Since they're so small, and simple, I don't see why we couldn't have a fleet of them.
But I don't see why we need to phase them out. Just make them modular. Make them easy to retrofit. They all serve the same purpose, really. Gliding back down and landing. The areodynamics for all of them will be identical.
A fleet of Space Planes is good, but almost pointless I think, considering that all we have is the ISS... where would they be flying to? Going up and doing experiments? They couldn't do the same ammount of experiments as the Space Shuttles, could they? They have much less capacity... but perhaps they can. If so, understood. Go for it.
Some useful links while MER are active. [url=http://marsrovers.jpl.nasa.gov/home/index.html]Offical site[/url] [url=http://www.nasa.gov/multimedia/nasatv/MM_NTV_Web.html]NASA TV[/url] [url=http://www.jpl.nasa.gov/mer2004/]JPL MER2004[/url] [url=http://www.spaceflightnow.com/mars/mera/statustextonly.html]Text feed[/url]
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The amount of solar radiation reaching the surface of the earth totals some 3.9 million exajoules a year.
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USA Today has on it's weekend edition (7-9 Feb03) cover, orbital space plane on it's front page. The article also mentions that NASA needs a more broader Apollo-like mission.
One day...we will get to Mars and the rest of the galaxy!! Hopefully it will be by Nuclear power!!!
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I think that even a spaceplane like OSP will be too expensive to replace every five years, and it will take more than five years for a replacement to come along. I think a ten-year cycle is more reasonable.
The problem I see with OSP is that NASA will own and operate the system. I don't believe that a manned spacecraft can meet the safety and cost goals unless it serves double-duty as an unmanned cargo rocket. Such rockets would be chartered by NASA rather than owned by NASA. Eventually, OSP will (hopefully) be mated with a reusable booster. The spaceplane will be NASA's contribution to the entire system, but the boosters should be privately-owned and the OSP privatized at the earliest possible date.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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My main point was keeping modern. And another point was not revolutionary upgrades like shuttle to OSP, but gradual upgrades, like wing changes, or different boosters-so you keep a similar production line, with minimal retooling costs. It would be relatively cheap to impart these new changes, because you are keeping the same basic design.
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Another possible destination for an orbital space plane that I could see would be flights to a space station at the L1 Lagrange point (between the Earth and moon) or even to high lunar orbit. This would be accomplished by launching a chemical booster into orbit, then the OSP, which would dock to the booster and be propelled to L1. The delta-vee is something like 3.5 km/sec, which means a 24-tonne stage could push a 16-tonne OSP. The OSP would require heavier thermal protection for the return ride, as it would hit the atmosphere at 25,000 mph rather than 17,500 mph. It would also need a longer lasting life support system; a week, rather than two or three days.
At the Lagrange point, the OSP would dock with a lunar-based vehicle and the crew would transfer to the latter for a ride to the lunar surface. The LBV would be fueled using lunar hydrogen and oxygen. Or the OSP could dock to a Mars mission which had fueled up with lunar hydrogen and oxygen for the trans-Mars injection burn.
The OSP would be complemented by an unmanned cargo vehicle lifting cargo to low Earth orbit and a solar-ion tug that would lift cargo to L1. The OSP thus becomes an important element in a space transportation system.
-- RobS
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I lke this talk of crew taxis, but I think that it makes more sense to use capsules instead of space planes for moving humans between LEO and either Lagrange Points or the moon. When NASA released its Mars DRM 3.0, it included a study of the tradeoffs between a capsule and an X-38 crew taxi for ferrying humans to a Mars spacecraft in HEO. The result was a weight savings around 10,000 kg for the capsule. Studies like this make me wish we'd have kept the Apollo capsule in production for use as a rescue ship or Earth Return Vehicle for future missions.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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Some intitial problems with this concept:
1) Choice of method of reusable launch vehicle would lock in all future developments.
If we decide on a glider attached to a rocket, than all future versions of the OSP would be based on glider/rocket launch improvements. Continued reliance on this production system would further inhibit revolutionary designs, or kill technology developments that are nopt related to the intitial launch method.
You end up with ONE space launch infrastrutre that would work to maintain the staus quo- new technology that could change how we get to space would not be favored unless it works within the production system.
2) The OSP is designed to get people into space, nothing else.
What use is a growing fleet of OSP? You need orbital platforms to do the science- the OSP is nothing more than a taxi. Why build a fleet, and continue to build more if all we need is 5 to get the people into space? If the OSP concept works, then perhaps private enterprise can build them for private tourism ventures- but what reason does NASA need to build them?
A fleet production system is only needed if we need to commute a large and growing number of people into space to do something- but right now, there is nothing to do, and very few places that the OSP good go to begin with.
I believe this is a matter of the cart before the horse.
And as for OSP beyond LEO... well, the OSP is meant for LEO and return. The requirements for beyond LEO should be handled by a seperate system, preferably one that is already in space- use OSP for taxi to and from space, and develop a seperate system for LEo to L1 or Luna.
Learn from the Shuttle, one size does not fit all.
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well, thats my point, since you have an existing assembly line, you can modify the size or customize the vehicle with little difficulty. Since you could redesign every few years, you could use new concepts, and you have 3 different concepts at any one time (since you phase out every 15 years with a new design every 5).
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Since you could redesign every few years, you could use new concepts, and you have 3 different concepts at any one time (since you phase out every 15 years with a new design every 5).
And that's my point, you lock yourself into ONE system.
Sure, you can redesign every dozen years, but all you are redesigning is the chasias of the basic concept.
This would effectively kill such concepts as Light Craft, or other revolutionary methods to get into space.
You will be redesiging the concept of Glider on Rocket to space forever.
All you will do is improve the Glider, improve the rocket- but it dosen't meant he best means of getting into space is being pursured. All you ae doing is making incremental improvements into one method to get into space.
It limits overall options.
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I never said you have to limit yourself to one system. You could build 15 a year if you made it cost-effective enough, 3 each of 5 different launch vehicles. My main focus, once again, was keeping modern.
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I never said you have to limit yourself to one system.
No, but what I am pointing out is that we WOULD be limited to one system with this approach. Sure, we could have 5 different versions, but then again, Mars could mean something to the average citizen- fat chance on either being realized.
NASA should be developing technology, not actual systems. The Space Shuttle is what happens when NASA develops systems- a huge buecracy and production infrastruture develops and locks us into place- that's what happened with the shuttle, and why NASA drags it's feet moving beyond anything other than glider on a rocket concept.
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I agree-NASA or a similar agency should be resposible for giving out permits to organizations seeking space launch, and R&D.
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Because OSP is designed only to launch crew and limited amounts of supplies, it is insufficient for the purpose of replacing the Shuttle. For near-term missions to bring supplies to the station (shuttle logistics module or Progress resupply,) NASA should consider pumping money into the Kistler K-1. The system is nearly complete and promises to make spaceflight cheaper than it is today for comparable sized payloads.
In the far term, NASA and the contractors should be thinking about a heavy-lift cargo RLV. The vehicle would be developed by the industry to tap into a commercial launch market that will have hopefully recovered by then. This vehicle would have a payload in the same range as the current shuttle and Delta IV/Titan IV/Ariane 5 series rockets. This RLV can be used for the assembly of future space stations or the assembly and servicing of reusble Mars shuttles.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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Well, like I said, an NTR could be the ultimate HLV RLV with current tech. to get about 100 tons to orbit, youd need a 400 ton launch mass. you could scale it up as necessary, and plan for longer missions, because you could take your fuel into orbit with the increased cargo capacity.
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Soph, you've started something. But, in all of the above responses, there doesn't seem to be a reuseable scheme suggested so far, to boost the proposed spacecraft out of the atmosphere!
I glanced at my World Atlas just now at Peru, at the foot of the Andes. They appear to go abruptly up from the desert along the Pacific coast, to five and six thousand metres. I would love to start some discussion as to the practicality of building a maglev booster-sled track up the slopes of that mountain chain.
The spacecraft would ride a retrievable sled to the top, separating from it at Mach 0.9 (say) at some steep angle of ascent, to further accelerate out of the atmosphere by whatever propulsion means the client space agency has adopted for their particular spacecraft.
Upon separation, the sled would continue in a trajectory out over the Atlantic Ocean, using airbrakes, and then by deploying a Ragallo-type flexible wing to perform a remotly piloted soft flying letdown to a designated retrieval location in the ocean. The sled would then be returned by ship, via the Panama Canal, to the lanch facility.
The launch facility (nationally and/or internationally owned and operated) would be expanded rather than rebuilt, by adding parallel tracks up the slopes of the Andes, to handle increasingly heavy spacecraft as future needs develop.
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dicktice-the NTR could use built in boosters, which could land along with the NTR, which could be HTOL, because of its more favorable mass ratio. You could bolt the tanks to the shuttle, again, because you can carry more payload, and keep fuel in orbit. Everything except the fuel rods, which could absorb any waste could be reusable.
I'm not sure if you could then recycle the fuel rods by breeding-Robert?
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You might be able to have a fast reactor inside the NTR to breed fuel, but a more feasible idea might be pyroprocessing the spent fuel from the reactor at a separate facility.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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The usual process of breeding is to expose uranium U238 to neutron radiation to produce plutonium Pu239. Fissile uranium is U235, so the lowest mass nuclear fuel will be highly enriched uranium that has little U238. The by-products of fission of U235 are not useful as fuel, and they are the dangerously radioactive part. Most of the radioactive waste can be processed into non-radioactive forms by exposing it to controlled radiation from another reactor. This is best done in a reprocessing facility.
You could design a SSTO RLV to be similar in size and shape to the X33, but NTR engines would give it a lift capacity similar to the current shuttle. X33 was the scale model of Venture Star, so X33 is much smaller than the Shuttle. This wouldn't require a sled, or any other gigantic ground facilities. It could use the same integrated landing runway and launch gantry designed for X33.
The non-nuclear option for SSTO would be a SCRAM jet, or more to the point a Rocket Based Combined Cycle (RBCC) engine. I still think a turbo jet or fan jet would be best for take off and landing, rather than a launch catapult and glider landing. The extra engine is dead weight, but permits launch from a runway and powered landing. X-43A has shown that progress on SCRAM jet technology is slow. Until someone commits themselves to a development program, SCRAM jet based launch vehicles will be a long way off.
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Right, so you could get around 25% of the launch mass to orbit, according to my estimations and calculations. This gives it an 18x efficiency edge over the Shuttle, and opens up some amazing RLV and HLV possibilities.
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Until someone commits themselves to a development program, SCRAM jet based launch vehicles will be a long way off.
On the Discovery Channel, I heard that some dudes (and chicks) in Australia are working on a SCRAM jet engine. I think it was for use in the atmosphere though, not as an engine to launch with.
[url]http://kevan.org/brain.cgi?Echus[/url]
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Scramjet is unreliable, as is ramjet, ramjet to a lesser extent. It would take a lot to refine it to a scramjet to the point where its reliable enough for use on aircraft or spacecraft.
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I heard that some dudes (and chicks) in Australia are working on a SCRAM jet engine. I think it was for use in the atmosphere though, not as an engine to launch with.
That's the drawback to scramjets. They're totally useless outside the atmosphere. For this reason, Pratt & Whitney, Boeing, NASA, the Air Force, and everybody else in this field is focusing on Rocket-Based Combined Cycles and Turbine-Based Combined Cycles for operational aircraft and spacecraft.
For a brief but entertaining primer on combined cycle engines and hypersonic flight, I highly recommend Bill Sweetman's "Aurora: The Pentagon's Secret Hypersonic Spyplane."
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
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