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Next NASA Vehicles To Resemble Shuttles
ausoleil writes "Spaceref.com has an internal NASA memo outlining potential plans for the next generation of launch vehicles. They will closely resemble the current Shuttle and use some of the same hardware. Of course, they plan to leave the exploding parts out of their next versions. From the article: 'NASA has decided to build two new launch systems - both of which will draw upon existing Space Shuttle hardware. One vehicle will be a cargo-only heavy lifter, the other will be used to launch the Crew Exploration Vehicle.'"
To obscure that fact that we are going back to a model used back during Apollo. After all this waste, we go back to non reusable heavy lifting and deorbiting like a stone.
Erm, actually they are keeping the "exploding bits" and leaving out the bits that so far haven't exploded. The SDV will include the solid rockets (which doomed Challenger) and the fuel tank (which doomed Columbia). The only bit they are leaving out is the orbiter, which has so far has worked properly.
Having said that, it is still an extremely good design. It's almost exactly what the Soviet Union built (separate Energia heavy lift and Soyuz crew vehicles). The only difference is the use of solid motors (which explains why the stock price of Thiokol's parent company has been going up like a, erm, rocket).
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The solid boosters ignition starts with a small Nasa Standard Initiator (NSI) http://www.hstc.com/pdf/nsi.pdf.
That then ignites a small pellet of boron / potassium nitrate.
Which ignites a small rocket motor which is about 4 inches long.
Which ignites a medium sized rocket motor about three feet long.
Which fires a jet of flame for about a tenth of a second, all the way down the whole inside length of the solid boosters, which ignites the whole inside at the same time.
Well, I've been trying to submit a story to slashdot over the past few days about a "parallel path" to government-built shuttle-derived that NASA recently announced, but I haven't had any luck. I've already had four or five variations on it rejected. Anybody have ideas on what might be wrong with the following submission?
At a recent talk, Michael Griffin outlined NASA's plans for helping to generate a robust and competitive commercial market in orbital spaceflight. The speech and Q&A transcripts from the talk are available. In a move reminiscent of the US government kickstarting the early airline industry by purchasing airmail services, NASA plans on supplementing government-derived transport by purchasing cargo delivery services to the International Space Station from commercial providers, followed by crew transportation after the systems have proven themselves. Unlike traditional government contracts, sellers wouldn't see a profit before the services are delivered and the emphasis will be on actual performance instead of process and specifications. Aviation Week has some commentary on the announcement.
The vehicles being proposed do not at all resemble the shuttle. The shuttle itself is being scrapped. The solid rocket boosters, a modified external tank, and the Space Shuttle Main Engines (SSME's)
The key difference between the new models and the existing shuttle is serial architecture versus parallel architecture. The Space Shuttle is an example of parallel architecture - all of the stages firing together. The new proposals operate in serial, one stage at a time. That's a lot safer: abort modes are easier to implement. A first stage failure is not immediately a fatal incident. Also notice they are implementing the CEV for the crew module, not a shuttle.
And although the spaceref article and pretty pictures are new, the ideas/rumors have been floating around the Aerospace community for quite some time now.
-everphilski-
It would be great to be able to put up 100-to-1000 kg payloads in LEO, inexpensively, reliably, frequently. The space science community would be overjoyed, but they would not use the ability to assemble big things from little things.
Suppose that the way you got a new automobile was by having it mailed to you in 50 pound packages. It is probably possible to get cars this way, but the cars would be very different from the cars we have now --- heavier, slower, less fuel efficient, leaving a rather larger trail of (packaging) debris, and a few specialized tools, that would be useful for nothing else. Such cars would probably have no welds for assembly, and manufacturing techniques which required hazardous chemicals or heat processing would simply not be available. The lesser performance would arise from the "design for assembly" which is rather different from "design for manufacturability." (If the 50 pound limit was enforced, there would be no monolithic engine blocks; this would probably imply the existence of many small engines coupled together with a complex, heavier, transmission.)
The upshot here is that, from the point of view of weight, energy efficiency, complexity reduction, maintainability, testability, there is practically no sense in which it would be advantageous to create a big thing by launching little things for remote assembly, unless it becomes far cheaper (cost per kilogram) to launch little things than big things.
You're leaving out the fact that a portion of the engine is built into the orbiter. I'm not sure exactly what it masses, but I'd take a guess it's bigger than the difference between 118,000 kg and 132,800 kg.
On a totally unrelated note, why don't we use the rest of the metric scale when dealing with really big stuff?
Have you been touched by his noodly appendage?
I'm not old enough to have remembered anything about anything to do with space launches and exploration, beyond historical events (landing on the moon almost a decade before I was born or updates about space probes that were sent out before I was born).
The only "big" space events and launches in my life time were the Columbia, which exploded, when I was seven years old, the next successful launch to occur after that disaster (not a big deal, other than everyone in the world tuned in to see if they made it through the launch) and then the explosion upon re-entry a couple years ago.
So really, my generation knows little more of the space program outside of historical events, save for disasters and budget crunches.
People are so narrow-minded and short-sighted that they think "we should be spending money on helping our own people here on earth instead of exploring space". Well, look, there will always be misery and poverty and hunger and war on earth. We're not going to change that and we can't sacrifice exploration and the future of the human race (and ever creature on the planet for that matter) for some fantasy date way off in the future when the world will be perfect and we can proceed with uncharted territory.
Personally, I want us to be a major player in space. We should have stations and colonies already. We should be looking toward a future when mankind has several planets and when his existence as an entire species isn't hinging on the potential devestation of any number of cosmic events that could occur on his home world.
Space exploration is inherently about the continuation of the human race. There is nothing more natural, human or - even - American than that. And damn it, I want to have the awe and thrill of watching heros do amazing things and take amazing risks to explore the universe. My generation needs their own Right Stuff. We need our own glued-to-the-television-in-anticipation experience.
I mean, does anyone even think that landing on the moon a second time is going to be much of a news story? I doubt there will be much coverage (and certainly not real-time) of the launch. And even when they make it to the moon, it will probably rank as a quick blurb in between sports scores and weather on the news. Nothing more. There won't be parades. There won't be speeches. There wont' be much of anything. And I sympathize with the astronauts who probably themselves dream of conguering new territory rather than re-hasing what others have already done.
Ok, so I'm probably not the only one here who's dissapointed in finding that NASAs next big plan looks and sounds really BORING. But if we're really serious about space exploration, then what's most important is what it can do to further that progress, not how it does it. Now, my big gripe is that "progress" itself doesn't seem all that important in this design as Congress keeps whining about space program employment and timeline crunches, but if this is the quickest and cheapest way to improve the space program, I'm all for it. It'll be the plan that probably gets humans to mars, after all... probably late in it's lifetime (probably no sooner than 2025, I forget the timeline).
But strangely enough, it looks like R&D for new space technologies is on the backburner at NASA to fund the actual program, while new private enterprises such as SpaceShipOne and LiftPort research and develop contemporary technologies that can achieve things like reusable, horizontal takeoff space planes and the space elevators. Problem is, the last 30 years have seemed to be fairly unproductive in terms of designing new space transportation oriented technologies. There have been numerous "space plane" projects, yet none of them have been able to produce a viable plan that is both doable and cost-effective. So, it's no wonder that NASAs cheepest solution is to basically make a new plan that simply reuses older technologies. That said, with the new companies mentioned, as well as many more in their early stages, this next generation of space transportation will see a much higher amount of R&D. Come 2040 (or whenever the new space shuttle fleet retires), there will be much more new space transportation technologies for NASA to steel. Until then, it looks like sexy spacecraft are more destined for private enterprise.
BTW: reading up on the concept of a "Space Elevator", the implications of such an installation are immense. I'm picturing a private enterprise like LiftPort completing one by 2020. Suddenly NASA turns around and realizes that they can completely skip earth to orbit spacecraft and scrap their current fleet to create space-specific craft which are more fuel efficiant than airplanes. Whoops! Leave the bottle rockets to kids.
Multiplayer Gaming (defined): Sitting around, discussing single-player games with my friends, at the bar.
... all of our old mistakes.
Horrible, horrible idea. They're taking two of the three worst components of the current shuttle platform and reusing them in a system where we have already made and used much better systems. The only way they could make it worse is to rely on the current shuttle thermal tiling.
So, lets look at the other two pieces. SRBs? They killed Challenger. They've never worked properly, or we wouldn't have been getting blow-by as routine. If NASA is insisting on sticking with solid fuels, for whatever odd reason, they need to make them non-segmented (although there are other practical problems here that would have to be solved). Increasing the segments to five is just going to make the problem much worse, since the joints are the weakest part of the system, which means more losses.
Then we've got the SSMEs. Good ISP, fine, but the mechanical problems are still around. We've never, ever been able to get these to work the way we wanted them to. NASA just keeps moving the "acceptable" bar every time a new problem is found. They need a complete redesign to get rid of the problems we do know about (that's what top-down design gets you), but that'd be far too expensive. If we want to stick with old tech, we'd be much better off just remaking the tools for the Saturn V engines and restarting production.
If this memo at all reflects NASAs future actions, then they'll have proven themselves irrelevant. Unles the US government decides to try out a bounty system, and offers appropriate (ie. billions) numbers for good systems, we're out of the race. Maybe someone else will be able to keep going.
Alita
"Cutting the space budget really restores my faith in humanity. It eliminates dreams, goals, and ideals and lets us get straight to the business of hate, debauchery, and self-annihilation."
-- Johnny Hart
The original shuttle design was going to have the shuttle itself only used for lighter payloads, with the HLLV doing the, well, heavy lifting. There was also going to be a permanently orbiting vessel for inter-orbit transfers, using something like an ion drive... basically, the original shuttle design was going to be lighter and more reliable and just one member of a fleet of specialised vehicles. Congress wouldn't pay for all of them so NASA scaled up the Orbiter and it ended p costing more and doing less than originally planned.
Man, I hope they let NASA do it right this time. If they reduce the weight of the new shuttle so the SSME don't need to run over redline just to do their jobs, maybe they won't have to rebuild it after every flight like it was some damn MIG engine... and if the HLLV doesn't need to be man-rated they can use a less expensive version of the SSME in it and save even more.
Over 100 of those was due to a single incident in 1960 which was actually an ICBM test, not a general-purpose space mission. Under extreme pressure from the top government ranks to keep the cold war test on schedule, safety regulations were ignored while frantic launch preparations were made on a fully fueled missile. Somebody accidentally made an electrical connection that ignited the second stage, which engulfed the ground crew in fire.
That singular incident really doesn't have much to do with the current statistical safety of manned space flight.
I haven't checked this out, but a Usenet poster said the original Shuttle frames were going to be built out of titanium, of course for its great strength-to-weight ratio. There was a decision to switch to aluminum, supposedly both as a cost savings on the Shuttle manufacturing, and because there was great demand for titanium in building US Military aircraft. Due to the extra weight of a same-strength frame made of aluminum, two solid-rocket boosters needed to be added to the launch vehicle which were not a part of the titanium design.
Is this true?
Regardless, it seems clear that any launch hardware intended for reuse should be made of the best strength-to-weight materials available even at larger initial cost, so either there's less energy (the fuel itself is rather cheap, but less of it means smaller launch vehicles, fewer complications, fewer SRB's, etc.) required to launch, or a larger payload could be put into orbit with the same launch energy because of the lighter hardware.
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