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NASA's Shuttle Plans
Gerhardius noted a NYT article (you know the obnoxious deal) about new "shuttle" designs coming out of NASA. The payloads are riding up top to avoid debris.
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As long as we're no longer trying to send up cargo along with personnel, now might be a good time to revisit single-stage-to-orbit designs such as the Delta Clipper and the Roton.
I don't recall any debris problems with either of these designs, although the leg design seriously needs to be rethought. If you have four legs, a failure of any leg results in disaster (witness the spectacular failure of the Delta Clipper). Six legs, on the other hand, would be far more stable...you could lose any three (provided they're not all adjacent) and still pull off a successful landing.
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~ |rip/\/\aster /\/\onkey
What they are effectively saying is, the 30 year experiment that was the space shuttle was a failure. Sure, a lot was learned - but now they are going back to the basic design concepts (upgraded with new tech, of course) of the 1960s. Live and learn.
NASA claims that the tile gap filler that has come loose was a result of vibrations on liftoff, NOT the result of falling debris...
So moving the return capsule up to the nose of the craft will prevent repeats of 1986 and 2003, but won't fix every problem. They should instead be trying to build a shuttle that won't rattle apart on takeoff.
Single-Stage to orbit isnt feasible (yet). We need either a breakthrough in materials technology or propulsion performance. The rocket equation is
... as a single stage ... but your not coming home. Reinforcing the ET takes such a mass penalty your payload is effectively reduced to zero.
Delta-V = g * Isp * ln( MR )
where:
Delta-V: velocity required to achieve LEO (7.6 km/s best case scenario: but you need to add gravity and drag losses, add at least 1 km/s)
g: gravity (9.8 m/s)
Isp: Specific impulse of your propellant. This is an efficiency factor: 1 kg of propellant generates Isp kg of thrust. Hydrogen and Oxygen properly mixed generates an Isp of about 450 [seconds] in a vacuum. That is the upper level of chemical propulsion.
MR: Mass ratio. Mass that sits on the launchpad divided by the mass that achieves orbit.
Play around with that equation and you will see STS0 just doesn't work out yet. Our feasible Isp is way too low and our current material properties won't let us build a ship with a MR of over 10 that can return to earth safely.
Interesting factoid though, if you attached the space shuttle main engines to the external tank and just made that a launch vehicle, as a single stage it could put damn near 100 tons into LEO
-everphilski- -- Rocket Scientist
Is the whole design of the shuttle overly fragile?
I understand that there are some sizable forces acting on the launch vehicle, but how can insulating foam do so much damage?
And, if insulating foam can damage the tiles, what about micro meteors or drifting debris from previous flights?
Isn't there a way to put a shrouding over the tiles that would be jettisoned with the fuel tank? Protect the tiles until the shuttle is free of the fuel tank and solid rocket motors.
I can't believe that people are still denying the truth. Just yesterday, there was a SECOND article about the discover of Planet X. Planet X is returning on it's 4000 year orbit, which means that the race that enslaved us nearly 4000 years ago, the Niburu are coming back. It's not a surprise that we haven't had a successful manned space mission in the last few years. The Bush administration, NASA, the U.S. military and some of the most powerful corporations on the planet are covering this up. Why, you may ask? Because, they have a deal with the Niburu to spare their families from the enslavement when they arrive in a few years time. It is as it was written by the Sumerians and as Zecharaiah Sitchin translated (he is the only man on Earth who can read ancient Sumerian properly).
One of the requirements that the Niburu required as part of the deal is that humans will not make any manned flights off of the planet anymore. This is why we haven't been able to get a shuttle off the ground for so long. NASA talks about the supposed failures of various systems, but it's just a cover-up. Just like the cover-up they pulled off when the manned space station jsut a couple years ago hear strange sounds coming from the outside. The sounds were the sounds of a Niburu operative crawling around on the outside of the station. NASA later claimed it was just a bit of casing that had been damaged and needed to be fixed. What really happened? The anstronauts were reprogrammed to become Niburu operatives and came back to Earth to infiltrate NASA.
What about the dead astronaut found in the Arabian dessert? What? You didn't hear about that? Maybe it's because the Niburu controlled media don't want you to hear about it. They've been stirring things up on the global front to get the commoners at each other's throats so that we are in disarray when they arrive to enslave us. The real story is that a dead astronaut was found in the Arabian dessert after he had unwittingly announced the discovery of Planet X back in the 90s when that comet was going to slam into Jupiter. Why didn't Jupiter ignite into a big sun when that happened? Because the Niburu prevented the ignition with their awesome mind control. But they didn't do it to protect us out of goodness. They did it to protect us as property. So, this dead astronaut was found in the Arabian dessert. And that's why.
Don't fall for the cover-ups. Read the teachings of Zecharaiah Sitchin. And prepare for the intergalactic battle with the Niburu. Our politicians, military and business men have sold us out, so it's up to us to get armed to the teeth and fight when the invasion force comes. One of the most imporatant weapons you can get right now is a telescope and some astrophotography gear. Print out the photos of the impending approach of Planet X and post them everywhere online and in real life. Make sure that everyone knows about the conspiracy. This ain't no time to go wastin' away in Margaritaville.
-"...bad old ideas look confusingly fresh when they are packaged as technology" - Jaron Lanier (Digital Maoism on Edge.o
I know they're falling back to the Apollo-style basics here, but this is still, in some ways, compromising efficiency and performance in light of crew safety, which is important. However:
"A ship in a harbor is safe. But this is not what ships are built for."
I would be fine with the new design concepts if we use a Crew Return Vehicle design. One, it can carry more people and a small amount of cargo. Two, it can also be placed atop like an Apollo-style capsule. Three, it is more reusable. Think of it as a mini-Orbiter.
Reusing and readapting the ET/SRB devices is a frugal idea as well. We just need something to routine get up and back to the ISS. Perhaps we should also look into making an in-orbit shuttle that stays in space and can move between LEO, the ISS, and the moon.
Vos teneo officium eram periculosus ut vos recipero is.
Your ideas are intriguing to me and I wish to subscribe to your newsletter.
The owls are not what they seem
It was originally an Air Force project. When video of the first test was shown at ConFrancisco in 1993, it was said that if it ever got transferred to NASA they'd kill it.
NASA was threatened by the Delta Clipper. A ground crew of 3 instead of 15,000? We can't have that! A NASA employee failed to connect the landing gear hydraulic line for one of the tests shortly after NASA took over the project.
These days NASA is more of a jobs program than a space program.
Might you be willing to share some of the "groovy pharmaceuticals" you are partaking in? If your writings are any indicator, they seem to be of exceptional quality and potency.
"So after all this, you make my case for me. To end this stalemate, you must die..."
Don't trust anyone under thirty.
The only reason the foam is there is to keep ice from forming on the side of the tank. Since the fuel is cryogenic, it is obviously quite cold and causes large chunks of ice to form on the side of the tank. On launch this ice would simply destroy the Shuttle's tile system, it would be much much worse than the foam. If there is nothing for the ice to damage, then you don't really need the foam anyway. Many rockets have no such foam at all. Ice just builds up on the rocket and sheds during launch. You can see this in a lot of launch footage from the gemeni/apollo days. The ice would fall to the pad as the launch clears the tower. The absence of foam is not likely a significant safety risk, but it is probably still usefull enough to keep. I'm sure it has several side benefits, such as allowing the tank to stay fueled and on the pad for longer periods of time.
Goes to what I've been thinking for years. Separate the cargo from the humans. They have vastly different and sometimes conflicting needs and the launch vehicle design to support both is much too complex. Use Big Dumb Rockets (BDRs) to lift cargo (heavy), smarter, safer ones to lift humans (light).
The idea of a runway landing orbital vehicle is nice and, IMHO a great goal. But it turns out to be harder than originally thought. The vertical, rocket assisted capsule design seems to be good compromise for the short term (5 to 10 years).
In the medium term (say 10 - 15 years), advances by companies like Scaled Composites (http://www.scaled.com/) show that runway-to-orbit-to-runway is possible, but needs more work. Eventually that's how we'll get to orbit; using small, "space planes" to take humans to meet with low earth orbiting platforms that were launched with BDRs. We're good at putting together stuff in orbit and we're good at rendezvous and docking.
None of this is new. It's based on concepts from the Apollo days. Remember Earth-orbit-rendezvous? Heck, the Russians have never left the basic capsule design.
Keep It Simple (Stupid) is especially important for manned space flight. It'll never be safe, and the American public has to accept that there is risk, but the less complicated it is the less chance of something going wrong. And the cheaper it will be
It's OK, NASA figured out how to rendezvous in space with two nearly simultaneously launched vehicles in a little program called Gemini.
I think they were successful, might have to check Wikipedia though
Four weeks, Twenty papers, that's two dollars
I think that because of Star Trek, we are all beholden to the idea of anti-matter propulsion. That may come to pass in some distant future, but right now, it is a fairly unrealistic blue-sky idea.
I would put my chips on nuclear fusion as the long-term future, whenever we develop a replacement for chemical rockets. May years ago, Space.com cited some NASA experiments in the field:
NASA engineers are developing a radically new type or rocket engine that harnesses the power of stars to cut travel time to Mars, for example, from the current nine months down to three months. Called the gas-dynamic mirror engine, it traps and heats gas to temperatures as sizzling hot as those found at the core of the sun. That's hot enough to allow for nuclear fusion by combining lighter atomic nuclei into heavier nuclei.
Within a few months, a six-foot long model of the engine will be fired-up by injecting a superheated gas confined between powerful magnets at either end of the engine. Within a couple of years, the engineers hope to achieve a sustained nuclear fusion reaction in the hot plasma.
The article also mentions a fusion/anti-matter hybrid, but the former sounds like it holds more promise in the 30-50 year time frame...and who knows what future developments may hold?
In the near-term, solid rocket boosters put a lot of energy into the nozzle, so to speak. The current Shuttle gets roughly 80% of it's ascent propulsion from the solid rockets that are strapped aside the fuel tanks. That's a pretty powerful combination. The problems with solids are legendary, most notably the lack of any capability of trimming, reducing power or turning them off. The Shuttle is the only launch system that's man-rated that uses solids in a significant way, but this technology is tried and true, considering it is a veteran of many a shuttle launch. While the Challenger failure was a result of the SSRB's, it was a materials issue and not a flaw in the basic package.
Yes, the Shuttle is a complex machine. I've heard that over and over again each time I see a shuttle launch program on TV, or when astronauts talk about it.
That is precisely the problem... not the ice damage or the configuration. Any engineer from any discipline can tell you that each time you add a new part or increase the complexity of a machine that you are likely to screw it up.
At their heart, a rocket is a very simple machine. You throw "stuff" out the back end of the rocket, and as fast as you possibly can. The trick that modern rocket builders need to deal with is that to achieve orbital velocities you need to have a rocket that sends "stuff" out so quickly that it reaches insane temperatures, and even incredible temperature differences (going from -200C to 4000C in less than 10 seconds for the fuel). You also need to have a "fuel pump" that can effectively pour a controlled but huge volume of fuel at constant (or at least consistant) pressure. Indeed, it is the design of an efficient turbo pump to push fuel into the combustion chamber that most rocket scientists spend their time. And where most of the complexity comes in. Dealing with cryogenic fuels also has some additional problems (in the case of the shuttle).
The trick to reduce errors and failures is that you have to simplify the idea and approach. One solution to this issue is that if you have an assembly line of rockets being built, you have other incentives to simplify... mainly because it gets cheaper to build them in the first place when there are fewer complex parts.
The current fleet of Space Shuttles are each hand-crafted and in many ways unique craft each in their own right. They each have a very interesting history, and in some areas you can't "mix" and "match" or change parts (although sometimes NASA tries real hard in this prespect).
As you also pointed out, there were problems with the tile system. When it was first proposed, even before STS-1 with Columbia, there were quite a few complaints about this heat-protection system. There was at the time a "wait and see" standard mantra coming from NASA, to see just how effective it was. And indeed it has been quite successful in a number of ways, but it has proven to be far too fragile for repeated flights.
The other thing that a redesigned Shuttle would have in its favor is that it wouldn't have the U.S. Air Force RFP requirements, many of which caused huge problems and setbacks for the Shuttle program even before it got going.