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Boeing: Space shuttles to last into next decade
In article , Larry Dighera
writes: While the cost to operate the shuttles may be great, imagine the cost, in today's dollars, to build a replacement and train the personnel. Compared to the cost of operating existing shuttles, it would be many times greater. Blame it on NASA. If there is a lack of alternative "heavy lift" capability, it's only because over 20 years ago, NASA mandated that all future government payloads be designed around the shuttle, and all alternatives to the shuttle be scuttled. This was in order to make the shuttle a "necessity" to America's space program. The reality was that the economics of the shuttle were complete fantasy, and NASA knew it. (hence the mandates leaving the US with few alternatives until the French, Russians, and Chinese started filling the void) We could (and perhaps should have) gone on building disposable Saturn-like boosters (500k pound payloads, vs the shuttle's 30k to 40k). The R&D was paid for, and the support costs would be a fraction. (A typical shuttle mission costs somewhere around half-a-billion) John |
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"JohnMcGrew" wrote in message ... Blame it on NASA. If there is a lack of alternative "heavy lift" capability, it's only because over 20 years ago, NASA mandated that all future government payloads be designed around the shuttle, and all alternatives to the shuttle be scuttled. This was in order to make the shuttle a "necessity" to America's space program. Yep, believe it. Spent a bit of time at Martin trying to figure out how to boost payloads into higher orbits from the shuttle cargo bay (using a recycled upper stage from the Titan project). Made little sense. |
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JohnMcGrew wrote:
Blame it on NASA. If there is a lack of alternative "heavy lift" capability, it's only because over 20 years ago, NASA mandated that all future government payloads be designed around the shuttle, and all alternatives to the shuttle be scuttled. This was in order to make the shuttle a "necessity" to America's space program. That's interesting, since NASA routinely sends payloads into orbit on spacecraft other than the shuttle. The three that I work on (EOS/Terra, EOS/Aqua, EOS/Aura) are all non-shuttle payloads. If I remember right, Terra and Aqua were launched using Atlas Centaur rockets, launched from Vandenburg AFB in California. The reality was that the economics of the shuttle were complete fantasy, and NASA knew it. (hence the mandates leaving the US with few alternatives until the French, Russians, and Chinese started filling the void) We could (and perhaps should have) gone on building disposable Saturn-like boosters (500k pound payloads, vs the shuttle's 30k to 40k). The R&D was paid for, and the support costs would be a fraction. (A typical shuttle mission costs somewhere around half-a-billion) The Shuttle's purpose was more than just lifting payloads. It's both a scientific platform, as well as a on-orbit repair station. -- Jay __!__ Jay and Teresa Masino ___(_)___ http://www2.ari.net/jmasino/ ! ! ! Checkout http://www.oc-adolfos.com/ for the best Italian food in Ocean City, MD and... Checkout http://www.brolow.com/ for authentic Blues music on Delmarva |
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AES/newspost wrote:
Little to completely negligible meaningful science actually done with or on the shuttle; That's a matter of opinion. There's are dozens, if not hundreds of small experiments that are carried out on every shuttle mission that the public doesn't neccessarily know about. I'm sure those scientists feel that their work is worthwhile, and I suspect that the scientific community in general does too. shuttle launches for repair missions of unamnned orbitals cost more than rebuilding and relaunching a new copy of the same item; plus limiting the unmanned orbital to an orbit reachable by the shuttle generally significantly compromises its performance. For a small satellite, that may be true, although the turn around time may be important, depending on the mission. For a large, expensive satellite like Hubble, I doubt that "relaunching a new copy" is a viable short term fix to any problems it might encounter. The next generation space telescope is still several years away. NASA doesn't force a spacecraft team to use a shuttle accessable orbit. Terra, Aqua and Aura can't be reached by the shuttle, and they're worth billions of dollars each. I think, from a shuttle repair standpoint, if a particular satellite can be reached by the shuttle, and if the economics and mission timeline dictates that it's worth repairing, it becomes a canditate for repair. If not, it doesn't get repaired. NASA isn't stupid. -- Jay __!__ Jay and Teresa Masino ___(_)___ http://www2.ari.net/jmasino/ ! ! ! Checkout http://www.oc-adolfos.com/ for the best Italian food in Ocean City, MD and... Checkout http://www.brolow.com/ for authentic Blues music on Delmarva |
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In article ,
AES/newspost wrote: The Shuttle's purpose was more than just lifting payloads. It's both a scientific platform, as well as a on-orbit repair station. Little to completely negligible meaningful science actually done with or on the shuttle; shuttle launches for repair missions of unamnned orbitals cost more than rebuilding and relaunching a new copy of the same item; plus limiting the unmanned orbital to an orbit reachable by the shuttle generally significantly compromises its performance. You can't do much man-in-space science during unmanned missions. Of course, the people who don't want manned missions don't care about that science. -- Bob Noel |
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Jay Masino wrote:
JohnMcGrew wrote: Blame it on NASA. If there is a lack of alternative "heavy lift" capability, it's only because over 20 years ago, NASA mandated that all future government payloads be designed around the shuttle, and all alternatives to the shuttle be scuttled. This was in order to make the shuttle a "necessity" to America's space program. That's interesting, since NASA routinely sends payloads into orbit on spacecraft other than the shuttle. The three that I work on (EOS/Terra, EOS/Aqua, EOS/Aura) are all non-shuttle payloads. If I remember right, Terra and Aqua were launched using Atlas Centaur rockets, launched from Vandenburg AFB in California. That's true, ....today. But by the 80s (hence the 20 years ago) NASA (and the government at large) did mandate that the shuttle would be the platform for all government launches, including military. In addition, the shuttle was supposed to somehow make money with commercial launches for private satellites in the USA, and the rest of the world too. Production was being terminated for Delta, Atlas, and Titan rockets. The design of the shuttle itself reflects this. Remember, the shuttle design had at least as much to do with politics as it did with aerodynamics. In a post Apollo era of massive cutbacks, the shuttle need the DoD's support and funding to get approval by the Nixon administration. To win DoD (Air Force, mainly) support, the cargo bay was built to handle large DoD satellites. The wing design was much larger than what would be optimum for NASA. Why? Because all government launches included polar orbit launches, which were to be launched from Vandenberg AFB. The larger wings were needed for the cross range needed to allow the Shuttle to glide back to Vandenberg (or somewhere else convenient) in case an engine was lost prior to orbit insertion. Also, DoD payloads had very wide measurements. The compromises needed to support the DoD greatly added to the weight of the orbiter. A planned booster engine, which was supposed to provide a one time go-around capability, had to be deleted early on because of these constraints. In addition, and no less importantly, the larger wing design necessitated a much larger thermal cross section in reentry, and also meant the orbiter would be spending much more time in the hottest area of reentry. The tile system was created to meet this requirements. It is ironic that the design constraints not used for today's shuttle are what help to make the shuttle so dangerous. The shuttle would be used for higher altitude (and deep space probe) launches too. How would it do this? Two orbiters, Discovery and Challenger were modified to support the Centaur upper stage, which is a liquid fuel rocket. Ports were added to the orbiters to allow the Centaur to be fueled and vented, plus the necessary controls. Centaur never flew on the shuttle. After Challenger's accident NASA reevaluated the wisdom of liquid rockets in the cargo bay. [TANGENT: The recently demised Galileo probe to Jupiter was originally designed to use the shuttle / Centaur, and after shuttle flights resumed post-Challenger accident, it had no method of launch available. (The revived non shuttle launch program had not been cranked up again yet to support it). So it was launched from the Shuttle, but Venus, Venus (again) and Earth's gravity was used to get the probe to Jupiter in an ingenious roundabout route. After launch the high gain antenna never deployed, possibly because it was in unplanned storage for so long while Shuttles was grounded. The low gain antenna saved the day after new compression software was uploaded to the probe and the entire Deep Space Network was configured to talk to Galileo.] By the mid 80's the shuttle program was getting out of control. The schedule was getting increasingly crammed on the now-declared-operational shuttle. To get enough launch revenue (this made sense to somebody in government fantasyland), launches were to be increased to once a month, and then nearly every two weeks (24 per year). But there were only enough parts for two shuttles. Remember, Challenger's 51L launch was delayed to that cold January morning partly because Columbia's prior 61-C launch was delayed about a month, and parts needed to be flown (via a T-38 IIRC) from the Columbia to Challenger. Columbia's landing was also delayed, due to weather, and it was not able to land at KSC, as originally planned. The ripple effects of one delay in this tight environment could affect the entire launch schedule for 12 months, or more. Every time an orbiter was cannibalized for parts, the risks increased due to exposing them to possible servicing problems. In the end, the shuttle just wouldn't be able to perform at Vandenberg, despite the changes that were made to its initial design for polar launches there. Unlike launches from KSC, Vandenberg polar launches would not benefit from the earth's rotation. KSC launches go in orbit, aided by the boost of the earth spinning to get the craft up to orbit speed. But Polar launches are roughly perpendicular to the earth's rotation, so there is no boost at all. This means that much more power is needed from the engines. An attempt was supposed to be made to develop a lighter solid rocket booster design, but the Challenger accident cut all of this short. After the accident, the Vandenberg shuttle launch facility was mothballed. Only then was the Titan IV (Martin Marietta-now Lockheed Martin) program begun to launch big DoD payloads (and the NASA Cassini spacecraft, due at Saturn on July 4 2004.). The DoD/NASA finally realized that expendable rockets really would be needed, shuttle or no shuttle. Also, NASA got out of the commercial and DoD launch operation business a few years after the Challenger accident. The manufacturers and the USAF took this over. By the way, at Vandenberg, huge structures had been created to shield the orbiter's new pad from prying eyes during DoD missions. Support and vehicle assembly buildings were constructed, and a runway was lengthened to support orbiter landings. Even a seaport was constructed. Vandenberg's first space shuttle launch was to occur mere months after 51-L landed safely. The launch area, SLC-6 or "slick 6" was dogged by poor workmanship and allegations of drug use by construction workers. It was rebuilt to launch Athena, and now Delta IV (Boeing) rockets. By the way, a decision was made to make a set of "structural spares" of large fuselage and tail parts (vertical stabilizer, rudder, wings, elevons, etc) during the construction of Discovery and Atlantis, to repair a fuselage in case there was accident damage. These spares would later be used to build Endeavour. The Challenger accident occurred just before shuttle production facilities were to be ramped down. Also the later shuttles (Discovery, Atlantis, Endeavour) have much fewer thermal tiles, because advances in material technology allowed more thermal blankets on the upper fuselage instead. The reality was that the economics of the shuttle were complete fantasy, and NASA knew it. (hence the mandates leaving the US with few alternatives until the French, Russians, and Chinese started filling the void) We could (and perhaps should have) gone on building disposable Saturn-like boosters (500k pound payloads, vs the shuttle's 30k to 40k). The R&D was paid for, and the support costs would be a fraction. (A typical shuttle mission costs somewhere around half-a-billion) The Shuttle's purpose was more than just lifting payloads. It's both a scientific platform, as well as a on-orbit repair station. That's true, but the design limitations of the shuttle were based on launching military payloads, most of which never launched on the shuttle, and never will. |
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