#41
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Rand Simberg wrote: Which cuts into your payload weight, and therefore ups your launch price per pound for large numbers of launches. That's an interesting theoretical argument, but in practice, what do you think that Thiokol would do differently in manufacturing a motor for an unmanned launch that they do for a manned one? The recovered SRB segments wouldn't have to meet the strict inspection requirements they now do. After Challenger, Thiokol is probably extremely paranoid about the recovered booster segments it fills and ships. I'll bet any scratches or small dents get the segment rejected, even though they shouldn't really compromise its structural integrity in any significant way. But they'd be far more likely to use something that isn't all bright and gleaming on a unmanned launch. If fact, for warm weather launches, you could use the old style pre-Challenger booster segments without any real problem. Pat |
#42
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#43
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Rand Simberg wrote: I don't see how spending the money to develop a new vehicle that can only be flown a few times because it's using up a finite amount of leftover parts can make any kind of sense. Keep the ETs and SRBs in production; we already have most of the infrastructure built for a Shuttle derived vehicle- we just need a cargo container with 2 RS-68s on the back end and something equivalent to an OMS pod to carry it into orbit- assuming you just don't want to cut the cargo back a bit and put the modified ET itself into orbit for use as parts for a station of some sort- you stick the RS-68's on the back end of the ET, and you can mount a station equivalent to the weight of a loaded Shuttle on the front of the tank, with the ability to use the interior of the ET once in orbit in the way the old "wet" version of the Saturn Workshop was designed to work. Three or four of those will give you a good sized station for your CEVs to go to. In fact, if you have living quarters, cargo, or propellants in sections added to the front end of several ETs, and figure how to refuel them once in orbit, you can send them on an interplanetary trajectory like von Braun's old Mars Fleet. Pat |
#44
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Ed Kyle wrote: The Lockheed design can fly earth orbital missions with just one launch. And, unlike the Russian Kliper design, the Lockheed CEV brings its earth orbit propulsion system home with it. That may or may not be a good thing... We haven't had any particular problems with the Shuttle's OMS pods other than the occasional leaky thruster valve. Nitrous Oxide should be a lot more benign to deal with than the Hydrazine/Nitrogen Tetroxide we've been using. I'm pretty sure the Nitrous oxide could cook off, but so could the Hydrazine for that matter. Pat |
#45
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Chuck Stewart wrote: Sorry, PAT, no conspiracy here. It was quite well known that the military wanted the crossrange for the "once-around" recon sat polar orbit launches from Vandenberg. This gave them a reason to buy into the shuttle, which got the shuttle needed funding. This also drove the large capacity of the payload bay. According to "Rebuilding America's Defenses" one of the key aspects of space usage is to assure U.S. dominance in the space arena; I don't know if the military wants to go to the Moon ala' Project Horizon, but I can guarantee you they would like a manned capability to Earth orbit, and either CEV or Kliper could be turned into a vehicle that has military capabilities given its ability to maneuver in the upper atmosphere. The Russians are supposed to be working on some sort of super MARV that dispenses multiple warheads as it travels at hypersonic velocities in the upper atmosphere (this is probably what Putin was bragging about a couple of months back), and we have also taken steps in that direction with our evolved FALCON Common Aero Vehicle (CAV) project. Both of these systems could have aerodynamics similar to the Kliper/CAV in a scaled-down form; or be full sized unmanned variants if intended to be used as a series of orbiting weapons that can descend into the atmosphere to attack multiple targets via their onboard RVs when a military threat looms. When we got our first look at the BOR unmanned Spiral test vehicle that landed in the ocean, we thought it might be a MARV for attacking carrier task forces. Pat |
#46
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In article ,
Greg D. Moore \(Strider\) wrote: So $60 million for a pair of RSRMs, another $60 million for an ET, say $20 million (WAG) for a boattail and engines (all disposable) and then you still need a standing army for the VAB (to stack all this), the crawler-transporter, crews for pad refurbishment, etc. pretty soon you're talking real money. Exactly. LockMart wasn't going to use *any* of the existing hardware for VentureStar, and they still concluded that it was cheaper to build new launch facilities than to buy into maintaining the LC-39 standing army. -- "Think outside the box -- the box isn't our friend." | Henry Spencer -- George Herbert | |
#47
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In article .com,
Ed Kyle wrote: To me this brings to mind another question: Does the CEV need to be twenty tons? Soyuz was designed in the 60's and weighs seven metric tons. Kliper, proposed as a Soyuz replacement, but able to carry up to six, is projected to weigh 13-15 tons... BAe's Multi-Role Capsule design, done in the mid-80s, with a capacity of four people for normal flight and six in a lifeboat configuration, almost entirely reusable (including propulsion), had an estimated launch mass of 8t including escape tower. -- "Think outside the box -- the box isn't our friend." | Henry Spencer -- George Herbert | |
#48
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Ed Kyle wrote: "http://yarchive.net/space/shuttle/launch_abort.html" Oh, that's pleasant! Did they tell the crew about the little fire problem? Pat |
#49
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Ed Kyle wrote: Kliper, proposed as a Soyuz replacement, but able to carry up to six, is projected to weigh 13-15 tons, but its propulsion system will not be recovered (Lockheed has proposed to make the CEV hardware recoverable). NASA has listed the maximum liftoff mass of CEV, including escape systems and fairings that would not go into orbit, to be 20 tons. CEV doesn't have to weigh that much, of course. Kliper was too heavy for a Soyuz booster, and was to use an uprated Onega booster- a Soyuz booster with a new LOX/LH2 upper stage. This was later changed to the Zenit booster, which means you could theoretically launch Kliper from a modified Sealaunch pad. Pat |
#50
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Pat Flannery wrote:
Still, how long would one have to get it all stuck together? Days or weeks? The Soviet's did a stage (Block D) that used an insulation sunshade for it LOX/Kerosene propellant on Proton-Zond and N-1: http://www.myspacemuseum.com/l1s_2.jpg But do we have any experience with this sort of thing? The closest we came was the canceled Shuttle boosted Centaur stage. I read somewhere that the original Saturn C-1 S-IV stage internal insulation design was selected so that the stage could eventually be used for earth orbit rendezvous missions, where it would be parked fueled in orbit for up to 30 days. The S-IV stage was to have been the Saturn C-2 third stage and the Saturn C-3 third or fourth stage. The internal insulation design carried over to the Saturn V S-IVB stage. - Ed Kyle |
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