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<br /><br />>X-33/Venture Star was not a Shuttle replacement. Combined (sc)ramjet-rocket engines are probably the only way to be Single Stage to Orbit work, but I suspect that the payload delivered to orbit will be too small for a Shuttle replacement.<<br /><br />Oh! I'll obviously bow to your far superior knowledge, but I thought the VentureStar was to work alongside the Shuttle with a view to replacing? (Obviously I'm wrong) <img src="/images/icons/frown.gif" /><br /><br />I know her primary focus was to offer cheaper payload costs to space, but I thought the redesign offered twice the payload space? (the humpback looking redesign by Lockheed Martin).<br /><br />She was a flying fuel tank, granted <img src="/images/icons/smile.gif" />
Uhm, you must be refering to the X20X, a 4 place version of the Dynasoar. A good example of a workable shuttle design. (Optimized crew and pax, cheap to keep, with good preformance.)<br /><br />At stake is the next manned launch vehicle AND its mission. My fear is that even if a machine like X20X were built, it would consign us to the status quo of low earth orbit. Where as an Apollo type capsule, say the NASA prefered 5% Apollo of the earily 90s, gives us the option of at least going to moon. <br />(Based on todays technology, the Mars mission would require something bigger, better, stronger.) <br /><br />The question then becomes; How do we get a reluctant congress to fund two vehicles? Or can we get Boeing, the prodgentor of X20,and owner of the design, to build it as a commerical venture? Then can we get congress to front for the other, (the capsule)?<br /><br />Regards.
><i>I thought the VentureStar was to work alongside the Shuttle with a view to replacing...</i><p>VentureStar wasn't going to be crewed, that by itself means it couldn't be a Shuttle replacement. Also, the payload kept dropping and dropping as they realised SSTO was hard to do.</p>
There is no good reason that we can't have SSTO today. The only reason for the delay in the developement of such craft is the same reason our government still uses punch card polling booths, stand alone computers, and a bureaucracy that still uses colonial secretaries to copy by hand what one could use a Xerox machine to complete. It's called the complacency of the Status Quo.... <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>
<font color="yellow">"How about we say the reason is that it beyond current technology."</font><br /><br />Then we would be kidding ourself.<br /><br />Take a balloon tank Atlas (<i>50 years</i> old technology), rig it up with any modern LOX/kerosene engines (russian would be the best choice due to their experience with them) and there is your SSTO. Just take a look at the abysmal Isp numbers of the original engine, modern beat them by at least 50 sec and are lighter so you don't need the half-staging. It would still be smart to do so.<br /><br />marcel_leonard hit it right on the money, others have pointed this out too, in the other redesign thread:<br /><br /><font color="yellow">"falstaffe - Probably the #1 component that you could change about the shuttle to reduce the cost of a replacement vehicle would be to make it a project of the commercial sector, not the government. Take out the politics, the pork-barrel deals, the military requirements, the multiple layers of beurocracy, and you've already cut your costs in half.<br />"</font><br /><br /><font color="yellow">"nacnud - Get NASA out of building vehicles and instead let them concentrate on designing missions. Get NASA to buy launch capabilities from private firms and let private enterprise decide how best to meet the needs."</font><br /><br />As long as the next shuttle/CEV/whatever is a product from the same old NASA-Congress-BoingLMBigBoys triangle the tax payers are going to get very poor bang for their billions. Technical common sense is lobbied away and the cargo bay is full of pork barrels.
Hey I said that was one of the options available, not necessarily the solution. I was trying to list the different possibilities available from business as usual to that at the extreme end.
Yes, you may blame me for choosing this option as a solution because obviously it's better than business as usual and IMO the best.
I'm not blaming anyone, I was just saying that the quote was from a list of options, I don't know which one, if any, would be the best to pursue. Once an option is chose I have ideas about it but I left the choices of which option to others.<br /><br />It just was a little out of context, OK?
<font color="yellow">"It just was a little out of context, OK?"</font><br /><br />OK perhaps a little, sorry for that. Should have quoted you better but rushed because so much agreeing with that option <img src="/images/icons/wink.gif" /><br /><br />Your option was number four, here are the first three:<br /><br /><font color="yellow">1) Keeping the shuttle as is but upgrade the system to improve turnaround, ie electric actuators instead of hydraulic, non-toxic RCS etc. <br />2) Keep the new vehicle compatible with current system but completely redesign obiter with the experience gained over the last 30 years, this includes shuttle c type options. <br />3) Start again from scratch.</font><br /><br />From option 4 one can assume that in 1,2 and 3 NASA (and maybe AirForce) is still heavily involved and the decision making remains the same chaotic messy lobbying. That alone makes option four the best.<br /><br />Another question is what the new player would choose from 1-3. It's not necessarily start from the scratch. Could be all composite STS-compatiple from Scaled Composites featuring active cooling, 50t cargo capasity and DVD-player.
In some ways, this discussion reminds me of accounts of the debates that occured when aviation began to evolve into metal skinned and framed aircraft. Engine technology was still very primative, and the additional weight of metal frames and skins resulted in performance penalties compared to similiar aircraft of 'conventional' design. Retractable landing gear was far too heavy and complex to even consider being used on aircraft. Pressurizing the cabin required excessive weight if the cabin were not to explode after a few flights at altitude. Water cooled engines were considered more powerful, and more reliable, and there was resistance when air cooled engines began to displace the water cooled engines.<br /><br />We are still in the dawn of space flight, trying to figure out things that we have not had much ability to test. I maintain that there are no reliable figures on payload to orbit costs, because we have never used a simple, mass produced launcher repeatedly over a period of several years. Until such time as we do, we are looking at wildly skewed costs. I remember hearing back in the late 1980's that the Soviet Union was able to get launch costs down around $500 a pound. This was when they had more launches in any given month than we would schedule in a year. Many people felt that the cost figures were distorted because of the military involvement in the space program, and the incredible disparity between the U.S. and the U.S.S.R. in standards of living. But I believe that the Soviet program probably was reaching that level of efficiancy, because it was not a program built around short-term goals, and hand-made hardware.<br /><br />In many ways, the United States space program has almost been designed to incur the highest possible costs, through lack of sustained funding for the life of a program, as well as small numbers of missions using a given booster or capsule. Everything is special order, custom designed, individually milled, etcetera, etcetera. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>
Can I get a amen? <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>
For a post that starts off with a historical analogy -- you're doing a whole lot of re-writing of shuttle history here.<br /><br /><font color="yellow">"But we have learned a great deal from the shuttle, which is the real reason that it got built, I think."</font><br /><br />We have learned a great deal from the shuttle, true. We also sacrificed a whole lot of years without any manned flights to do it, and the flight rate of the shuttle has never been huge. Are you under the impression that if we had continued the Apollo program -- improving the capsule as new technology became available and been modifiying it over 30 years, that we would not have learned as much (and had a 6-10 person capsule by now)? Because the capsules are so small, every time something revolutionary was discovered -- a brand new one could have been built with the latest tech. This is simply not possible given the size and cost of the orbiters. For a comparable cost of the Shuttle program -- we'd have had about five times the number of launches of capsule-style spacecraft -- at a <b>minimum</b>. Would this not have helped out with the volume launch ideal that is one of your primary mantras? <br /><br /><font color="yellow">"No one really expected that the shuttle would be the only launch vehicle we had for years and years, and I am certain that the engineers who came up with the idea of a reusable lifting body for the main structure of a launch vehicle thought of it as a prototype, which would fly for a few years before being replaced with a newer vehicle, which incorporated what we had learned. "</font><br /><br />Major history re-write here. In the early days of the shuttle it was being proposed to launch everything -- commercial, scinetific, and military and do so for costs a fraction of the price of 'conventional' launchers. It was sold as the workhorse (the 'truck to space' comes to mind) that would propel the US space program into the next century. I recall reading
<font color="yellow">Major history re-write here. In the early days of the shuttle it was being proposed to launch everything -- commercial, scinetific, and military and do so for costs a fraction of the price of 'conventional' launchers.</font><br /><br />Not true I'm old enough to remember when the Nixon administration tried selling the shuttle as a cost effective SSTO for NASA... <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>
<font color="orange">"Major history re-write here. In the early days of the shuttle it was being proposed to launch everything -- commercial, scinetific, and military and do so for costs a fraction of the price of 'conventional' launchers. "</font><br /><br /><font color="yellow">"Not true I'm old enough to remember when the Nixon administration tried selling the shuttle as a cost effective SSTO for NASA... "</font><br /><br />Aside from the fact that the shutlle isn't, and has never been proposed to be, an SSTO craft -- what point exactly are you trying to make? The shuttle was indeed started during the Nixon administration -- a fact we both seem to agree on. It was being hyped as a cost-effective means of getting to orbit -- again we seem to agree here.<br /><br />I don't know what you think you mean about the SSTO part -- I can't really agree with you there. Are you arguing that the Nixon administration was selling the shuttle as a cost effective means for getting to orbit -- but <b>not</b> to actually take commercial, scientific, or military payloads when it went?
<font color="yellow">I don't know what you think you mean about the SSTO part -- I can't really agree with you there. Are you arguing that the Nixon administration was selling the shuttle as a cost effective means for getting to orbit -- but not to actually take commercial, scientific, or military payloads when it went? </font><br /><br />By this I mean they originally sold it as a single stage to orbit craft; which was the original agenda for the shuttle. All I'm saying is that somewhere during the late 70's; midway thru the 80's we dropped the ball, and have been dribbling ever since... <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>
How about this: A geo-stationary space tether that only descends to the altitude attainable by Spaceship One? Launch Spaceship One from equatorial facility under space tether . As Spaceship One reaches top of it's near vertical trajectory, manuveur and dock with space tether. This will be your vehicle, it will take you anywhere you want to go. Most difficult portion of space tether to build is the lowest 100 km, so don't bother. <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>
<font color="yellow">Most difficult portion of space tether to build is the lowest 100 km</font><br /><br />Why?
Hurricanes, lightning, aircraft, jetstream, etc. <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>
To avoid bad weather there could be a climber that reels in the tether while going up. It would float high above most of the atmosphere maintaining careful balance, it's weight would be tuned to be the same as tethers pull upwards, finetuned using ballast and perhaps small balloons. When things are safe it would return back to ground/sea unwinding tether as it descends.
mrmorris,<br /><br />From what I can remember, the space shuttle was originally proposed as a small vehicle to carry personnel to orbit, to be used in conjunction with step-rockets, which would carry the cargo. This was in the late 1960's, when it had become apparent that public sentiment had turned against the throwing away of large rockets on every mission.<br /><br />The budget cuts of the early 1970's forced NASA to seek a partner in the construction of the shuttle, the U. S. Air Force. However, the Air Force requirements demanded a total redesign of the vehicle, from a small, totally reusable craft to a huge launch vehicle, which had to use external boosters and a drop tank to acheive orbit.<br /><br />At this time, if I remember correctly, NASA was faced with either coming up with something new, or ending manned space exploration. There was no more money for expendable launch vehicles. There was no more money for task forces to recover capsules. The choice was not between capsules and winged spaceships, it was between flying a new vehicle, or staying on the ground.<br /><br />All through the '70's talk about a space station to be built with the space shuttle kept hopes for a greater manned presence in space alive. Perhaps, if that had happened in a timely manner, the NASA budget would have grown enough to absorb the high costs of operating the shuttle. But with no space station, the shuttle had no where to go, and attention was focused on how expensive it was to fly.<br /><br />Certainly, a robust space program, adequately funded, would have made many advances in capsule technology, if Congress had choosen to emulate the Soviet Union and build rockets in large numbers. Instead, we choose to advance the technology of space access, in the hopes that the space program would regain its prior popularity, with the commensurate increases in funding. But the future is not important enough, so we lost out.<br /><br />Decisions were made in the late 1960's and early 1970's <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>
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