tag:blogger.com,1999:blog-8809438035746342262.post7468760057374854516..comments2023-10-27T19:34:05.946-07:00Comments on NEW PAPYRUS: Resurrecting the Delta ClipperMarcel F. Williamshttp://www.blogger.com/profile/16245086958213100840noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-8809438035746342262.post-73441795306408857652009-03-11T19:57:00.000-07:002009-03-11T19:57:00.000-07:00Thanks for the comment John. I wish I could have b...Thanks for the comment John. I wish I could have been there to see one of the Delta Clipper flights. <BR/><BR/>But if the Delta Clipper folks aimed too high then Al Gore and NASA aimed-- even higher-- when they chose the Venturestar, a far more complex SSTO vehicle.<BR/><BR/>The military also wanted the Delta Clipper to be a polar orbiting satellite launcher which would have added even more to the complexity when all we really needed was a reusable vehicle that could easily transport a few people into equatorial orbit and back. <BR/><BR/>Its still going to require billions of dollars of dedicated investment to develop a manned SSTO vehicle, IMO.<BR/><BR/>But if such a vehicle is ever developed that can be launched anywhere in the US and in the world, then I think that hundreds, if not thousands, of people will be going into space every year and maybe even to future facilities on the moon-- and a new age of space commercialization and industrialization will have begun.Marcel F. Williamshttps://www.blogger.com/profile/16245086958213100840noreply@blogger.comtag:blogger.com,1999:blog-8809438035746342262.post-14613097025343436512009-03-11T18:18:00.000-07:002009-03-11T18:18:00.000-07:00I was present at the second flight of the DC-X in ...I was present at the second flight of the DC-X in 1993, (the one where it was proved that a rocket could be re-used). The BIG mistake of that program was to aim too high. They should have aimed for a two-stage re-usable rocket program to see how far they could go. The demonstrator had no heat shield and could never have even gone as high as an X-15. It was designed to test the landing and maneuvering capacity of such a vehicle. It was a complete success.<BR/><BR/> The follow-on vehicle could have been designed to carry a second stage, tapered and cone shaped as the first, with the first stage alone being recovered by landing itself just like the DC-X. Imagine how much cheaper rocket launches would be if just the first stage (the largest and most expensive part) was recovered.<BR/><BR/>There are several different ways of recovering the first stage, such as horizontal flyback, vertically on land, parachutes and airbags on land, parachutes into the water, Engine pod recovery only, etc. They all need to be investigated by developing a prototype of each kind to see how well it works and how much of a second stage and payload it can carry if all versions of the first stage are about the same mass.<BR/><BR/>Some existing companies like Space-X and Blue Horizon, are working on this problem, but only a couple of methods are being pursued currently (as far as we know). This would be a very tough and expensive, but incredibly worth-while effort to complete.<BR/><BR/>There is also no guarantee that another government-sponsored program would help or hurt the effort to create a commercial re-usable rocket.<BR/><BR/>John StricklandJohn K. Stricklandhttps://www.blogger.com/profile/08203128609981880162noreply@blogger.comtag:blogger.com,1999:blog-8809438035746342262.post-84703700908613033692009-03-11T16:55:00.000-07:002009-03-11T16:55:00.000-07:00On Mar 9, 9:08 am, dumpst...@hotmail.com wrote:>...On Mar 9, 9:08 am, dumpst...@hotmail.com wrote:<BR/>> "The DC-X was not a meaningful prototype of a working<BR/>> spaceship, but merely the world's most inefficient VTOL<BR/>> aircraft, scarcely more advanced than the "Flying Bedstead"<BR/>> prototypes of the 1950s."<BR/>> <BR/>> Source:<BR/>> <BR/>> http://www.spacedaily.com/reports/The_Cold_Equations_Of_Spaceflight.html<BR/>> <BR/>> I wonder if the "Roton" design would've been any better?<BR/>> Remember that Roton used rotor blades for landing, so<BR/>> you didn't have to worry about keeping the fuel and<BR/>> oxidizer cool during re-entry.<BR/><BR/>The DC-X prototypes were obviously not designed to transport payloads into orbit. They were simply demonstrations of the vertical landing concept for a rocket-shaped vehicle. The next steps would have built ships large enough and with mass fuel ratios large enough to achieve orbit. We already know that the US can build single stage to orbit booster that can achieve orbit. The question is, can that vehicle achieve orbit with the additional heat shielding required for safe return to Earth. <BR/><BR/>Simply increasing the size of the vessel would increases fuel volume relative to structural mass. Replacing liquid hydrogen fuel with a liquid hydrogen-solid methane slush, would reduce the mass of the fuel tanks dramatically. Using kerosene solely for landing fuel might reduce the structure size even further. Replacing passive heat shields and rocket engines with a plug-nozzle design might reduce the structural mass even further. <BR/><BR/>But the principal advantage of a Delta Clipper-like ship is as an affordable people shuttle to transport perhaps 6 to 10 people into orbit. People don't weigh much. So the original Delta Clipper concept goal of lifting ten tonnes into equatorial orbit would be unnecessary. Just 5 tonnes of payload capability would probably be needed to transport 8 passengers plus two pilots into orbit inside of a pressurized passenger compartment. So such a small payload wouldn't be big deal. <BR/><BR/>Obviously, such a vehicle would probably have a much higher capital cost and fuel cost than an expendable rocket. But the dramatic cost savings for such a SSTO vehicle will come from the dramatically reduced labor cost with perhaps only a few hundred personal required to launch and maintain the SSTO vehicle vs. the tens of thousands of personal required to launch and maintain and expendable rocket. <BR/><BR/>Marcel F. Williams<BR/>http://newpapyrusmagazine.blogspot.com/Marcel F. Williamshttps://www.blogger.com/profile/16245086958213100840noreply@blogger.com