Michael Bloxham - 13/11/2007 8:07 PMWhat about clustering smaller rockets in parallel to allow for the occasional oversized payload?Boeing envisions this for the Delta IV: A first stage consisting of 7 CBC's clustered together is their ultimate configuration. A configuration like this might be capable of lifting more than 7-times as much as a Delta IV Medium with just one CBC ("more than" due to the advantages of parallel staging).I used this as inspiration for my PARIS VII rocket, which envisions a cluster of 7 Ares V-derived tanks to allow for payloads of over 500 tonnes:http://cleanslate.editboard.com/free-chat-f1/paris-launch-system-t11.htm
meiza - 2/11/2007 1:38 PMJust mentioning that bigger is not always the most cost effective approach. It depends on a lot of details.
Michael Bloxham - 14/11/2007 11:07 AMBoeing envisions this for the Delta IV: A first stage consisting of 7 CBC's clustered together is their ultimate configuration. A configuration like this might be capable of lifting more than 7-times as much as a Delta IV Medium with just one CBC ("more than" due to the advantages of parallel staging).
publiusr - 16/11/2007 11:17 AMQuotemeiza - 2/11/2007 1:38 PMJust mentioning that bigger is not always the most cost effective approach. It depends on a lot of details.And smaller is certainly not always the most cost effective approach--otherwise we'd ship oil on thousands of bass boats than in supertankers--that may very well be a harder build than Sea dragon--a simple tube. We just have to get rid of this bias that LVs cannot grow in size--while airplanes and ships continue to grow.
tnphysics - 9/9/2007 1:34 AM Higher frequency gammas are much more damaging than lower.
Has anyone thought of the problems involved in designing an LAS for a spacecraft to go on top of Sea Dragon?I don't think that you can pull someone from on top of a medium-sized nuclear weapon to safety in about two seconds.
It will be cool if someone would build something like the Sea Dragon. I don't think it's fair to say that it is too big just because the Saturn V and Space Shuttle have no market. Obviously, those are both really complex and thus expensive launch vehicles which are made even more so because they are intended to carry human cargo.I would suggest, though, that those two vehicles didn't last because they are in the wrong payload lift range. They are too big for all current applications, yes, but they are too small and too expensive to make a first generation space based industry feasible. If you could put 2 million pounds into LEO with one of these things at a cost of 200 million dollars, and launch twelve of them per year, then space based solar power would suddenly be a lot more reasonable. This is an option that is every bit as cheap as using propellant depots if your goal is eventually to mine gold and vanadium out of asteroids.On another note, for as many formal analyses as were done on this, and for as much enthusiasm as some people have for this rocket, I can find precious little documentation regarding it. I have seen the Wikipedia entry, the Encyclopedia Astronautica entry, the Truax website, and some page that says "Lots of pictures. Loads slowly, but worth it." But none of these sites seem to include any information on the method of guidance and control, for example. Was this vehicle supposed to use liquid injection for thrust vectoring? I doubt an engine that big was supposed to gimbal.How were the engines to be cooled, if at all?What type of propellant injector was assumed?I've known about this concept for over a decade, but these are things (mostly about the engines) I have just never been able to find with a casual internet search.
SeaDragon Documentshttp://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19880069339_1988069339.pdfhttp://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19880069340_1988069340.pdf