tag:blogger.com,1999:blog-192883022973901942.post2751635800915953025..comments2023-10-08T02:46:24.823-07:00Comments on Bootstrapping Space: Back (from outer space)Chris Wolfehttp://www.blogger.com/profile/11247630943891521469noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-192883022973901942.post-31090595501106331302016-01-08T14:09:54.869-08:002016-01-08T14:09:54.869-08:00Reusing the upper stage is a much rougher problem ...Reusing the upper stage is a much rougher problem to solve without orbital infrastructure.<br />If you can't rely on anything but what you take with you then the second stage needs a reentry heatshield and quite a bit of leftover dV, both of which come with a heavy mass penalty. You also have to use your vacuum-optimized nozzle deep down in the muck, overexpanded and perhaps unstable.<br /><br />Several options would be available given appropriate services / facilities in orbit:<br />The engine could be scavenged and reused for building chemical tugs. (Not terribly useful, but better than nothing. The fuel tanks could be repurposed for storage as part of a depot.)<br />Heatshields could be built using lunar or asteroidal materials and delivered in orbit. (Good example of a potential early market for lunar products.)<br />Momentum exchange tethers could be used to capture much of the orbital energy of the stage, allowing it to deorbit with minimal propellant. (That energy would be used to boost other payloads from LEO to higher orbits.)Chris Wolfehttps://www.blogger.com/profile/11247630943891521469noreply@blogger.comtag:blogger.com,1999:blog-192883022973901942.post-34857662483521979572016-01-06T10:51:50.185-08:002016-01-06T10:51:50.185-08:00Sadly Musk hasn't shown much enthusiasm for ci...Sadly Musk hasn't shown much enthusiasm for cislunar infrastructure. Mars seems to be his focus to the exclusion of everything else. But re-using just the booster is not sufficient to realize his goals. To have affordable MCTs he also needs to re-use the upper stage. It's my hope he'll come around to recognizing benefits of orbital infra-structure in our earth moon neighborhood.Hop Davidhttps://www.blogger.com/profile/12923433894475072056noreply@blogger.com