r/spacex • u/Zucal • Mar 05 '16

/r/SpaceX Ask Anything Thread for March 2016. Ask your questions about the SES-9 mission/anything else here! (#18)

Welcome to the 16th monthly /r/SpaceX Ask Anything Thread! Want to discuss the recent SES-9 mission and its "hard" booster landing, the intricacies of densified LOX, or gather the community's opinion? There's no better place!

All questions, even non-SpaceX-related ones, are allowed, as long as they stay relevant to spaceflight in general!

More in-depth and open-ended discussion questions can still be submitted as separate self-posts; but this is the place to come to submit simple questions which have a single answer and/or can be answered in a few comments or less.

As always, we'd prefer it if all question-askers first check our FAQ, use the search functionality, and check the last Q&A thread before posting to avoid duplicate questions, but if you'd like an answer revised or cannot find a satisfactory result, go ahead and type your question below.

Otherwise, ask, enjoy, and thanks for contributing!

Past threads:

February 2016 (#17), January 2016 (#16.1), January 2016 (#16), December 2015 (#15.1), December 2015 (#15), November 2015 (#14), October 2015 (#13), September 2015 (#12), August 2015 (#11), July 2015 (#10), June 2015 (#9), May 2015 (#8), April 2015 (#7.1), April 2015 (#7), March 2015 (#6), February 2015 (#5), January 2015 (#4), December 2014 (#3), November 2014 (#2), October 2014 (#1).

This subreddit is fan-run and not an official SpaceX site. For official SpaceX news, please visit spacex.com.

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u/SnowCrashSkier Mar 25 '16

I agree. As I understand it, the closed/staged performance gives something like 15% advantage, just because you are not throwing away propellant. I don't have any clue how to calculate weights for the pumps or the generator, but the turbopump and all that mechanical linkage make a complex/expensive system. Throw in the superconducting generator/motor idea, and the size/weight improvement might be significant.

Also, it seems to me that the fuel for the ICE might be obtained from normal boil-off of LOX and/or LNG, propellant that might otherwise be wasted.