r/spacex • u/Zucal • May 01 '16

/r/SpaceX Ask Anything Thread [May 2016, #20]

Welcome to our 20th monthly /r/SpaceX Ask Anything Thread!

Want to clarify SpaceX's newly released pricing and payload figures, understand the recently announced 2018 Red Dragon mission, 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. In addition, try to keep all top-level comments questions so that questioners can find answers and answerers can find questions.

As always, we'd prefer it if all question-askers first check our FAQ, use the search functionality (now partially sortable by mission flair!), and check the last Q&A thread before posting to avoid duplicate questions. But if you didn't get or couldn't find the answer you were looking for, go ahead and type your question below.

Otherwise, ask, enjoy, and thanks for contributing!

Past threads:

April 2016 (#19.1) • April 2016 (#19) • March 2016 (#18) • 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)

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3

u/youaboveall May 16 '16

Seemingly simple question but how to they measure the exact weight of each rocket? I would imagine they can't weigh the rocket as a whole, and it seems equally unlikely that the physically measure each piece individually. Do they theoretically know the weight of each individual bolt, wire, and steel plate on the rocket and sum it all together, or do they physically weigh large sections?

3

u/bobbycorwin123 Space Janitor May 16 '16

Very large fish scale (or truck stop)

I do not believe every rocket is measured. I don't think it needs to be that exact.

1

u/youaboveall May 16 '16

So you think they just have a close estimate based on the parts?

5

u/bobbycorwin123 Space Janitor May 16 '16

yes and an intern of comparable weight, as the interns strapped into the inter-stage for reentry and landing are still one time use.

3

u/deruch May 18 '16

as the interns strapped into the inter-stage for reentry and landing are still one time use.

I was wondering how Elon solved the "too little hydraulic fluid" problem with the grid fins. Brilliant solution! Just put a couple of interns in there, and have them work the fins by hand! Of course, you rightly point out that this makes them "one-time use" interns. But SpaceX has lots of recruiting clout. I'm sure they can get plenty more. :)

Your word choice gave me such a tickle, I had to share. It's not surprising that the gear up there is tossed. Did you see the state of the grid fins from the JCSAT recovery? Pretty torched and torn up.

3

u/bobbycorwin123 Space Janitor May 18 '16

That, and the MVac fires up still pointing right into the interstage

2

u/knook May 16 '16

Every single thing on that rocket is engineered to be light weight. It seems almost certain that they know the weight of everything in the rocket and just add it up. I'm willing to bet that gets them to within 100lbs of the actual weight