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SpaceX test flight of Starship SN-5 [video]

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Re: SpaceX test flight of Starship SN-5 [video]

#91

Earlier quoted context omitted.

Also, since its mostly made from steel, it will be fairly simple (as far as rockets go) to conduct repairs, you just need a welding rod or two. This is important for early stage bases where you don't have the equipment/materials to make carbon fiber or exotic aluminum alloy replacement parts.

Given how much difficulty they've had with welds and materials to date, is it really feasible to conduct in-situ repairs without a ton of advanced equipment?

I feel the same way. Likely not to start but over time I think they would build up capability. I wonder how lesser gravity on Mars would help/hurt their efforts. Easier to heft heavy gear up high?

I'm also thinking on the flip side, say a Starship somehow gets irreparably damaged getting to Mars (but successfully gets there). With some basic gear they should be able to part it out and re-use the steel.

Like for a new door on all the Cybertrucks rollin' around up there. /s

Re: SpaceX test flight of Starship SN-5 [video]

#92
post #75

Earlier quoted context omitted.

The application forms are pretty ridiculous with theIr insistence on school/graduation dates (some reqs) and SAT/ACT scores (all). As a very experienced engineer, I can’t accept being judged on (historical) trivia.

Same here. Understand they need to somehow weed through their applications. Experienced engineers are costly to assess and having a cheap test to remove the obvious negatives helps them at the cost of a few false ones. :-( I'm also not a US citizen, so that's another cheap test I can't pass.

> I'm also not a US citizen, so that's another cheap test I can't pass.

Unlike other "cheap tests", that one is imposed by US government regulations, not SpaceX's own decisions.

I imagine SpaceX would be quite happy if ITAR was loosened, but I doubt that will happen.

I honestly can't see why ITAR applies to citizens of friendly countries such as Canada or the UK. The point of ITAR is to stop unfriendly countries like China, Russia, Iran or North Korea getting access to technologies with sensitive military applications. The US trusts its closest allies in so many other ways (e.g. UKUSA "Five Eyes" intelligence sharing agreement, the 1958 Mutual Defence Agreement under which the UK and US share nuclear weapon design information), why not in this?

Re: SpaceX test flight of Starship SN-5 [video]

#93
post #76

Earlier quoted context omitted.

I recently read the screenplay to 2001. An interesting thing mentioned in the script, but not shown in the film, is that all of the images of beautiful space ships in the early sequence of the film are in fact space-based nuclear missile launchers, and that there are 27 nuclear nations with space weapons. I sometimes imagine what an alien visitor would think about us if they came to our planet and saw that we had suc…

Any sources for this? Wikipedia seems to state there are no known operative orbital nuclear weapons systems: https://en.m.wikipedia.org/wiki/Space_weapon#Space-to-Earth_...

They mean missiles on earth just as we have today, not space based ones.

Re: SpaceX test flight of Starship SN-5 [video]

#94

Earlier quoted context omitted.

Also, since its mostly made from steel, it will be fairly simple (as far as rockets go) to conduct repairs, you just need a welding rod or two. This is important for early stage bases where you don't have the equipment/materials to make carbon fiber or exotic aluminum alloy replacement parts.

Given how much difficulty they've had with welds and materials to date, is it really feasible to conduct in-situ repairs without a ton of advanced equipment?

The difficulty is making it light and strong. If you're doing an emergency patch repair on a small area you could sacrifice some cargo and use much thicker material and more welds to be sure it will hold. It wouldn't be easy but is much easier than the initial build.

Re: SpaceX test flight of Starship SN-5 [video]

#95
post #89

Earlier quoted context omitted.

Having a degree or not is different from having a degree with a low or high GPA. Having a low GPA at a University is a worse signal for hard working person than having no University background.

Does anyone even care what your grades were beyond your first job?

Much less one’s college admission test scores - how do they signal a “hard working person” especially 20 years down the road?

Re: SpaceX test flight of Starship SN-5 [video]

#96

Does anyone else get super depressed by this? I did some great work today. I coded something pretty cool and useful. I built a little deck to explain it. My coworkers loved it. My job security went up. I enjoyed it. The journey is the reward. But these guys are making rockets in tents. Should I be rethinking life? Because that's how it feels. I love it. I admire them. But it feels unobtainable. I want to make that ki…

Making a difference in the world is what counts. It’s the delta that matters, not the final value. Measure what you do by the change in yourself and others, and how it makes society better.

Yeah, preferably that delta is positive.

Re: SpaceX test flight of Starship SN-5 [video]

#97
post #75

Earlier quoted context omitted.

Same here. Understand they need to somehow weed through their applications. Experienced engineers are costly to assess and having a cheap test to remove the obvious negatives helps them at the cost of a few false ones. :-( I'm also not a US citizen, so that's another cheap test I can't pass.

> I'm also not a US citizen, so that's another cheap test I can't pass. Unlike other "cheap tests", that one is imposed by US government regulations, not SpaceX's own decisions. I imagine SpaceX would be quite happy if ITAR was loosened, but I doubt that will happen. I honestly can't see why ITAR applies to citizens of friendly countries such as Canada or the UK. The point of ITAR is to stop unfriendly countries like…

A country is friendly until it isn't. I understand it's not a requirement imposed by SpaceX, but it also prevents them from getting a lot of applications they wouldn't be able to turn into hires.

Re: SpaceX test flight of Starship SN-5 [video]

#98
post #16

What a week for SpaceX! Two days ago they landed Bob and Doug, and now they succeeded to hop a water tower (as a side project nonetheless, AFAIK only a small part of SpaceX is on this team)! Can't wait to see future iterations and improvements of this beast, especially to see more Raptors strapped on!

Elon has mentioned that it’s all hands on deck for Starship. The only resources not on Starship should be focused on making the Dragon secure and certified. https://www.cnbc.com/2020/06/07/elon-musk-email-to-spacex-em...

Re: SpaceX test flight of Starship SN-5 [video]

#99
post #82

Always impressive to me. And I know that people will say "Yeah, basically the only thing 'new' here is the engine" but there are also a bunch of other things that struck me; It did the hop 'off balance' (the final version expects to have 3 raptor engines working together) so the engine out scenario for landing still seems pretty safe. There is something like four more advanced vehicles in the warehouse section at var…

The DC-X still manages to look modern next to it. Had it succeeded, it'd have done something not even SpaceX is doing, which is a fully reusable single-stage-to-orbit craft. I don't think we have the advanced materials for that.

I think the Delta-X could have done the job, what went wrong was letting NASA taking control of it. Remember these are also the people who went with segmented solid fuel boosters, these were the people who thought the VentureStar with three new techs that all had to work at the same time but rejected the designs that did not need as much new tech, these are the people who let the SLS design go forward.

The Delta-X was an interesting design until NASA was involved.

Re: SpaceX test flight of Starship SN-5 [video]

#100
post #38

Earlier quoted context omitted.

Parachutes are a lot fiddlier and less reliable than the layperson assumes, so the baseline for how complex a system like this can be is worse than you'd think.

In my mind, the multiple complex reorientations while falling at terminal velocity — with no plan B — just seems particularly harrowing..

Doing it once is harrowing. Even doing it the tenth or the hundredth time might be harrowing.

Doing it the thousandth time is starting to get old. Doing it the ten thousandth time is business as usual.

The place to improve from is not as good as you may think, "On the Demo-2 mission, NASA has estimated a 1-in-276 chance of losing the crew at some point." Once you have full re-usability, you can fly rockets several orders of magnitude more times. When you're flying that often, you have the ability to work out the kinks.

If instead you limit to what today feels the safest, you might limit yourself from full re-usability and eventually being much safer.

If you want to still go for full re-usability, adding a backup system might actually make things more dangerous: It's another thing that has failure modes. Redundancy can be a double edged sword.

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