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The software that flies SpaceX rockets and starships

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Re: The software that flies SpaceX rockets and starships

#21

Post by jve »

bob1029 wrote: post #16
mattlondon wrote: post #5

Interesting that they are doing updates at only 10 and 50Hz. I had kinda assumed they'd be looking at much higher frequencies for telemetry especially for things like the rocket motor metrics

50Hz is pretty damn fast for anything happening at rocket ship scale (i.e. gimbaling of engines). 10Hz seems fine for a more strategic roll-up of all subsystems wherein you would have to do more complex logic each round. The physics are pretty stable at any rate considering the masses involved. If we were talking about controlling a 10g nanodrone (hypothetically), 50hz would probably be cause for concern. For a Space…

> 50Hz is pretty damn fast for anything happening at rocket ship scale

I was thinking whether this is OK for dragon in-flight abort system. Well, probably is. Or that may use some system on Dragon itself as the rocket may be no more...

Re: The software that flies SpaceX rockets and starships

#22

Post by awestroke »

chinathrow wrote: post #12
sgt wrote: post #4

They're not running a dependency-ridden NodeJS backend with MongoDB and random cloud services? How are they even able to get to space?

Well... https://twitter.com/tobi/status/1266867215325974528

That's the frontend. It's fed data by the main computer, but if it crashes nothing else is affected.

Re: The software that flies SpaceX rockets and starships

#24

Post by chinathrow »

awestroke wrote: post #22
chinathrow wrote: post #12

Earlier quoted context omitted.

Well... https://twitter.com/tobi/status/1266867215325974528

That's the frontend. It's fed data by the main computer, but if it crashes nothing else is affected.

If it crashes and Dragon is in manual mode, then what?

Re: The software that flies SpaceX rockets and starships

#25

Post by awestroke »

chinathrow wrote: post #24
awestroke wrote: post #22

Earlier quoted context omitted.

That's the frontend. It's fed data by the main computer, but if it crashes nothing else is affected.

If it crashes and Dragon is in manual mode, then what?

How would I know? However, if you could think of that scenario, you can be 100% sure spacex thought of it over a decade ago and have measures to handle that situation

Re: The software that flies SpaceX rockets and starships

#26

Post by HPsquared »

dotancohen wrote: post #10

> ...when you plan to reuse booster rockets and shuttles on future missions. Shuttles? I'm aware of the general term shuttle as a vehicle for going back and forth, but here I'm certain that the better term would be craft, capsule, or Dragon. Certainly not shuttle.

Does that include the Starship?

Re: The software that flies SpaceX rockets and starships

#27

Post by jve »

chinathrow wrote: post #24
awestroke wrote: post #22

Earlier quoted context omitted.

That's the frontend. It's fed data by the main computer, but if it crashes nothing else is affected.

If it crashes and Dragon is in manual mode, then what?

How about a response from SpaceX software guy that works on Dragon software, including these displays:

> Dragon is a fully autonomous vehicle, so it is capable of completing the trip to and from the ISS without any interaction from the crew. But the displays and button panel do provide the crew with capabilities should they need to take action due an unexpected scenario or emergency. As for the tablets and displays, the tablets themselves act as a sort of backup, and include copies of important data such as procedures. The displays themselves are designed to be fully redundant, so if a single display failed, the other 2 could fully take its place. Even if we were to experience a failure of all 3 displays, the crew has a button panel that can be used to initiate emergency responses, and ground commanding is also possible. > -Jarrett

https://old.reddit.com/r/spacex/comments/ncj4vz/we_are_the_s...

Re: The software that flies SpaceX rockets and starships

#28

Post by fallingmeat »

Interesting they seem to ad-hoc the lifecycle processes, or at least no mention of any industry standards mandatory (RTCA/DO-178C, ISO26262 or even sys eng like SAE ARP4754, etc). Also, no talk of formal methods (formal modeling or formal verification, a la DO-333 with something like Simulink Design Verf or TLA+). Works for them obviously!
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