Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

SpaceX Crew Demo-1 Mission [video]

spacex.com

Post reply on HN
Print view View original

41–50 of 88 posts

Re: SpaceX Crew Demo-1 Mission [video]

#41

Post by bsaul »

mandeepj wrote: post #37
primordialsoup wrote: post #31

I am an engineer who builds with a computer. And when I see such things as this, I sometimes spend a minute or so marveling and thinking about the complexity of building and orchestrating such a launch. In fact, I really cannot comprehend how something like this can be successfully done, given how so many things could go wrong. Yes, I understand the idea of redundancy, I understand gravity, I understand that physics…

To help you with not feeling overwhelmed - they are doing it since May 6, 2002. It has taken a lot of time, of a lot of people to get here. There was a lot of failures also, along the way.

I remember reading here a document about C programming guidelines for military / space software ( basically no dynamic memory allocation ever), but that was set a long time ago. I wonder if spaceX reinvented some parts of the software stack, or if they went along the traditional way.

I don’t expect seing rust code in the shuttle, but maybe formal proof with custom functionnal languages...

Re: SpaceX Crew Demo-1 Mission [video]

#42

Post by buboard »

primordialsoup wrote: post #31

I am an engineer who builds with a computer. And when I see such things as this, I sometimes spend a minute or so marveling and thinking about the complexity of building and orchestrating such a launch. In fact, I really cannot comprehend how something like this can be successfully done, given how so many things could go wrong. Yes, I understand the idea of redundancy, I understand gravity, I understand that physics…

if we want to be snarky about it, it's basically a computer with rockets and doors attached

Re: SpaceX Crew Demo-1 Mission [video]

#44

Post by danpalmer »

bsaul wrote: post #41
mandeepj wrote: post #37

Earlier quoted context omitted.

To help you with not feeling overwhelmed - they are doing it since May 6, 2002. It has taken a lot of time, of a lot of people to get here. There was a lot of failures also, along the way.

I remember reading here a document about C programming guidelines for military / space software ( basically no dynamic memory allocation ever), but that was set a long time ago. I wonder if spaceX reinvented some parts of the software stack, or if they went along the traditional way. I don’t expect seing rust code in the shuttle, but maybe formal proof with custom functionnal languages...

From what I understand, they are pushing the boundaries on the hardware front, i.e. relatively recent, typical Linux computers onboard, and just relying on having a few redundant ones and short flight times, rather than very radiation hardened systems like those used in satellites or real-time operating systems.

However on the SpaceX software side I think they’re fairly conservative and “boring”, so I’d guess C and similar guidelines to what you’ve mentioned.

Re: SpaceX Crew Demo-1 Mission [video]

#46

Post by boris »

primordialsoup wrote: post #31

I am an engineer who builds with a computer. And when I see such things as this, I sometimes spend a minute or so marveling and thinking about the complexity of building and orchestrating such a launch. In fact, I really cannot comprehend how something like this can be successfully done, given how so many things could go wrong. Yes, I understand the idea of redundancy, I understand gravity, I understand that physics…

This comes down to the cost of failure. If your app crashes or hangs sometimes, some of us might get annoyed but in the end we are all used to this now. It's a different story if your engine blows up from time to time. I am sure if every failure meant a 6 month and a million dollars setback, we would be designing software differently.

Re: SpaceX Crew Demo-1 Mission [video]

#47

Post by laliberte »

primordialsoup wrote: post #31

I am an engineer who builds with a computer. And when I see such things as this, I sometimes spend a minute or so marveling and thinking about the complexity of building and orchestrating such a launch. In fact, I really cannot comprehend how something like this can be successfully done, given how so many things could go wrong. Yes, I understand the idea of redundancy, I understand gravity, I understand that physics…

Agree. Amazing accomplishment by SpaceX, cannot fathom how many things could have gone wrong, and yet they persevered anyway.

Re: SpaceX Crew Demo-1 Mission [video]

#49

Post by Gravityloss »

primordialsoup wrote: post #31

I am an engineer who builds with a computer. And when I see such things as this, I sometimes spend a minute or so marveling and thinking about the complexity of building and orchestrating such a launch. In fact, I really cannot comprehend how something like this can be successfully done, given how so many things could go wrong. Yes, I understand the idea of redundancy, I understand gravity, I understand that physics…

Computer engineering is new. We're still at the phase where bridges collapse and ships sink regularly.

Re: SpaceX Crew Demo-1 Mission [video]

#50

Post by sandworm101 »

simonh wrote: post #39
jessriedel wrote: post #35

Earlier quoted context omitted.

Anyone know why they choose a launch time and trajectory such that the arrival at ISS is more than a day later? It seems like you could choose to arrive at the ISS almost immediately after reaching orbital velocity if you wanted.

They don’t reach the stations orbital velocity immediately after launch though. What they do is launch into a lower orbit behind the station. Lower orbits have a shorter orbital period, so they gradually catch up and raise their orbit as they get closer. If the went into a ballistic trajectory directly at the station, there is a risk of debris from the launch, such as paint flecks, scraps of metal, etc hitting the st…

Technically they do reach the stations velocity. In fact they exceed it. The lower orbit is slightly faster. Total energy is lower, but they are moving faster than the station.

A counterintuitive part of spaceflight is that often you have to first accellerate in order to slow down.

Post reply on HN