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NASA Astronauts Return Home in SpaceX's Crew Dragon Spacecraft [video]

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Re: NASA Astronauts Return Home in SpaceX's Crew Dragon Spacecraft [video]

#71

Post by evv »

m0xte wrote: post #61
TeMPOraL wrote: post #58

Earlier quoted context omitted.

Related, I wonder if there's going to be a postmortem on this mission on the UI, because from the brief scenes when its shown updating or being clicked on, it looks to have a responsiveness on the order of half a second .

Think it’s Electron. Doesn’t surprise me. I wouldn’t want to take slack into space with me.

It is reportedly Chromium-based, not quite electron. UI is HTML with web components. Lots more details here: https://old.reddit.com/r/spacex/comments/gxb7j1/we_are_the_s...

Re: NASA Astronauts Return Home in SpaceX's Crew Dragon Spacecraft [video]

#72

Post by Kliment »

sebazzz wrote: post #62
paranoidrobot wrote: post #34

Earlier quoted context omitted.

There are four parachutes. It's designed to support at least a single-chute failure, I don't know about multiple chute outages. As for propulsive landing - the latest I can see[1] is that while the craft is technically capable of propulsive landing, it's not approved by NASA, even for emergencies. So it's likely that these options are not even available for the crew, and they wouldn't have trained on how to use it/ac…

Not even for emergencies? Does that mean that it is officially not there, but in the unlikely unlikely event it can be used, or that it really isn't there anymore and the capsule would just drop dead on the ground?

It means it's never been tested and there's no safe way to use it - the hardware and software are not configured to have that ability for this particular flight, is how I understand it.

Re: NASA Astronauts Return Home in SpaceX's Crew Dragon Spacecraft [video]

#73

Post by geomark »

gregoriol wrote: post #64
marvin wrote: post #63

Earlier quoted context omitted.

Don't see why you're downvoted for posting this. Certainly, satellites designed before the Space Shuttle would have to be very paranoidly designed to include a self-destruct mechanism, but it only takes a couple kilograms of explosives to strongly disincentivize kidnapping it. If I was a military satellite designer, heaven forbid, I'd definitely include that in a world that included the possibility of stealing satell…

Even without self-destruct, a satellite not programmed to be captured could simply fire some thrusters if it detects an orbit change, and that would likely make some big dammage inside the capturing shuttle.

As part of just normal station keeping it might do that.

Re: NASA Astronauts Return Home in SpaceX's Crew Dragon Spacecraft [video]

#74

Post by martyvis »

kanox wrote: post #3

Not yet, not until re-entry. It's arguably the most dangerous part of the missions since launching on Falcon 9 has happened many times before. Both Soyuz and the Space Shuttle had fatal accidents on re-entry.

The Crew Dragon is very similar to the Cargo Dragon that has already had nearly 20 returns from orbit without incident, so there is already quite a bit of experience in the systems that will be used tomorrow.

Re: NASA Astronauts Return Home in SpaceX's Crew Dragon Spacecraft [video]

#75

Post by martyvis »

pjfin123 wrote: post #16

I can't easily link to it because it's still live streaming but at 4:10 in they seem to be debugging a local internet/HTML error on their iPads. Next level debugging in production.

I love how the ground personnel are checking that that iPad is in "airplane mode". The Dragon isn't an airplane so that might be their problem. ;-)

Re: NASA Astronauts Return Home in SpaceX's Crew Dragon Spacecraft [video]

#76

Post by bserge »

Perseverance also launched a few days ago: https://mars.nasa.gov/mars2020/

Hopefully the landing is just as smooth as Curiosity's.

It would be really cool to see actual, high quality footage of it, but at least there's the simulated renderings. Extremely impressive.

Re: NASA Astronauts Return Home in SpaceX's Crew Dragon Spacecraft [video]

#77

Post by enkid »

ChuckMcM wrote: post #48
whoisthemachine wrote: post #26

Earlier quoted context omitted.

Huh interesting. Do you have sources for that information?

The idea that you could capture a satellite and return it was part of the mission requirements for the original shuttle design. If it was a 'friendly' or 'unfriendly' satellite was left unspecified. It was also limited by the Shuttle's OMS in terms of delta-v so the orbits from which a satellite could be retrieved was constrained.

Seems like it came in handy fixing the Hubble multiple times, but what your talking about was probably overkill for what they ended up using it for.

Re: NASA Astronauts Return Home in SpaceX's Crew Dragon Spacecraft [video]

#78

Post by kl4m »

cheschire wrote: post #9
yesenadam wrote: post #5

The first comment I saw in the live chat was "You people have it wrong, space is flat, not earth".

Well from what I’ve read the observable universe is fairly flat, but I was wondering what if we’re just living in a basin or on a plateau that extends beyond our observable reach? I suck at math though so I’ll just wait for theoretical astrophysicists to tell me interesting things on blogs.

Estimates set the lower bound at 250x the size of the observable universe, according to the limits of measurement of the "flatness" of our local space. https://arxiv.org/abs/1101.5476

Re: NASA Astronauts Return Home in SpaceX's Crew Dragon Spacecraft [video]

#79

Post by elil17 »

adamjb wrote: post #29
one2know wrote: post #24

Earlier quoted context omitted.

The Shuttle was built to bring down soviet spy satellites and spacecraft, so in that regard, it was the best design made.

Including features that are never used is bad design even if they don't compromise every other aspect of the design. What mainly doomed the shuttle was the DoD requirement that the shuttle be able to pluck a satellite from a polar orbit in one orbit, making it necessary to include the massive wings so that it wouldn't be forced to land in the Pacific as the world rotated underneath it.

If they’d used those features it wouldn’t be public knowledge

Re: NASA Astronauts Return Home in SpaceX's Crew Dragon Spacecraft [video]

#80

Post by one2know »

simonh wrote: post #60
one2know wrote: post #39

Earlier quoted context omitted.

I don't have access to classified military secrets, but you don't think they would build a vehicle that could return 15 tons of payload to earth to retrieve US satellites? US could just build and launch a new satellite easier and cheaper than bring one down to fix only to launch it again. Obviously there is the movie about Salyut 7 that depicts the shuttle trying to capture the station. Salyut 3 had a machine gun att…

Back in the 70s spy satellites used film cameras and used to return the film in re-entry capsules. There’s a _really_ good (fictional) move called Ice Station Zebra about a retrieval mission in the arctic that goes wrong. Retrieving the satellite allows you to safely recover the film, and re-equip the satellite with new film and propellant. The latter is important because it’s useful for spy satellites to be able to…

I read something about naval engagements with soviet ships. The US ships were trying to find something underwater before the soviets did while at the same time not alerting the soviet ships as to the location of what they were trying to find. It became clear they were both looking for one of these film canisters that maybe they weren't able to retrieve in mid-air. People today can't imagine the stakes during the cold war.
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