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SpaceX successfully launches two humans into orbit

nasa.gov

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Re: SpaceX successfully launches two humans into orbit

#91

Post by Gwypaas »

dmlittle wrote: post #74

Does anyone know what happens to the 2nd stage engine? Does it stay in orbit or does it eventually fall back to earth/go into space?

Depends on the mission, for something like this it deorbits fairly quickly due to the drag of the low orbit. To geostationary transfer orbit it takes longer but the periapsis (lowest point) is low enough to slowly deorbit it.

Then we have launches straight to geostationary orbits and similar, for those the second-stages will essentially never come down and they end up positioned in a graveyard orbit.

Re: SpaceX successfully launches two humans into orbit

#92

Post by bryanlarsen »

haunter wrote: post #60

I'm actually surprised they use a touchscreen interface, and they will use that for the manual docking too! https://i.imgur.com/YKiqIqO.jpg

There are two rows of physical buttons below the touch screens along with a large manual abort lever. The physical buttons are used for manual docking.

Re: SpaceX successfully launches two humans into orbit

#93

Post by eecc »

NikolaeVarius wrote: post #24
elliekelly wrote: post #16

Earlier quoted context omitted.

Earlier this week when they were de-fueling they mentioned that the "escape system" was still active during that process. Is that because the fuel is potentially dangerous? Tangentially related, can the "escape system" be activated even when the rocket itself hasn't left the ground? I watched the escape system test but IIRC it involved launching and then aborting so the pod that carries the crew was already high off…

Anything involving fuel is dangerous. Demo-2 is first time that humans are on the rocket while its being fueled. The escape system is on while fueling and defueling since those are high risk times for the rocket.

Even when boarding commercial flights, crew tells you not to fasten seat belts if they’re still refueling. Just in case you need to evacuate (of course it’s just a token concern, I would t expect to survive an airplane bursting in flames even if still docked.)

Re: SpaceX successfully launches two humans into orbit

#96

Post by [deleted] »

NikolaeVarius wrote: post #49
avmich wrote: post #43

Earlier quoted context omitted.

I think you can have adequate reliability performance and win on safety with a different choice of propellants. I also think general history of technology - including space technology - supports this point of view.

You're not arguing anything. You're saying "I think something else can be good too". Until you literally give an actual engineering (comparison of performance/reliablity/etc) reason that hypergolics are the wrong choice to make, this is effectively saying that "something should be different because I think so"

[deleted]

Re: SpaceX successfully launches two humans into orbit

#97

Post by johncalvinyoung »

dmlittle wrote: post #74

Does anyone know what happens to the 2nd stage engine? Does it stay in orbit or does it eventually fall back to earth/go into space?

Saw a diagram showing that the 2nd stage should deorbit and splashdown somewhere in the Indian Ocean. Not sure when, precisely, though.

Re: SpaceX successfully launches two humans into orbit

#98

Post by jvanderbot »

ChuckMcM wrote: post #86

It is hard to convey how "sustainable" this feels to me. For the first time, humans have gone into orbit in a spacecraft that was designed from the ground up to be a commercial venture. All of the NASA missions prior to this have an ambience of "uneconomical but useful". Even the shuttle, which was supposed to be this cost effective space truck, turned out to be not even close. And the last thing I'm feeling is the a…

This is what it should have been a decade or two ago. The infusion of expertise from gov-sponsored / R&D to commercial should have been accelerated long ago. Happy to see Lars and others matching up with entrepreneurs and a new generation to get things done.

Re: SpaceX successfully launches two humans into orbit

#99

Post by thepete2 »

manaskarekar wrote: post #10

Good luck to everyone! What an exciting time. Curious about the spacesuits and performance of the “minimal” touchscreen interfaces compared to the older stuff.

I watched the "Everyday Astronaut" Youtube stream where he said that those are IVA suits (as opposed to EVA) and can only hold pressure for a couple of minutes, enough time for the capsule to return safely to earth in case of an emergency.

Re: SpaceX successfully launches two humans into orbit

#100

Post by avmich »

orbital-decay wrote: post #57
avmich wrote: post #20

Earlier quoted context omitted.

Buran had non-toxic components for RCS. Kliper was planned with non-toxic RCS. Soyuz spacecraft at least has non-toxic components for capsule RCS, so when the capsule lands, it doesn't need to be approached in a chemical protection suit. It's not a question of choices - there are choices. I suspect it's a question which is considered less important so far, so SpaceX didn't pay that much attention to it, considering t…

Buran was using LOX, storing it for up to two weeks with a cryocooler and a complicated cooling system, Crew Dragon can be rated for hundreds of days and doesn't have the volume/mass/cost to spare. Dreamchaser with its propane/N2O thruster is a better counterexample. They avoided toxic components so it could theoretically land at any airport, making it a strong selling point. There are also new(-ish) hydroxylammonium…

> Crew Dragon can be rated for hundreds of days and doesn't have the volume/mass/cost to spare.

Mass is often an issue with spaceflight. We're arguing about what's better overall, not what's better by all possible criteria. Crew Dragon I'd say has more mass to spare than earlier spacecrafts - because at least of economy of scale and more mass-efficient subsystems.

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