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

SpaceX launch webcast: Orbcomm-2 Mission [video]

spacex.com

Post reply on HN
Print view View original

81–90 of 444 posts

Re: SpaceX launch webcast: Orbcomm-2 Mission [video]

#81

Post by arjunnarayan »

cmsmith wrote: post #50

I must have missed it, but can anyone explain why Orbcomm wants 11 satellites in the same orbit? The stage 2 engine isn't firing in between letting the satellites go.

The satellites have their own thrusters and will use that to reposition. Changing your position within a single orbit is fairly cheap - even if you just go a few m/s, with enough time you can space out quite far.

Re: SpaceX launch webcast: Orbcomm-2 Mission [video]

#82

Post by Animats »

So now how do they secure the booster they landed? Do they have some kind of truck mounted gantry they move into position? There didn't seem to be anything like that near the landing pad. They may want to let the engines cool and any excess propellant boil off before they move in, but they have to have something to hold it, tilt it down to horizontal, and carry it off.

Re: SpaceX launch webcast: Orbcomm-2 Mission [video]

#83

Post by bla2 »

ctdonath wrote: post #56
manaskarekar wrote: post #11

Youtube link for people for whom livestream videos won't work. (I believe the embedded player is livestream). https://www.youtube.com/watch?v=O5bTbVbe4e4

Thanks! Got a link to the replay for those of us tuning in late?

That YouTube link is a replay too.

Re: SpaceX launch webcast: Orbcomm-2 Mission [video]

#84

Post by mikeash »

gregr401 wrote: post #54
cmsmith wrote: post #50

I must have missed it, but can anyone explain why Orbcomm wants 11 satellites in the same orbit? The stage 2 engine isn't firing in between letting the satellites go.

Yes, it absolutely was firing continuously around 17,000 MPH. Doesn't take long at that speed to get some distance between sats.

The satellites are moving at that speed too....

Re: SpaceX launch webcast: Orbcomm-2 Mission [video]

#85

Post by marze »

cmsmith wrote: post #50

I must have missed it, but can anyone explain why Orbcomm wants 11 satellites in the same orbit? The stage 2 engine isn't firing in between letting the satellites go.

The satellites themselves can adjust their individual phasing within the same orbit with minimal propellant.

Re: SpaceX launch webcast: Orbcomm-2 Mission [video]

#86

Post by teleclimber »

tokipin wrote: post #64
kibwen wrote: post #27

Earlier quoted context omitted.

Completely amazing! I'm sure I heard a "holy shit" or two there in the audience. :) EDIT: One question for the rocket scientists here: exactly how reusable do they expect these returned first stage rockets to be? What is the process of certifying that a returned rocket is fit to fly, and what components are most likely to need repairing/replacing with each launch?

This is in the "to be optimized" bracket. If they can get any kind of consistency landing even heavily strained rockets, they can reframe/readjust/redesign as necessary (like adding more support in areas etc).

Exactly. Now that they got one back they can actually start the process of figuring out what needs to be done to make the first stage as reusable as possible. It's a long road, but they can finally make some headway now.

Re: SpaceX launch webcast: Orbcomm-2 Mission [video]

#87

Post by jacquesm »

cornholio wrote: post #71
jacquesm wrote: post #41

Earlier quoted context omitted.

NARS but probably comparable to shuttle engines and body.

The Shuttle engines operate on hydrogen which burns very cleanly. RP-1 will leave the engine dirty with coking, so they definitely need to clean re-assemble each engine. On the other hand, the solid boosters of the Space Shuttle were severely damaged by the impact and corrosion of the sea water, after "recovery" they were essentially a source of parts for new boosters. Overall, I really hope they can improve re-usabi…

They did re-light the engines, curious how many times in a row they can pull that trick before contamination becomes a problem.

Re: SpaceX launch webcast: Orbcomm-2 Mission [video]

#89

Post by JshWright »

cornholio wrote: post #71
jacquesm wrote: post #41

Earlier quoted context omitted.

NARS but probably comparable to shuttle engines and body.

The Shuttle engines operate on hydrogen which burns very cleanly. RP-1 will leave the engine dirty with coking, so they definitely need to clean re-assemble each engine. On the other hand, the solid boosters of the Space Shuttle were severely damaged by the impact and corrosion of the sea water, after "recovery" they were essentially a source of parts for new boosters. Overall, I really hope they can improve re-usabi…

The first stage goes through at least one full mission duration burn and another ignition before finally launching. So they don't need to be reassembled completely between each firing. I assume they have been repeatedly firing engines for a while now to see how many relights they can get.
Post reply on HN