Satellite burns up following SpaceX rocket glitch • Hacker News Board

Re: Satellite burns up following SpaceX rocket glitch

#31

Post by ramidarigaz » Sat, Oct 13, 2012, 12:11 AM UTC

tarice wrote: post #25

ramidarigaz wrote: post #14

Earlier quoted context omitted.

The beginning being as soon as they knew their satellite had been deposited well below the desired altitude. If the F9 engine hadn't failed, they wouldn't have needed to do an orbit raising maneuver at all and there would have been no risk of the satellite deorbiting.

A orbit raising maneuver was always necessary to get the satellite to its target. Relevant sections: > "Orbcomm had planned on reaching an altitude of 466 miles above Earth..." > "Due to the engine shutdown, the Falcon 9 used slightly more fuel and oxygen to reach Dragon's intended 202 mile- (325-km) high orbit. Over the next 2.5 days, Dragon flew itself to the station's orbit 250 miles above Earth. It reached the $1…

Right. They were hoping the F9 upper stage would do that orbit raising for them (the non-risky version). The risky part was trying to do an orbit raising with the satellite's onboard fuel, which was the only option after the F9 lost an engine.

The expected outcome (F9 upper stage doing the raising) was considered non-risky, and I'm sure that's the premise the insurance company was operating under when they agreed to insure the satellite.

Re: Satellite burns up following SpaceX rocket glitch

#32

Post by vl » Sat, Oct 13, 2012, 12:12 AM UTC

alanh wrote: post #3

Wow, I hope everyone reads the article before commenting. It’s still amazingly successful. There was a 95% chance the satellite would have made it if they tried, but they were obligated not to try if there were less than a 99% chance of success. (The reduced chance was due to the loss of one of the 9 engines.) And, of course, the primary mission to the space station was fully successful (the engine glitch notwithstan…

It's unclear to me what is the risk to ISS. Secondary payload was on the much lower orbit, and even if it was on the same orbital plane, they could just slightly change orbit plane, and try to raise the obit with any chance of success entirely safe for ISS.

Re: Satellite burns up following SpaceX rocket glitch

#33

Post by tsotha » Sat, Oct 13, 2012, 12:15 AM UTC

tarice wrote: post #18

waterlesscloud wrote: post #12

Earlier quoted context omitted.

Without knowledge of their premiums, it's difficult to judge what sort of deal it was.

If the mission had succeeded, they would've been able to test it a little longer and then received 0 money back. Early test termination yields $10 mil. Either way they're still paying the premiums. I have a feeling, though, that the premiums will be going up after this.

Maybe. The launch manifest lists "ORBCOMM - Multiple Flights" between 2012 and 2014. Their insurance will probably go down if their sats are the primary payload.

Re: Satellite burns up following SpaceX rocket glitch

#34

Post by tsotha » Sat, Oct 13, 2012, 12:17 AM UTC

vl wrote: post #32

alanh wrote: post #3

Wow, I hope everyone reads the article before commenting. It’s still amazingly successful. There was a 95% chance the satellite would have made it if they tried, but they were obligated not to try if there were less than a 99% chance of success. (The reduced chance was due to the loss of one of the 9 engines.) And, of course, the primary mission to the space station was fully successful (the engine glitch notwithstan…

It's unclear to me what is the risk to ISS. Secondary payload was on the much lower orbit, and even if it was on the same orbital plane, they could just slightly change orbit plane, and try to raise the obit with any chance of success entirely safe for ISS.

It's probably mostly a theoretical risk. On the other hand, I recall a flight to Mir that ended up slamming into the station. And NASA doesn't have any reason to accept a risk that doesn't benefit its operations.

Re: Satellite burns up following SpaceX rocket glitch

#35

Post by 46Bit » Sat, Oct 13, 2012, 12:18 AM UTC

United857 wrote: post #21

Did the satellite self-destruct or something? The article seems to imply the rocket and payload reached its first goal orbit of 202 miles (to deliver another separate payload to the ISS). At that altitude, while short of the 466 miles desired, it still should have taken months or years for the orbit to decay and re-enter the atmosphere!

The launch would be to an orbit that would decay in a short-ish time (perhaps fairly elliptical?), since SpaceX wouldn't want to leave the second stage up there long term as yet another large piece of space debris.

Talking from the knowledge of a hobbyist here though, rather than an expert on such matters, so probably wrong on some counts.

Re: Satellite burns up following SpaceX rocket glitch

#36

Post by confluence » Sat, Oct 13, 2012, 12:21 AM UTC

> Among the Dragon's cargo was a freezer that will be used to store scientific samples. For the ride up, SpaceX stashed chocolate-vanilla swirl ice cream inside.

Just awesome.

The mission was a success. The satellite maker's loss was covered with insurance money, the ISS stays up in the sky, engine-out capability proven, subsequent launch contracts remain in place from both NASA/the satellite maker - and the ISS astronauts get home-made chocolate ice cream! Win-win-win.

The only entity that got screwed was the insurance company, but that was a risk they were willing to take and were duly paid for doing so.

Re: Satellite burns up following SpaceX rocket glitch

#37

Post by jamesmcn » Sat, Oct 13, 2012, 12:30 AM UTC

Assuming that the insurance company actually pays out, this seems like a win for both SpaceX and OrbComm. SpaceX got a paying commercial customer, and had an opportunity to test out yet another part of the Falcon stack. OrbComm got a bit of testing time on their new communication platform at less than the cost of a full launch. If the insurance company is structured properly, this is a loss for them, but will average out over time.

Compare with the age of sail, where a mission was considered successful if one the ships actually returned. Even with 75% of the crew dead and 25% toothless and malnourished from scurvy and other ailments.

Re: Satellite burns up following SpaceX rocket glitch

#38

Post by mikeash » Sat, Oct 13, 2012, 12:35 AM UTC

ramidarigaz wrote: post #31

tarice wrote: post #25

Earlier quoted context omitted.

A orbit raising maneuver was always necessary to get the satellite to its target. Relevant sections: > "Orbcomm had planned on reaching an altitude of 466 miles above Earth..." > "Due to the engine shutdown, the Falcon 9 used slightly more fuel and oxygen to reach Dragon's intended 202 mile- (325-km) high orbit. Over the next 2.5 days, Dragon flew itself to the station's orbit 250 miles above Earth. It reached the $1…

Right. They were hoping the F9 upper stage would do that orbit raising for them (the non-risky version). The risky part was trying to do an orbit raising with the satellite's onboard fuel, which was the only option after the F9 lost an engine. The expected outcome (F9 upper stage doing the raising) was considered non-risky, and I'm sure that's the premise the insurance company was operating under when they agreed to…

No, the risky part was trying to raise the orbit using the F9 upper stage after it had burned more fuel than expected due to the failed engine.

Quoth the article:

> Falcon 9 had enough kerosene fuel left over to relight the engine, but the amount of liquid oxygen "was only enough to achieve a roughly 95 percent likelihood of completing the second burn, so Falcon 9 did not attempt a restart,"

I doubt many satellites have enough maneuvering fuel on-board to raise their orbit like that.

Re: Satellite burns up following SpaceX rocket glitch

#39

Post by meepmorp » Sat, Oct 13, 2012, 12:40 AM UTC

tsotha wrote: post #34

vl wrote: post #32

Earlier quoted context omitted.

It's unclear to me what is the risk to ISS. Secondary payload was on the much lower orbit, and even if it was on the same orbital plane, they could just slightly change orbit plane, and try to raise the obit with any chance of success entirely safe for ISS.

It's probably mostly a theoretical risk. On the other hand, I recall a flight to Mir that ended up slamming into the station. And NASA doesn't have any reason to accept a risk that doesn't benefit its operations.

> And NASA doesn't have any reason to accept a risk that doesn't benefit its operations.

Goodwill in the space community and helping to defray costs of future launches by making commercial launches more successful (and thus less expensive, if only for insurance purposes) seem like things that benefit their operations. Perhaps this is a naive opinion, though.

Re: Satellite burns up following SpaceX rocket glitch

#40

Post by mikeash » Sat, Oct 13, 2012, 12:41 AM UTC

tocomment wrote: post #29

I never understood why this company couldn't make do with the orbit spacex left it in?

No, orbit isn't orbit. Among many other considerations, the key problem here was that the initial orbit was low enough for atmospheric drag to be a factor, thus why it fell back to Earth after just a few days.