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Satellite burns up following SpaceX rocket glitch

reuters.com

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Re: Satellite burns up following SpaceX rocket glitch

#81

Post by mbenjaminsmith »

RockyMcNuts wrote: post #74
martinkallstrom wrote: post #5

It is perfectly clear that this is a story of safety margines adhered to in an admirably strict fashion; not allowing short term thinking rule over long term; and certainly not allowing marketing rule over engineering. This is how you move mountains.

Perfectly clear that PR best practices were adhered to in an admirably strict fashion - show beautiful pictures of apparent success on live video, bury the part where the satellite burns up until after hours on a Friday!

Apparently you know nothing about PR "best practices". No consultant worth their salt would have allowed SpaceX to handle the secondary mission failure they way they did. They made a series of classic and potentially disastrous mistakes. The best thing they could have done was address the issue head on with what information they had and then filled in further details as they were known.

To build credibility you have to admit failure. You can't just omit the bad news while focusing on the good news. You can't allow rumor and speculation to be your spokesperson. There's no way around the fact that an engine failure led to the failure of their secondary mission. Test platform or not, fully insured or not, an expensive piece of hardware became a shooting star. Someone didn't get what they paid for.

How it was handled was seriously amateurish. It made me cringe because I really want to see SpaceX (and Musk) succeed. Shit happens, but how you respond to that as an organization defines you for better or worse.

Re: Satellite burns up following SpaceX rocket glitch

#82

Post by SoftwareMaven »

meepmorp wrote: post #39
tsotha wrote: post #34

Earlier quoted context omitted.

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.

And that was why they accepted 99% instead of 99.9% or 99.99%.

Re: Satellite burns up following SpaceX rocket glitch

#83

Post by FSEA »

martinkallstrom wrote: post #5

It is perfectly clear that this is a story of safety margines adhered to in an admirably strict fashion; not allowing short term thinking rule over long term; and certainly not allowing marketing rule over engineering. This is how you move mountains.

Your post is marketing and PR.

Re: Satellite burns up following SpaceX rocket glitch

#84

Post by jordanthoms »

Is there an explanation somewhere (preferably with a diagram) of how this launch was supposed to work? I'm not sure where the satellite was attached, and how the upper stage was supposed to boost it - was it going to drop the dragon off at one orbit and then continue higher and release the satellite?

Re: Satellite burns up following SpaceX rocket glitch

#85

Post by vl »

danielweber wrote: post #65
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 wasn't a 95%/99% of the satellite making it; those were the chances that there wouldn't be an incident with the ISS if the upper stage activated. The Falcon 9 ended up in a slightly different position/velocity than was expected, and the primary mission (deliver to the ISS and don't dare run anything into it) took complete priority over the secondary mission of launching the other satellite into a high orbit.

Article says the opposite:

if there was not at least a 99 percent chance that the rocket had enough fuel to complete the burn

Re: Satellite burns up following SpaceX rocket glitch

#86

Post by ordinary »

aeontech wrote: post #78
[deleted] wrote: post #69

Earlier quoted context omitted.

[deleted]

You are mixing your terms I think. (2/4)^3 is the chances of the next launch also having a single engine failure. The chances of a single engine failing in a launch based on these four launches should be 2/36, two engines failed out of 36 fired total. So, assuming that a single engine failure does not increase failure chance of nearby engines (which is not true probably), and assuming past performance is indicator of…

> Based on current engine failure rate, that's (17/18)^9 + (1/18)^8 + C(9,2) * (1/18)^2 * (17/18)^7

I think the second part of that calculation is incorrect. I'm getting:

  P(0 engine fail) = (17/18)^9 ~= 0.5978
  P(1 engine fail) = (17/18)^8 * (1/18) * C(9,1) ~= 0.3165
  P(2 engine fail) = (17/18)^7 * (1/18)^2 * C(9,2) ~= 0.0745
Adding those together gives:

  P(
That's the same answer you came up with, so I guess you have the correct calculation written down somewhere. Moving to 3 or more engine fails then gives:

  P(>=3 engine fail) = 1 - P(

Re: Satellite burns up following SpaceX rocket glitch

#87

Post by dbaupp »

aeontech wrote: post #78
[deleted] wrote: post #69

Earlier quoted context omitted.

[deleted]

You are mixing your terms I think. (2/4)^3 is the chances of the next launch also having a single engine failure. The chances of a single engine failing in a launch based on these four launches should be 2/36, two engines failed out of 36 fired total. So, assuming that a single engine failure does not increase failure chance of nearby engines (which is not true probably), and assuming past performance is indicator of…

Not commenting on the correctness or otherwise of the rest, but 98.88 + 0.02 != 100. (You probably want 1.12% chance of triple or more failure.)

Re: Satellite burns up following SpaceX rocket glitch

#88

Post by sylvinus »

danielweber wrote: post #68
confluence wrote: post #36

> 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 astr…

The primary mission was a success. The secondary mission was a failure. $10 million probably covers Orbcomm's launch costs. SpaceX is awesome, but this isn't an unqualified win. There are groups out for SpaceX's head and they will try (unsuccessfully, I hope) to use this "engine incident" against them. SpaceX did not want this to happen at all.

They shure didn't want this to happen but they also demonstrated they were able to manage engine failure. That's worth something for the future.

Re: Satellite burns up following SpaceX rocket glitch

#89

Post by revelation »

Can someone clarify this for me? Why does the contract with NASA forbid them to restart the engine unless they have a 99% chance of completing a second burn?

Is the problem here that if you start a second burn and have to end it prematurely, you could end up in an orbit intersecting the ISS?

Re: Satellite burns up following SpaceX rocket glitch

#90

Post by ktizo »

Dylan16807 wrote: post #79
sp332 wrote: post #76

Earlier quoted context omitted.

A group of communications satellites have to be deployed in a synchronized way, to continuously cover the area they target. Changing the orbit of this satellite would mean changing the orbits of the other 16 satellites as well. Also I'm pretty sure you have to license a particular orbit ahead of time instead of just picking whatever is convenient at the moment.

Were they putting this into the exact same orbit as the others? I thought it was mostly a test sat. Who do you license orbits from?

Issac Newton got quite bored after becoming immortal and now has a little booth set up at the patent office. Don't take the piss out of his wig, otherwise you will get nowhere with him.
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