71–80 of 111 posts
> 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…
> 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…
Unlikely they got screwed over. Insurance money doesn't come out of thin air. Insurance companies charge a premium for coverage and that premium usually goes up after a coverage event to make up for the increased risk. Insurance companies very rarely get screwed over.
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…
Well yes - it's frankly impressive enough that it's possible to get insurance to cover putting your satellite on one of SpaceX's rockets. Speaks well to the future of private space travel that there are institutions willing to take that bet, at a price commercial customers of SpaceX are evidently willing to pay.
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.
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.
It should; all of the material quotes in this article came from a SpaceX public relations agent and not from independent space analysts. Not exactly objective. The only quote from Orbicomm is practically a tautology.
Simple probability then gives a failure rate of 3%. I have not attempted the Bayesian analysis.
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.
On the other hand it doesn't explain why they didn't look at another orbit that they did have enough fuel for. Was this a decision that had to be made immediately?
Earlier quoted context omitted.
It should; all of the material quotes in this article came from a SpaceX public relations agent and not from independent space analysts. Not exactly objective. The only quote from Orbicomm is practically a tautology.
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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 future performance, and discounting all the test fires that they have done with the rocket, the formula should look more like the following:
Chances of any given 3 engines failing is the inverse of the chances of at least two engines failing at the same time.
Chances of at least two engines failing equals no engines failing + 1 engine failing + 2 engines failing
Based on current engine failure rate, that's (17/18)^9 + (1/18)^8 + C(9,2) * (1/18)^2 * (17/18)^7
where C(9,2) = 9!/(2! 7!) = 36
So that looks more like 98.88% chance of two or fewer engines failing, the converse of which is about 0.02% chance of a triple or more failure.
(math is not my strong suit, please correct me if I'm wrong, but #math on IRC thought this looked correct).
Earlier quoted context omitted.
On the other hand it doesn't explain why they didn't look at another orbit that they did have enough fuel for. Was this a decision that had to be made immediately?
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.
Who do you license orbits from?
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.
On the other hand it doesn't explain why they didn't look at another orbit that they did have enough fuel for. Was this a decision that had to be made immediately?