4 ms·

Intelsat 35e Mission [pdf]

28 points by janober 9y ago

thatcherc 9y ago
Interesting that nothing is said about why two scrubs occurred. SpaceX seems to have been forthcoming with details about anomalous flights in the past like Amos 6 and CRS-7, but I haven't found anything that gives an explanation for why the first two launch attempts didn't succeed.
- crush-n-spread 9y ago
  They were forthcoming in both Sunday and Monday's webcasts of the failed launch. In both cases, it was a data anomoly 10s from launch
  - ChuckMcM 9y ago
    Which is to say at t-10 seconds when its pretty simple and routine to scrub, they do a massive comparison of sensor data and system status versus expected data and expected status. If that fails for any reason they scrub. It takes them a while to go through all of the data to figure out what data caused the scrub and then a while longer to figure out what caused the data to be "wrong".
  - thatcherc 9y ago
    My question though is what was that data anomaly? Also was it the same thing both times? Just curious really.
- jonmagic 9y ago
  See https://www.youtube.com/watch?v=SPepP_1qr8g https://www.youtube.com/watch?v=SPepP_1qr8g for an explanation for Monday's scrub. Fairly certain Monday's webcast had an explanation for the previous attempt as well.
aphextron 9y ago
What is SpaceX's scrub rate in comparison with the rest of the industry? It seems they are never hesitant to make the call, which seems great in my (uninformed) opinion.
- deleted 9y ago
  [deleted]
- dangrossman 9y ago
  There's this 10-year-old infographic from the AP about NASA's space shuttle launches: http://i.imgur.com/HVJtlTR.jpg http://i.imgur.com/HVJtlTR.jpg The shuttle launched on its scheduled launch date only 40% of the time. 56.2% of the delays were due to technical reasons, not weather.
  - voltagex_ 9y ago
    How serious is a scrub, in terms of lost revenue and loss of "face"? I get that it's much less of a problem than losing a rocket/payload, but it must still be bad.
    - TaylorAlexander 9y ago
      Imagine you're paying $300m to put a satellite in to space (SpaceX nominally charges $60m for private customers, and satellites are often hundreds of millions of dollars). The satellite will be in service for 5-15 years. Imagine that, due to price (you save, I'm guessing, $40m or more) you choose a young rocket company that has experienced two serious failures that destroyed the payload. Imagine that company is very cautious and will happily abort any launch that looks odd. I imagine the caution is a positive aspect.
      - jgalt212 9y ago
        I don't think you came even close to answering the question.
ChuckMcM 9y ago
A possibly interesting question for someone at Spacex. At some point the Falcon9 heavy will be flying. And with it comes the ability to put a heavier mass into orbit, or to put what an F9 could put into orbit but could not recover the boosters from. So on a mission like this, if it "upgraded" to a Falcon9 heavy and all three boosters were recovered, then it seems the marginal cost difference would be the cost of fuel versus the cost of a booster. Since it has been asserted that the fuel cost is 'insignificant' compared to the cost of a booster, does the math pencil out? Of course there is a risk of losing all three boosters but in other transport industries spending additional fuel to save operational costs is often a good strategy. I'm wondering if that is being considered once F9H is qualified.
- Cogito 9y ago
  Not at SpaceX but read /r/spacex a lot. The general consensus from arm chair rocket scientists is that the expendable version of the F9 will eventually be phased out completely. The one place it may remain is for customers who want a brand new rocket and also have an unrecoverable mission profile. As long as the Falcon Heavy is reliable, and the three cores are reliably recovered, it makes sense to replace an F9 expendable launch with a heavy launch. That won't happen immediately, but if the progress goes along a similar trajectory as the F9 did it probably won't take too long before every F9 core is recovered. Worth noting as well - the Falcon Heavy is never referred to as F9, but rather as F27, as the number refers to the number of engines on the main stage.

28 points by janober 9y ago

Interesting that nothing is said about why two scrubs occurred. SpaceX seems to have been forthcoming with details about anomalous flights in the past like Amos 6 and CRS-7, but I haven't found anything that gives an explanation for why the first two launch attempts didn't succeed.

crush-n-spread 9y ago
They were forthcoming in both Sunday and Monday's webcasts of the failed launch. In both cases, it was a data anomoly 10s from launch
- ChuckMcM 9y ago
  Which is to say at t-10 seconds when its pretty simple and routine to scrub, they do a massive comparison of sensor data and system status versus expected data and expected status. If that fails for any reason they scrub. It takes them a while to go through all of the data to figure out what data caused the scrub and then a while longer to figure out what caused the data to be "wrong".
- thatcherc 9y ago
  My question though is what was that data anomaly? Also was it the same thing both times? Just curious really.
jonmagic 9y ago
See https://www.youtube.com/watch?v=SPepP_1qr8g https://www.youtube.com/watch?v=SPepP_1qr8g for an explanation for Monday's scrub. Fairly certain Monday's webcast had an explanation for the previous attempt as well.

aphextron 9y ago

What is SpaceX's scrub rate in comparison with the rest of the industry? It seems they are never hesitant to make the call, which seems great in my (uninformed) opinion.

deleted 9y ago
[deleted]
dangrossman 9y ago
There's this 10-year-old infographic from the AP about NASA's space shuttle launches: http://i.imgur.com/HVJtlTR.jpg http://i.imgur.com/HVJtlTR.jpg The shuttle launched on its scheduled launch date only 40% of the time. 56.2% of the delays were due to technical reasons, not weather.
- voltagex_ 9y ago
  How serious is a scrub, in terms of lost revenue and loss of "face"? I get that it's much less of a problem than losing a rocket/payload, but it must still be bad.
  - TaylorAlexander 9y ago
    Imagine you're paying $300m to put a satellite in to space (SpaceX nominally charges $60m for private customers, and satellites are often hundreds of millions of dollars). The satellite will be in service for 5-15 years. Imagine that, due to price (you save, I'm guessing, $40m or more) you choose a young rocket company that has experienced two serious failures that destroyed the payload. Imagine that company is very cautious and will happily abort any launch that looks odd. I imagine the caution is a positive aspect.
    - jgalt212 9y ago
      I don't think you came even close to answering the question.

ChuckMcM 9y ago

A possibly interesting question for someone at Spacex. At some point the Falcon9 heavy will be flying. And with it comes the ability to put a heavier mass into orbit, or to put what an F9 could put into orbit but could not recover the boosters from. So on a mission like this, if it "upgraded" to a Falcon9 heavy and all three boosters were recovered, then it seems the marginal cost difference would be the cost of fuel versus the cost of a booster. Since it has been asserted that the fuel cost is 'insignificant' compared to the cost of a booster, does the math pencil out? Of course there is a risk of losing all three boosters but in other transport industries spending additional fuel to save operational costs is often a good strategy. I'm wondering if that is being considered once F9H is qualified.

Cogito 9y ago
Not at SpaceX but read /r/spacex a lot. The general consensus from arm chair rocket scientists is that the expendable version of the F9 will eventually be phased out completely. The one place it may remain is for customers who want a brand new rocket and also have an unrecoverable mission profile. As long as the Falcon Heavy is reliable, and the three cores are reliably recovered, it makes sense to replace an F9 expendable launch with a heavy launch. That won't happen immediately, but if the progress goes along a similar trajectory as the F9 did it probably won't take too long before every F9 core is recovered. Worth noting as well - the Falcon Heavy is never referred to as F9, but rather as F27, as the number refers to the number of engines on the main stage.