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SpaceX first stage landing failed for Starlink-4 launch

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Re: SpaceX first stage landing failed for Starlink-4 launch

#11

Post by bo0tzz »

tomp wrote: post #9
bolasanibk wrote: post #4

SpaceX has made landing so routine that now failed landings are news.

I wonder if they're deliberate? Like if you're 100% you can land in "normal" circumstances, maybe try perturbing the parameters or input data a bit... to stress-test your algos, as if simulating wind, earthquake, different planet's gravity, different atmosphere, different rocket, engine failure...

Absolutely. Musk has openly shared that at spacex, failure is just a chance to learn. Successful landings don't teach you much, so the launch of an old core like this one (4 previous landings) is a good chance to experiment a bit.

Re: SpaceX first stage landing failed for Starlink-4 launch

#12

Post by DennisP »

cowmix wrote: post #10
tomp wrote: post #9

Earlier quoted context omitted.

I wonder if they're deliberate? Like if you're 100% you can land in "normal" circumstances, maybe try perturbing the parameters or input data a bit... to stress-test your algos, as if simulating wind, earthquake, different planet's gravity, different atmosphere, different rocket, engine failure...

Now that these are used to launch their own cargo (no not paid launches) I'm sure every loss hits them hard.

A failure on launch would hit them harder, but a failure landing the empty rocket costs the same as it always did, assuming they've got enough spare capacity to keep up the launch schedule.

Re: SpaceX first stage landing failed for Starlink-4 launch

#13

Post by baseballMan »

Shivetya wrote: post #3

well it would become noteworthy that their failures make news simply because they had taken the concept of recovering the first stage to the point of people just assuming it was how rocket launches are meant to be. I remember the first video of one successfully landing after launching and being wowed but when two landed together then it truly felt like science fiction had become reality

I remember everyone in my office stopped working for about 30 minutes to watch that dual rocket landing and being completely blown away.

Re: SpaceX first stage landing failed for Starlink-4 launch

#14

Post by clutchingstraws »

xt00 wrote: post #5

I believe they do a little horizontal kick just before landing when they validate things are look good. Potentially something wasn’t right and it just crashed into the ocean like 100 yards from the drone ship.. the good thing is that spaceX seems to learn from all of these issues and compensates, so will be interesting to here what happened.

This is accurate. More good examples of this passive-safety landing procedure in action were in the Heavy demo flight and the CRS-16 mission. The Heavy demo center core failed to relight two of the three engines needed for landing, and plunged right into the water off the side of the landing barge (https://youtu.be/A0FZIwabctw?t=72). CRS-16's booster had a hydraulic failure of the grid fins but still had engine and RCS control, so it was able to make a soft water splashdown at the last second (dramatic video from the booster's perspective is here: https://twitter.com/elonmusk/status/1070399755526656000).

Re: SpaceX first stage landing failed for Starlink-4 launch

#15

Post by phkahler »

tomp wrote: post #9
bolasanibk wrote: post #4

SpaceX has made landing so routine that now failed landings are news.

I wonder if they're deliberate? Like if you're 100% you can land in "normal" circumstances, maybe try perturbing the parameters or input data a bit... to stress-test your algos, as if simulating wind, earthquake, different planet's gravity, different atmosphere, different rocket, engine failure...

I thought this launch was harder than the previous starlink missions. It's not like going to GTO but starlink payloads are really heavy and they mentioned the drone ship would be further down range due to a different orbit this time.

It will be good to hear what the problem was.

Re: SpaceX first stage landing failed for Starlink-4 launch

#17

Post by jessriedel »

dtparr wrote: post #7
jessriedel wrote: post #2

Here's a list that includes all their landing attempts: https://en.wikipedia.org/wiki/List_of_Falcon_9_and_Falcon_He... After their first successful drone-ship landing in April 2016, they had two failures of Falcon 9 in June 2016 and Dec 2018, two failures (of core only) on Falcon Heavy in Feb 2018 and June 2019, and 47 successful landing.

I believe it's 48 successful landings after the 1st as they kept mentioning today would be the 50th successful core to land. (Which counts each booster separately, including the FH side cores, but you must have been doing that too to get to 48 since the first)

I'm giving the number of successful landing after the first successful drone-ship landing, which doesn't include the first successful pad landing. (This seemed a more fair way to count because drone-ship landing are harder; if you start counting after the first successful pad landing you include two failed drone ship landing which should be considered still total experiments.)

Re: SpaceX first stage landing failed for Starlink-4 launch

#18

Post by aguyfromnb »

bo0tzz wrote: post #11
tomp wrote: post #9

Earlier quoted context omitted.

I wonder if they're deliberate? Like if you're 100% you can land in "normal" circumstances, maybe try perturbing the parameters or input data a bit... to stress-test your algos, as if simulating wind, earthquake, different planet's gravity, different atmosphere, different rocket, engine failure...

Absolutely. Musk has openly shared that at spacex, failure is just a chance to learn. Successful landings don't teach you much, so the launch of an old core like this one (4 previous landings) is a good chance to experiment a bit.

>Absolutely.

There is no chance they are deliberately crashing rockets because landing them is too easy. That's lunacy.

Re: SpaceX first stage landing failed for Starlink-4 launch

#19

Post by SquareWheel »

aguyfromnb wrote: post #18
bo0tzz wrote: post #11

Earlier quoted context omitted.

Absolutely. Musk has openly shared that at spacex, failure is just a chance to learn. Successful landings don't teach you much, so the launch of an old core like this one (4 previous landings) is a good chance to experiment a bit.

> Absolutely. There is no chance they are deliberately crashing rockets because landing them is too easy. That's lunacy.

Agreed. They do stress test old cores, but they make it clear that it's an intentional test before they do so. They don't shake up the parameters on a whim just because they've had a good stretch.
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