SpaceX F9 : Starlink 5 (v1.0 L4) : Feb. 17, 2020 : Master Thread

[Comga]

I doubt it's ITAR. SpaceX tends to keep quiet during investigations. I suspect they don't have a clear cause and are investigating. It's a good thing to keep quiet until you have some facts.

Maybe it's something really embarrassing, such as leaving a pin out of one of the legs, then having two inspectors still sign off on it.  Something like that would put their whole safety culture and QA conscientiousness in question.

An oddly specific speculation.  Basis?

 - Ed Kyle

You may have missed the [sarc] font

Ed: Please tell us when you get the joke. 😁

[zubenelgenubi]

Moderator observation:
Lou's sarcasm re: Commercial Crew providers noted.   Further analysis of said sarcasm should move to the party thread.   Serious compare and contrast of safety cultures should adjourn to another, more appropriate thread.

[clongton]

An oddly specific speculation.  Basis?  - Ed Kyle

You may have missed the [sarc] font

There's a sarcasm font? Really? If so then it doesn't look any different that the normal font.
Sarcasm should be posted thus:
[sarc] <actual sarcasm> [/sarc]

[AnalogMan]

An oddly specific speculation.  Basis?  - Ed Kyle

You may have missed the [sarc] font

There's a sarcasm font? Really? If so then it doesn't look any different that the normal font.
Sarcasm should be posted thus:
[sarc] <actual sarcasm> [/sarc]

Ah, the trick to seeing the sarcasm font is to always read carefully between the lines.   

[SteveU]

Back to topic (sarc font too hard to read)

Based on OCISLY’s video the seas in LZ didn’t seem too rough, but, we are looking at a failed landing by a booster and two badly damaged fairing halfs from the same launch. Could there have been issues like sever upper level winds or sheer that could have affected all three? Caused the booster to use extra fuel or other consumables and also played havoc with the fairings or chutes?

(Out of curiosity- are they still using an open circuit for the grid-fin hydraulics?)

[ZachS09]

Back to topic (sarc font too hard to read)

Based on OCISLY’s video the seas at the Landing Zone didn’t seem too rough, but we are looking at a failed landing by a booster and two badly damaged fairing halves from the same launch. Could there have been issues like severe upper level winds or shear that could have affected all three? Caused the booster to use extra fuel or other consumables and also played havoc with the fairings or chutes?

(Out of curiosity- are they still using an open circuit for the grid-fin hydraulics?)

That's kind of plausible regarding the ULWs. Maybe that could be one of the reasons why the signal was lost during the entry burn. And I'm saying ONE of the reasons because the most frequently discussed reason was similar to what happens on the drone ship, but who knows? Maybe once SpaceX finds out what happened exactly, it could be a different reason none of us were expecting.

[LouScheffer]

Back to topic (sarc font too hard to read)

Based on OCISLY’s video the seas at the Landing Zone didn’t seem too rough, but we are looking at a failed landing by a booster and two badly damaged fairing halves from the same launch. Could there have been issues like severe upper level winds or shear that could have affected all three? Caused the booster to use extra fuel or other consumables and also played havoc with the fairings or chutes?

(Out of curiosity- are they still using an open circuit for the grid-fin hydraulics?)

That's kind of plausible regarding the ULWs. Maybe that could be one of the reasons why the signal was lost during the entry burn. And I'm saying ONE of the reasons because the most frequently discussed reason was similar to what happens on the drone ship, but who knows? Maybe once SpaceX finds out what happened exactly, it could be a different reason none of us were expecting.

Between the entry burn and the landing burn, the rocket is only guided by the grid fins, with a little help from the RCS.  So the entry burn should target the ship, assuming some model of the intervening winds.  If the winds were then different than predicted, the booster might not have enough cross range to reach the barge.  (And the winds were changing quite a bit day to day, prior to the launch.)

[Vettedrmr]

I can't see there being some kind of performance-related failure (didn't have enough cross-range); it wouldn't have landed as well as it did next to the landing site.  I'm thinking more like there was some kind of condition or detected failure condition that the booster determined not to translate to OCISLY.

[Lar]

I can't see there being some kind of performance-related failure (didn't have enough cross-range); it wouldn't have landed as well as it did next to the landing site.  I'm thinking more like there was some kind of condition or detected failure condition that the booster determined not to translate to OCISLY.

It's possible that the propellant reserves were on the ragged edge of acceptable for a safe landing so they waved off, but variance or luck made the splash gentle.

That would definitely be a performance related failure. Let's wait for the blooper reel.

[Johnnyhinbos]

Isn't it possible that the ASDS had parked at the wrong coordinates? Transposing digits on the fraction part of a lat or lon will still place the vessel in the wrong place... Asking for a friend.

[tgr9898]

I can't see there being some kind of performance-related failure (didn't have enough cross-range); it wouldn't have landed as well as it did next to the landing site.  I'm thinking more like there was some kind of condition or detected failure condition that the booster determined not to translate to OCISLY.

It's possible that the propellant reserves were on the ragged edge of acceptable for a safe landing so they waved off, but variance or luck made the splash gentle.

That would definitely be a performance related failure. Let's wait for the blooper reel.

Is there any other video than the SX live feed? Are we sure the splash was gentle and right next to OCISLY?

If the propellant for the landing burn was marginal, it's possible that the booster's "soft landing" wasn't quite soft enough and the splash we saw started farther from the barge than everyone thinks....

[Mandella]

Since we are speculating without any actual inside knowledge, here's mine:

It could have been a sensor failure. Nothing was wrong at all with the booster, but some sensor went out and the flight computer could not be sure the engine was functioning properly, or some other part. Excess of caution being the rule, the booster did not veer from the water to land on the booster.

[Comga]

Is there any other video than the SX live feed?
Are we sure the splash was gentle and right next to OCISLY?

If the propellant for the landing burn was marginal, it's possible that the booster's "soft landing" wasn't quite soft enough and the splash we saw started farther from the barge than everyone thinks....

Unless our own ClayJar paddled his kayak a hundred or so kilometers off shore to take pictures, any video would be from a SpaceX ship. I don’t recall seeing any remote images other than the Dragon parachute descent and the RIBs heading for the floating capsule. That is, no previous video of the landing from the tugs that I recall.
If SpaceX has it, they will release it in their own good time.
Maybe if Elon edits his blooper reel.

[AndrewRG10]

Is there any other video than the SX live feed? Are we sure the splash was gentle and right next to OCISLY?

If the propellant for the landing burn was marginal, it's possible that the booster's "soft landing" wasn't quite soft enough and the splash we saw started farther from the barge than everyone thinks....

No, what we see is all the live feed. Since SES-10 SpaceX stopped releasing the audio visual images from 3 different angles they have on the droneship. They don't seem too keen on releasing footage people want like that from BulgariaSat-1.

Back to topic (sarc font too hard to read)

Based on OCISLY’s video the seas in LZ didn’t seem too rough, but, we are looking at a failed landing by a booster and two badly damaged fairing halfs from the same launch. Could there have been issues like sever upper level winds or sheer that could have affected all three? Caused the booster to use extra fuel or other consumables and also played havoc with the fairings or chutes?

(Out of curiosity- are they still using an open circuit for the grid-fin hydraulics?)

No, no way wind can cause that damage to fairings. It's 99% likely that the parachute got caught in the net, the fairings detached and hit the deck. This is likely because there was a parachute in Ms Tree net.
And it's not like winds blew them off course and land 500metres away like on Iridium-6, they clearly were within 1 metre or so.

And grid fins use the closed circuit with valves to stop stalls. B1056 would've been one of the first new boosters to get the upgraded system. Open circuit hydraulics were a problem on CRS-5 but they didn't make them closed-circuit till quite after, they just chucked more fluid in.


Why did it fail then? We might not know for weeks months or years, SpaceX clearly is embarrassed and think it's bad PR to say why it failed, otherwise they would've shown footage and Elon done a quick Twitter Q&A as they've done for every other landing failure.

[TorenAltair]

Or they just don‘t know (yet) what failed during landing. For example, if it was a software bug that isn‘t reproduceable, they might be still evaluating the whole thing. Sometimes software behaves strange. And I can think of several more things, that might only give hints about the cause but no clear proof, so that might be the reason about the silence.

[AndrewRG10]

Or they just don‘t know (yet) what failed during landing. For example, if it was a software bug that isn‘t reproduceable, they might be still evaluating the whole thing. Sometimes software behaves strange. And I can think of several more things, that might only give hints about the cause but no clear proof, so that might be the reason about the silence.

Historically though Elon will acknowledge the failure within 1 hour, say they're working on getting video. Within 1 day they have video, release it and Elon says what they know. Heck on Jason-3 they were saying they thought it was a hard landing during the webcast even though that was wrong.
Elon hasn't even acknowledged or even liked a tweet acknowledging it failed.

[2megs]

Or.... they know internally, but this is the kind of information that normally comes out when one particular guy gets chatty on Twitter (rather than an official SpaceX release). Lately that guy has been all-in on Starship and maybe this just wasn't the top thing he was excited to tweet about. It doesn't need a more complicated explanation than that.

Perhaps someone can get in a question about it at the CRS presser next week.

[EspenU]

Isn't it possible that the ASDS had parked at the wrong coordinates? Transposing digits on the fraction part of a lat or lon will still place the vessel in the wrong place... Asking for a friend.

Yes, this has also been my guess for a while. The coordinates for the droneship are probably input manually. So the DPO for the droneship might have entered a wrong digit into the DP system, and there was no procedure for double checking the input value.

This is just speculation of course, but I can't see any other good reason for a miss when the landing was as smooth as it seemed to be.
It would also explain the radio silence from SpaceX regarding the issue. It's one thing to explain a failed landing with an unforeseen technical issue, but entering a wrong number might feel a bit embarrassing, and Elon doesn't feel a need to broadcast it.

[AndrewRG10]

Or.... they know internally, but this is the kind of information that normally comes out when one particular guy gets chatty on Twitter (rather than an official SpaceX release). Lately that guy has been all-in on Starship and maybe this just wasn't the top thing he was excited to tweet about. It doesn't need a more complicated explanation than that.

Perhaps someone can get in a question about it at the CRS presser next week.

Really hoping some certain YouTuber or some certain NSF reporter goes in and asks for the reason and also video. Video from onboard or different droneship camera is most interesting for me.

[StuffOfInterest]

Is there any other video than the SX live feed? Are we sure the splash was gentle and right next to OCISLY?

If the propellant for the landing burn was marginal, it's possible that the booster's "soft landing" wasn't quite soft enough and the splash we saw started farther from the barge than everyone thinks....

No, what we see is all the live feed. Since SES-10 SpaceX stopped releasing the audio visual images from 3 different angles they have on the droneship. They don't seem too keen on releasing footage people want like that from BulgariaSat-1.

Would be nice if they would release more of the 360 videos like this:



That is one of my favorites out there.  Really works nice on a cell phone when you can change viewing angle by just moving the phone.