Author Topic: SpaceX Falcon Heavy : Arabsat 6A : LC-39A : April 11, 2019 - DISCUSSION (Read 308849 times)

Celestar · « **Reply #600 on:** 04/15/2019 01:59 pm »

Hi guys,

Is there a reason why the fairing jettison on this flight higher and faster than what seems to be norm? Is there some technical reason for waiting until after stage sep? Or could they theoretically do that earlier, not that it yields a whole lot of performance...

Thanks,
Celestar

Nomadd · « **Reply #601 on:** 04/15/2019 02:09 pm »

Quote from: Celestar on 04/15/2019 01:59 pm

Hi guys,

Is there a reason why the fairing jettison on this flight higher and faster than what seems to be norm? Is there some technical reason for waiting until after stage sep? Or could they theoretically do that earlier, not that it yields a whole lot of performance...

Thanks,
Celestar

Realizing I'll probably be shortly corrected, I think it might have been jettisoned higher because it was faster. They jettison when dynamic pressure goes below a certain point, so the faster you're going, the higher you'll have to be.

pb2000 · « **Reply #602 on:** 04/15/2019 02:22 pm »

The fairing is probably also rated to be deployed at a specific acceleration, which might be too high under first stage power.

RocketLover0119 · « **Reply #603 on:** 04/15/2019 08:01 pm »

Im hosting a center core recovery thread on Reddit, and someone posted this:

"I’ve heard rumors that a pilot operating a research airplane over the Atlantic at “relatively low altitude” has seen the center core “laying flat” on the droneship’s deck."

This IS from Reddit, so I refuse to believe it, but part of me is nervous......

emerrill · « **Reply #604 on:** 04/15/2019 08:11 pm »

EverydayAstronaut is reporting the same

https://twitter.com/Erdayastronaut/status/1117880400175435776

Doesn't make it true, but still a datapoint.

Wolfram66 · « **Reply #605 on:** 04/15/2019 08:11 pm »

Quote from: RocketLover0119 on 04/15/2019 08:01 pm

Im hosting a center core recovery thread on Reddit, and someone posted this:

"I’ve heard rumors that a pilot operating a research airplane over the Atlantic at “relatively low altitude” has seen the center core “laying flat” on the droneship’s deck."

This IS from Reddit, so I refuse to believe it, but part of me is nervous......

Tweet from Everyday Astronaut says that due to rough seas, Center core toppled over... with OctoGrabber attached or prior to securing to the Deck ... IDK

envy887 · « **Reply #606 on:** 04/15/2019 08:17 pm »

Must have been some really rough seas. They weren't able to tie down the Thaicom-8 booster, but that made it to port OK despite sliding all over the barge deck.

Nomadd · « **Reply #607 on:** 04/15/2019 08:34 pm »

Does the FH core have the four points the Octograbber uses or only two?

Flying Beaver · « **Reply #608 on:** 04/15/2019 08:36 pm »

Quote from: ZachS09 on 04/14/2019 02:27 am

My best hope is that the center core does not fall overboard.

This post hasn't aged well.

kevinof · « **Reply #609 on:** 04/15/2019 08:43 pm »

If it's happened then I'm not surprised - figured it would at some point. North Atlantic is ok Summer 80% of the time, and 20% it's the wrong place to be. In Winter, it's the other way around.

abaddon · « **Reply #610 on:** 04/15/2019 08:47 pm »

Well, that is disappointing*, on the other hand if it is still on the ASDS, at least they will get to look at the stage and I bet there's still a lot of value to be had in evaluating how it performed. Obviously it's better to get the core back intact...

* Also this likely means no Bingo winner, which is only a little less important.

whitelancer64 · « **Reply #611 on:** 04/15/2019 08:50 pm »

Quote from: emerrill on 04/15/2019 08:11 pm

EverydayAstronaut is reporting the same

https://twitter.com/Erdayastronaut/status/1117880400175435776

Doesn't make it true, but still a datapoint.

That twitter post has been deleted.

king1999 · « **Reply #612 on:** 04/15/2019 09:09 pm »

Quote from: whitelancer64 on 04/15/2019 08:50 pm

Quote from: emerrill on 04/15/2019 08:11 pm
EverydayAstronaut is reporting the same

https://twitter.com/Erdayastronaut/status/1117880400175435776

Doesn't make it true, but still a datapoint.

That twitter post has been deleted.

“Over the weekend, due to rough sea conditions, SpaceX’s recovery team was unable to secure the center core booster for its return trip to Port Canaveral,” SpaceX said in a statement to The Verge. “As conditions worsened with eight to ten foot swells, the booster began to shift and ultimately was unable to remain upright. While we had hoped to bring the booster back intact, the safety of our team always takes precedence. We do not expect future missions to be impacted.”

https://www.theverge.com/2019/4/15/18311945/spacex-falcon-heavy-center-core-drone-ship-rough-ocean

gongora · « **Reply #613 on:** 04/15/2019 09:18 pm »

Quote from: Flying Beaver on 04/15/2019 08:36 pm

Quote from: ZachS09 on 04/14/2019 02:27 am
My best hope is that the center core does not fall overboard.

This post hasn't aged well.

You and I seem to have different understandings of the phrase "hasn't aged well'. Something that turned out to be applicable to the situation has indeed aged well.

OxCartMark · « **Reply #614 on:** 04/15/2019 09:22 pm »

Probably true but I'm gonna wait to see the carcass before I fully check this one off as lost. We've seen some really heavy seas and even a stage that was actively dancing about the deck and having its legs stopping up against the toe railing and they stood upright. On the other hand the CG should be higher because of the added structural reinforcement along its whole length but hmm, maybe it did, maybe it didn't.

ZachS09 · « **Reply #615 on:** 04/15/2019 09:37 pm »

I can't believe I accidentally predicted the center core's fate.

Here I go again with my Nostradamus personality.

whitelancer64 · « **Reply #616 on:** 04/15/2019 09:42 pm »

Best case scenario, it "walked" to one edge and tipped over and is laying across the ASDS. Keeping in mind, it is about as tall as a 14 story building. Things that tall do not tip over and not get damaged, so most likely, some of the structure is toast, just like 1050 on CRS-16, and probably has suffered internal structural damage that won't be easily visible from the outside.

Fortunately, SpaceX will be able to salvage as much of its components as it possibly can, get some engineering inspection on the engine section, and hopefully will have saved all 4 grid fins (those things are spendy).

Unfortunately for us, SpaceX will probably cover it with a tarp before it comes into port.

Worst case scenario, (presuming the report that a pilot saw it laying on the deck is accurate) it fell over, broke apart, and some of it is now at the bottom of the Atlantic ocean.

spacenut · « **Reply #617 on:** 04/15/2019 10:05 pm »

Can they remedy this in the future, by putting a crew on board and using cable of something to strap it down?

Even with the toppling, was any portion of the booster able to be salvaged, or towed in? Or, did it sink?

Lars-J · « **Reply #618 on:** 04/15/2019 10:07 pm »

Quote from: Nomadd on 04/15/2019 08:34 pm

Does the FH core have the four points the Octograbber uses or only two?

Correct, only two of the "normal" attachment/hold-down points. The other two are modified to hold on to the side booster through a different mechanism.

The best solution for the future is probably to modify the octagrabber to be able to grab the FH center core by switching out some grabber hardware.

Quote from: spacenut on 04/15/2019 10:05 pm

Can they remedy this in the future, by putting a crew on board and using cable of something to strap it down?

That's not a real remedy, that just adds a lot of risk in bad weather. The octagrabber is the superior solution.

whitelancer64 · « **Reply #619 on:** 04/15/2019 10:21 pm »

Quote from: spacenut on 04/15/2019 10:05 pm

Can they remedy this in the future, by putting a crew on board and using cable of something to strap it down?

That's what they do already. The rough sea state prevented crew from boarding the ASDS.

Quote

Even with the toppling, was any portion of the booster able to be salvaged, or towed in? Or, did it sink?

Not known at this time. There is a claim on Reddit that a low-flying pilot saw the booster laying on the deck of the ASDS. Unconfirmed.