Author Topic: SpaceX Falcon 9 : GovSat-1 (SES-16) : Jan 31. 2018 - Discussion  (Read 207784 times)

Online envy887

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Why no boom? Haven't they always gone boom, when they hit the water?

So much has to go right ... for it not to go boom ...


You need to go back to this flight and water landing videos:

http://forum.nasaspaceflight.com/index.php?topic=35410.msg1243170#msg1243170
Just read the entire thread. Nothing there.

For it not to go boom, you have to safe the booster before it falls over. Can think of a hundred ways things can go wrong.

Wonder if they've sped up "safing" after landing a lot, and/or expend propellant more completely (like with a 3-engine terminal burn). Then all you might have to wait for is vent pressurant, inhibit FTS, and spool down the turbos as the long lead items.
I thought at least one previous landing survived hitting the water, but broke up quickly due to heavy waves. So, not go boom.

Offline ValmirGP

Better they hurry with some choppers with scuba divers and inflatable buoys if they are serious about getting it back, I think.

I dont know the exact landing position but I am sure it is borderline for rotary aircraft carrying and significant load.

A Westland Sea King HAS Mk.5 helicopter has a range of 741mi. A Sikorsky S-61R helicopter, 779mi. Last that i saw on the threads, the downrange was 327 km. More than enough, I think.

Online Prettz

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So to survive tipping over, does it have to be pressurized, or does it have to be unpressurized?

Offline Razvan

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This is a clear mission failure! The booster was to be thrown away and not towed back.  ???
In case they manage to get enough missions in the future they'll need another drone ship.
Why not a carrier (one that is going to be scraped). They can land the booster, one by one and lower them under the deck, refurbish, refuel and hop'em up to LZ.

Offline pb2000

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Another amazing, unprecedented sight.  Now they'll have to deal with this, because they can't just leave it floating.  I can't see how they can get it back into port, though.  I doubt the Port would even let them try. 

 - Ed Kyle
That's probably what people would have thought 10 years ago about a landed rocket on a barge, yet here we are.
Launches attended: Worldview-4 (Atlas V 401), Iridium NEXT Flight 1 (Falcon 9 FT), PAZ+Starlink (Falcon 9 FT), Arabsat-6A (Falcon Heavy)
Pilgrimaged to: Boca Chica (09/19 & 01/22)

Offline Kabloona

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Another amazing, unprecedented sight.  Now they'll have to deal with this, because they can't just leave it floating.  I can't see how they can get it back into port, though.  I doubt the Port would even let them try. 

 - Ed Kyle

It does look like a case of the dog who caught the bus. But they probably have three days or so of towing before reaching port to figure it out, if the stage stays afloat that long.

Offline lrk

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Another amazing, unprecedented sight.  Now they'll have to deal with this, because they can't just leave it floating.  I can't see how they can get it back into port, though.  I doubt the Port would even let them try. 

Remember, the original plan when they were testing water landings (before they had the droneship) was to tow them back, but none survived the tip-over event.  So they must have had some sort of plan at the time. 
« Last Edit: 02/01/2018 02:16 am by lrk »

Online aero

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Nosferocket 👻
Looks to me like it is much blacker than the other recovered stages. Maybe it's just the lighting.
Retired, working interesting problems

Offline Kabloona

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I would guess they have thought about how to tow it or at least sink it since they've tried a few soft splashdowns. In this case they also have a deadline with the next launch coming up. It would be ironic if this stage is expended (scuttled) due to FH even though the original reason for splashing it was to protect the droneship rather than FH schedule conflicts...  :P

This is one of the ships.  They should be able to chain it to the back of the boat and tow it in much quicker than the ASDS moves with a booster on top.  They could also have the other ship out there join this one to help with the tow.  I would think that recovering this floating booster would become a high priority so they can see what damage is caused by an ocean landing and then being in the ocean.  That would be useful data for SpaceX to have.

Not really.  Towing is going to damage it

Do you have any evidence for your claim?  Anything other than an argument from authority?

Obviously none of us has evidence, only best guesses. But it's probably a safe bet the stage wasn't designed to be towed, semi-submerged in seawater, with legs extended.

One thing I wonder about is the drag on the submerged legs. The load path of the legs to the body was designed for strength in compression at landing. But in this case there could be tremendous tension on the leg struts and at the strut attach points to the stage. Does one of those attach points fatigue or pull out, breaching the tank and sinking the stage? Or do the struts or fittings just break at the weakest point under tension? Or is it all strong enough to survive days of being dragged through water? Anybody's guess.

« Last Edit: 02/01/2018 02:32 am by Kabloona »

Offline Grandpa to Two

 ;D Here’s a suggestion sink it close to shore as a artificial reef. Aircraft carriers, ships, so why not a first stage Falcon 9? Flood the bottom tank first so it sits on the sea bed upright. How cool would that be? A divers paradise and useful for marine life.
"All truths are easy to understand once they are discovered; the point is to discover them" Galileo Galilei

Offline Oberon_Command

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I would guess they have thought about how to tow it or at least sink it since they've tried a few soft splashdowns. In this case they also have a deadline with the next launch coming up. It would be ironic if this stage is expended (scuttled) due to FH even though the original reason for splashing it was to protect the droneship rather than FH schedule conflicts...  :P

This is one of the ships.  They should be able to chain it to the back of the boat and tow it in much quicker than the ASDS moves with a booster on top.  They could also have the other ship out there join this one to help with the tow.  I would think that recovering this floating booster would become a high priority so they can see what damage is caused by an ocean landing and then being in the ocean.  That would be useful data for SpaceX to have.

Not really.  Towing is going to damage it

Do you have any evidence for your claim?  Anything other than an argument from authority?

Obviously none of us has evidence, only best guesses. But it's probably a safe bet the stage wasn't designed to be towed, semi-submerged in seawater, with legs extended.

One thing I wonder about is the drag on the submerged legs. The load path of the legs to the body was designed for strength in compression at landing. But in this case there could be tremendous tension on the leg struts and at the strut attach points to the stage. Does one of those attach points fatigue or pull out, breaching the tank and sinking the stage? Or do the struts or fittings just break at the weakest point under tension? Or is it all strong enough to survive days of being dragged through water? Anybody's guess.

Maybe they'll tow it from the octaweb?

Online Galactic Penguin SST

I wonder if temporarily leasing a barge with crane to pull the rocket stage out of water might be the best solution - assuming of course that such a barge/ship and team can be mobilized in a day or two.
Astronomy & spaceflight geek penguin. In a relationship w/ Space Shuttle Discovery. Current Priority: Chasing the Chinese Spaceflight Wonder Egg & A Certain Chinese Mars Rover

Offline Kabloona

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Quote
Maybe they'll tow it from the octaweb?

Maybe, but the aft end is mostly submerged, and the forward end is readily accessible and already designed with attach points for lifting ops, so a forward end tow would be my guess. Also, the way the stage is pitched in the water, a tow from the front has better hydrodynamics.

Offline kerrycockram

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This is a clear mission failure! The booster was to be thrown away and not towed back.  ???
In case they manage to get enough missions in the future they'll need another drone ship.
Why not a carrier (one that is going to be scraped). They can land the booster, one by one and lower them under the deck, refurbish, refuel and hop'em up to LZ.

If you're going to go through the trouble of procuring a carrier (I assume you meant aircraft carrier), why not just launch from the flight deck too? The logistics are similar to the usual kind of aircraft carrier. You need a log train to bring in fuel and new ordinance payloads, remove waste, and swap personnel out.

Did we just build a space navy?

Offline AUricle

We all know about the floating plastic garbage island swirling about in the Pacific, right?

Imagine a similar thing in the Atlantic....except that instead of plastic bottles, it's Falcon 9 cores ::)

Offline e of pi

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Congratulations to SpaceX, to OrbATK, to Luxembourg and SES, and to all the team who made today possible! We will truly always remember the day they almost----expended booster 1032! Amazing show, keep it rolling!

Online Comga

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Someone posted a picture of both Falcon 9 and FH on the pads. I had an old picture saved that I combined with the new one. These aren't my pictures - I just put them together.

The double shuttle picture was obviously a photoshop job. Not much meaning to compare these two pictures.

That is wrong

Jim waxing eloquent
3 words instead of 1
 ;)
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Online toren

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I wonder if temporarily leasing a barge with crane to pull the rocket stage out of water might be the best solution - assuming of course that such a barge/ship and team can be mobilized in a day or two.

Move the Port Canaveral crawler crane onto OCISLY with center of gravity a bit offset.  Tow it out to meet the GO sisters and B1032.  Tie onto the booster lift point, hoist away - with care.  Lower legs to ASDS deck to stop it swinging.  Tow OCISLY back into port, crawl crane back onto dockside, carrying booster.  OCISLY back to sea just in time for FH.

Offline curtquarquesso

Another amazing, unprecedented sight.  Now they'll have to deal with this, because they can't just leave it floating.  I can't see how they can get it back into port, though.  I doubt the Port would even let them try. 

Remember, the original plan when they were testing water landings (before they had the droneship) was to tow them back, but none survived the tip-over event.  So they must have had some sort of plan at the time.

Was it ever? Correct me if I'm wrong, but liquid propellant-fed engines and seawater don't mix terribly well...

Offline Kabloona

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I wonder if temporarily leasing a barge with crane to pull the rocket stage out of water might be the best solution - assuming of course that such a barge/ship and team can be mobilized in a day or two.

Move the Port Canaveral crawler crane onto OCISLY with center of gravity a bit offset.  Tow it out to meet the GO sisters and B1032.  Tie onto the booster lift point, hoist away - with care.  Lower legs to ASDS deck to stop it swinging.  Tow OCISLY back into port, crawl crane back onto dockside, carrying booster.  OCISLY back to sea just in time for FH.

Interesting idea, but OCISLY probably has to leave port Saturday for FH and I don't think there's enough time for OCISLY to get involved. They'll want to prioritize catching the FH core over salvaging this one.

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