SpaceX Falcon 9 : GovSat-1 (SES-16) : Jan 31. 2018 - Discussion

[vanoord]

Even if there’s no specific reason for bringing the stage back to inspect it, there may be things found on inspection that nobody was looking for or expected. That might - or might not - be valuable.

One benefit *could* be to see how immersion affects the vehicle from a point of view of potential recovery of upper stages into the ocean (landing legs not required).

[CyndyC]

Even if there’s no specific reason for bringing the stage back to inspect it, there may be things found on inspection that nobody was looking for or expected. That might - or might not - be valuable.

One benefit *could* be to see how immersion affects the vehicle from a point of view of potential recovery of upper stages into the ocean (landing legs not required).

Dragons have been recovered and reused that way, so why not the stages. At a recent pre-mission press conference we were told SpaceX learned they needed to make the Dragon more water tight, so they did.

[CyndyC]

Won't the stage still be moderately pressurized, to the point that if something happened divers next to it would be killed? Or do the tanks actually get vented to atmospheric?

Also what do they do, when they 'safe' the booster? How much 'safe-ing' were they able to do on this booster?

Found one of the first NSF articles about the ASDS dated June 18, 2015 with the following:

Hans Koenigsmann, SpaceX’s Vice President for Mission Assurance, said in a press conference before the CRS-5 mission that it would take about one to two hours after a landing for the crew to safe the stage remotely before boarding the drone ship. Remote-controlled safing activities would likely include venting pressurized helium from the fuel tank and venting residual LOX.
https://www.nasaspaceflight.com/2015/06/spacex-augments-upgrades-drone-ship-armada/

[speedevil]

Hans Koenigsmann, SpaceX’s Vice President for Mission Assurance, said in a press conference before the CRS-5 mission that it would take about one to two hours after a landing for the crew to safe the stage remotely before boarding the drone ship. Remote-controlled safing activities would likely include venting pressurized helium from the fuel tank and venting residual LOX.
https://www.nasaspaceflight.com/2015/06/spacex-augments-upgrades-drone-ship-armada/

Which works well if the stage has power, and the antennas are in line of sight and not underwater.

[Jim]

Even if there’s no specific reason for bringing the stage back to inspect it, there may be things found on inspection that nobody was looking for or expected. That might - or might not - be valuable.

One benefit *could* be to see how immersion affects the vehicle from a point of view of potential recovery of upper stages into the ocean (landing legs not required).

Dragons have been recovered and reused that way, so why not the stages. At a recent pre-mission press conference we were told SpaceX learned they needed to make the Dragon more water tight, so they did.

Because Dragons are designed for it and stages are designed for dry landings.  Stages have many unsealed compartments that are purged pre launch.  These compartment can't be made watertight

[CyndyC]

Even if there’s no specific reason for bringing the stage back to inspect it, there may be things found on inspection that nobody was looking for or expected. That might - or might not - be valuable.

One benefit *could* be to see how immersion affects the vehicle from a point of view of potential recovery of upper stages into the ocean (landing legs not required).

Dragons have been recovered and reused that way, so why not the stages. At a recent pre-mission press conference we were told SpaceX learned they needed to make the Dragon more water tight, so they did.

Because Dragons are designed for it and stages are designed for dry landings.  Stages have many unsealed compartments that are purged pre launch.  These compartment can't be made watertight

Well, ok, but you know SpaceX. Right now I have about a $50 cover at the top of a 1938 chimney that can be opened from the inside with an extra long chain to let smoke out, and can be closed from the inside with the same chain to keep rain water from coming in, and it does a really good job of both.

Edit to add most people here are probably familiar with "backflow valves" too, which prevent hard running water and its pressure from flowing back into the system when the water is shut off - similar mechanism might be used to purge whatever underwater and close up before water has a chance to get in.

[Kansan52]

Is it reasonable to assume they had a vessel there to capture telemetry and video of the water landing? They did post a picture of the first stage floating quickly after the ditching. The major information of such a landing they likely already have.

[Lar]

They should have kept the original Marmac 300. You didn't have to worry about lifting loads onto it's deck. It could go to them.
http://www.dredgemag.com/March-April-2003/Titan-Lifts-4000-ton-Wreck/

I thought all the Marmacs could do that? If not maybe the rental was less for the others... oops.

Yet more images from SpaceX

and yet, not the ones we really want! (they are gorgeous but I'm jaded)

[Freddedonna]

Seems to me like dragging the booster and somehow getting it to port/ground might take just as long or longer than just towing the ASDS would have taken under more normal circumstances, which was apparently already too much.
Do we have any idea if they have time to get back to port to grab the ASDS and head out for the FH launch?

[Kabloona]

Do we have any idea if they have time to get back to port to grab the ASDS and head out for the FH launch?

The ASDS is towed by a tug, this time probably "Hawk," not by GO Quest now towing the booster. So those events are independent.

The question is, will GO Quest get in and back out in time for FH. Quest has a faster top speed than the ASDS under tow, so as long she gets back out of port by late Sunday/early Monday, they'll be OK, though that may be cutting it close.

[Lar]

Seems to me like dragging the booster and somehow getting it to port/ground might take just as long or longer than just towing the ASDS would have taken under more normal circumstances, which was apparently already too much.
Do we have any idea if they have time to get back to port to grab the ASDS and head out for the FH launch?

A tow can be handed off in mid ocean so the Go Twins could head to their stations for the FH launch. But once you start using the ASDS you are committed to returning all the way and unloading and then going back out.. .so no, not the same timeframe.

THAT said, taking the ASDS out is done with tugs, not the Go Twins. BUT once out there, then what? Unless you brought a big crane with you, it doesn't do you much good.

[Johnnyhinbos]

They routinely haul boosters across the country somewhat pressurized, although I'm not sure to what level.  So a pressurized booster can't be that dangerous.

This booster has a lot of liquids and gases (and explosives) that wouldn't be in the boosters getting trucked around the country.

That's interesting. The transport trailers have devices that I beleive keep the stage tanks partially pressurised with inert gas (nitrogen or atmosphere?) so no liquids or gasses but I always assumed that the plastic explosive zipcord was put on in Hatwthorne, not at the launch pad... so it WOULD have explosives on it during transport. Wrong?

Also what do they do, when they 'safe' the booster? How much 'safe-ing' were they able to do on this booster?

Typically safing (and arming) is handled by a purpose build device that provides a physical connection via mechanical interface between the detcord and detonator.

Here’s an example:

 http://www.eba-d.com/products/electro-mechanical-safe-arm-sa-device/

EDIT: I’m just referring to the safing of the FTS system.

[John Alan]

Seems to me like dragging the booster and somehow getting it to port/ground might take just as long or longer than just towing the ASDS would have taken under more normal circumstances, which was apparently already too much.
Do we have any idea if they have time to get back to port to grab the ASDS and head out for the FH launch?

It's thought by myself and others here that the seagoing tugboat HAWK will be taking OCISLY (ASDS) out to sea in about 24 hours from now... For the FH launch attempt next Tuesday...
https://www.marinetraffic.com/en/ais/details/ships/shipid:430027/mmsi:366943250/imo:9103295/vessel:HAWK
The GO boats can cruise MUCH faster... if one needs to run in to get something and run back out...
ALSO... they have in the past, run to ports in the Bahamas for supplies or to get people on/off...
My guess is GO Quest will mind the booster for now and Go Searcher will take over later this weekend...
GO Quest will meet HAWK and OCISLY at the 215 mile planned point late Monday and make this work out...
GO Searcher will likely not be on fairing duty for FH... is my opinion (assuming B1032 stays afloat)...

Past that... and assuming the stage is still afloat come Wednesday or so...
Some kind of "take a hired crane barge out 25+ miles and fish the stage out onto a different ship" kind of operation is at least possible...

[Exastro]

I may have missed a post that made this point:


Plan A for recovering F9s was parachuting them into the ocean.  SX must have had detailed plans and hardware for retrieving them, no?  It's possible some of that capability was lost in the series of F9 upgrades, though.

[MechE31]

They routinely haul boosters across the country somewhat pressurized, although I'm not sure to what level.  So a pressurized booster can't be that dangerous.

This booster has a lot of liquids and gases (and explosives) that wouldn't be in the boosters getting trucked around the country.

That's interesting. The transport trailers have devices that I beleive keep the stage tanks partially pressurised with inert gas (nitrogen or atmosphere?) so no liquids or gases but I always assumed that the plastic explosive zipcord was put on in Hatwthorne[1], not at the launch pad... so it WOULD have explosives on it during transport. Wrong?

1 - and stayed on forever, across reuses, even?

All actual explosives are installed at the launch site, including the det cord, shape charges and initiators.

[envy887]

Hans Koenigsmann, SpaceX’s Vice President for Mission Assurance, said in a press conference before the CRS-5 mission that it would take about one to two hours after a landing for the crew to safe the stage remotely before boarding the drone ship. Remote-controlled safing activities would likely include venting pressurized helium from the fuel tank and venting residual LOX.
https://www.nasaspaceflight.com/2015/06/spacex-augments-upgrades-drone-ship-armada/

Which works well if the stage has power, and the antennas are in line of sight and not underwater.

I'm pretty sure Hans meant autonomously, not literally "remote controlled". I highly doubt they would have a human in the loop instead of having the stage pre-programmed to safe itself. If true, the stage should should vent everything as soon as it confirms altitude and velocity are zeroed.

[CyndyC]

Going by the cadence of the callouts from burn to legs to splashdown, I'm going with the 3 engine suicide burn.  Have they ever landed one of those, yet?  I remember SES-9 punching a nice hole in OCISLY when they tried it then.

A couple of different people answered Ronin's inquiry to the negative, and one thought there was no more than a 3-1 burn that succeeded, and I didn't see anyone disagree with those answers.

When I was searching for the old ASDS article, I came across some headlines with part of a paragraph showing, "Fresh from its unique three engine landing success, the Falcon 9 first stage (F9-0024-S1) has arrived back to the Florida coast from where it successfully launched the JCSAT-14 satellite." That article was by Chris Bergin in May 2016 covering the return to port. The article quoted a tweet from Elon, “This was a three-engine landing burn, so triple deceleration of last flight. That’s important to minimize gravity losses.”

There was also an article by William Graham covering the launch itself and describing the landing burn this way, "The success was also aided by the multi-engine landing burn option, with three – as opposed to one – Merlin 1D igniting for touchdown."

The JCSAT-14 was a GTO launch and the 3rd successful landing, after LEO OG-2 on land, the SES-9 GTO mishap, and LEO CRS-8 on the droneship.

https://www.nasaspaceflight.com/2016/05/third-recovered-falcon-9-first-stage-port-canaveral/
https://www.nasaspaceflight.com/2016/05/falcon-9-jcsat-14-launch/

[Kabloona]

Hans Koenigsmann, SpaceX’s Vice President for Mission Assurance, said in a press conference before the CRS-5 mission that it would take about one to two hours after a landing for the crew to safe the stage remotely before boarding the drone ship. Remote-controlled safing activities would likely include venting pressurized helium from the fuel tank and venting residual LOX.
https://www.nasaspaceflight.com/2015/06/spacex-augments-upgrades-drone-ship-armada/

Which works well if the stage has power, and the antennas are in line of sight and not underwater.

I'm pretty sure Hans meant autonomously, not literally "remote controlled". I highly doubt they would have a human in the loop instead of having the stage pre-programmed to safe itself. If true, the stage should should vent everything as soon as it confirms altitude and velocity are zeroed.

Admittedly a bit OT for this thread, but as the author of the article quoted above, I can confirm that Hans did say it would take 1-2 hours for the crew to approach and "remotely" safe the stage before they could board the ASDS. We did have some debate here as to whether the 1-2 hours was mainly the time needed for GO Quest to get back to the ASDS, or mainly the time needed to safe the stage, or some combination thereof. His statement was admittedly ambiguous.

Having said that, it does now seem likely that the stages do some, possibly all, of the safing automatically. For example, we can see the LOX tank venting immediately after landing, which is undoubtedly automatic. Possibly the venting has always been automatic. But that quote from Hans was early in the recovery program, and it wouldn't suprise me if SpaceX has refined the safing process since then to be more (or all) autonomous, if it wasn't entirely so in the beginning.

[Star One]

Hmm... no orbital data published

43178SES-16/GOVSAT-12018-013A        PAYLOAD
43179FALCON 9 R/B        2018-013B        ROCKET BODY

As a military communications satellite I’d thought this would be classified.

[Steven Pietrobon]

Here's a cropped, enlarged and enhanced image of the first stage in the ocean.