LIVE: SpaceX Falcon 9/Dragon CRS-2 (SpX-2) LAUNCH and FD-1 UPDATES

[ugordan]

None of this freezing oxidiser would happen if they stirred the tanks.

Why would they need to stir the tank if it is well-insulated and perhaps heated? And how could it cause an explosion with storable oxidiser?

Shame on you for not getting that reference! 

[mmeijeri]

I think that was an Apollo 13 joke, but not sure

Yeah, I thought it was a reference to Apollo 13, but was it a joke?

[JWag]

It seems likely that they won't know for sure that they've cleared the blockage until they actually use some oxidizer from each tank, correct?  Once some prop is used, if the tank easily maintains pressure, all is well.  If the tank takes time to re-pressurize, all is not well.

[russianhalo117]

Was this the only Falcon to have flown through heavy clouds? I wonder if there was some thermal issue on ascent that cause the systemic failure of the check valves...

Something to check for the upgraded Falcon?

probably not the case since it Did not occur previously.

[simonbp]

Something to check for the upgraded Falcon?

No, Falcon did fine. This is a Dragon issue, and one that they really need to fix considering this same RCS is evolving into the abort system for Crew Dragon.

[mmeijeri]

Shame on you for not getting that reference! 

Got the reference (hence explosion), didn't get that it was a joke.

[Galactic Penguin SST]

Was this the only Falcon to have flown through heavy clouds? I wonder if there was some thermal issue on ascent that cause the systemic failure of the check valves...

F9 01: partly cloudy, but the clouds weren't thick
SPECI KXMR 041845Z VRB05KT 7SM FEW044 SCT100 BKN200 32/25 A2995

F9 02: clear
METAR KXMR 081555Z AUTO 33007KT 10SM CLR 13/03 A3013 RMK AO2 SLP205 T01270026

F9 03: almost clear
SPECI KXMR 220752Z AUTO 00000KT 8SM R31/5500VP6000FT CLR 19/19 A2994 RMK AO2 SLP141

F9 04: only thin layer of clouds at several thousand feet (where the Merlin 1C went kaput)
METAR KXMR 080055Z AUTO 11004KT 10SM CLR 25/23 A2998 RMK AO2 SLP153 T02480231

F9 05: METAR KTTS 011455Z AUTO 32007KT 10SM OVC130 15/04 A2998 RMK AO2 SLP154 T01450044 52008

[Star One]

Something to check for the upgraded Falcon?

No, Falcon did fine. This is a Dragon issue, and one that they really need to fix considering this same RCS is evolving into the abort system for Crew Dragon.

But isn't up to the Falcon to protect the Dragon thermally on the way up?

[Chris Bergin]

Going to set up the FD-2-3 update thread to run through to the first berthing opp on Sunday later, so like at the end of a busy day at the office, this thread is now more relaxed from "Has to be an update or else"...although aim to keep it on the updates....we still have that party thread

[Norm38]

What scares me is that a single point of failure disabled 3 of 4 thruster pods.  If two sets of thrusters are needed to manuever, then there really should be two isolated subsystems, one for each pair.  I wonder if they'll look into any design changes based on this?  I would.

[AJA]

Shame on you for not getting that reference! 

Got the reference (hence explosion), didn't get that it was a joke.

My bad. http://en.wikipedia.org/wiki/Poe's_law

Btw with regard to an explosion of an oxidiser, we're not talking explosion as in combustive, but a rapid pressure release. So I wouldn't be a fan of any kind of heating element that introduces a non-uniform or anisotropic thermal stress on the tank.

[simonbp]

But isn't up to the Falcon to protect the Dragon thermally on the way up?

Nope. That's true for a payload in a faring, but Dragon is on its own thermally (and IIRC, for power and comm).

We do know that the solar actuators were colder than anticipated, so that might be a clue.

[astrobrian]

One of the shots I got from Kennedy Point Park of the launch before she went into the cloud layers

[Star One]

But isn't up to the Falcon to protect the Dragon thermally on the way up?

Nope. That's true for a payload in a faring, but Dragon is on its own thermally (and IIRC, for power and comm).

We do know that the solar actuators were colder than anticipated, so that might be a clue.

Good point I was thinking of it too much as if it was a 'passive' payload.

[Ben the Space Brit]

What scares me is that a single point of failure disabled 3 of 4 thruster pods.  If two sets of thrusters are needed to manuever, then there really should be two isolated subsystems, one for each pair.  I wonder if they'll look into any design changes based on this?  I would.

A single point of failure or, as Jim suggested on the General Discussion thread, a common failure on three units.  If it is the latter then SpaceX are going to have to possibly look at either a redesign or possibly some procedural tweaks to limit the likelihood of a occurrence.

[Star One]

Is there any links around for this launch, only saw it on my phone earlier?

[ugordan]

We do know that the solar actuators were colder than anticipated, so that might be a clue.

We know that the solar panel actuators were getting colder with time, due to them not being released immediately at sep, not because space was particularly cold today.

[mmeijeri]

We know that the solar panel actuators were getting colder with time, due to them not being released immediately at sep, not because space was particularly cold today.

Ok, thanks, I think my sarcasm detector is working again. Turns out it had a stuck valve, but fortunately I was able to pressure hammer it loose.

[Herb Schaltegger]

But isn't up to the Falcon to protect the Dragon thermally on the way up?

Nope. That's true for a payload in a faring, but Dragon is on its own thermally (and IIRC, for power and comm).

We do know that the solar actuators were colder than anticipated, so that might be a clue.

See reply #62 from this morning; there was also a report of a low-temp indication for the flight computer. Hmm.

[JWag]

Elon Musk ‏@elonmusk

Thruster pods one through four are now operating nominally. Preparing to raise orbit. All systems green.