SpaceX Falcon 9/Dragon CRS-2 SpX-2 MISSION GENERAL DISCUSSION

[woods170]

Based on the Florida Today article OccupyMars posted in the update thread, it looks like SpaceX ended up about where I thought they might. They have theories on the engine issue but no real root cause.

That usually is the case when the failed component in question has not been recovered from the ocean floor. With no examination performed on the actual engine, and only very marginal visual evidence (from launch footage) it can be quite hard to pin down the root cause.

No, there is plenty of telemetry info. The image only shows the implosion due to pressure drop.

I said it can be quite hard to pin down the root cause. I did not mean to imply that in this particular case it has been hard to pin down the root cause.
On the other hand, there have been (partial) launch failures with very hard to pin down root causes, despite the fact that there was plenty of telemetry info. Point is: telemetry alone does not provide the whole picture. Investigators usually like to get their hands on as much information and material as they can get, be it telemetry, launch footage, recovered hardware, etc.

[Elmar Moelzer]

Based on the Florida Today article OccupyMars posted in the update thread, it looks like SpaceX ended up about where I thought they might. They have theories on the engine issue but no real root cause.

That usually is the case when the failed component in question has not been recovered from the ocean floor. With no examination performed on the actual engine, and only very marginal visual evidence (from launch footage) it can be quite hard to pin down the root cause.

No, there is plenty of telemetry info. The image only shows the implosion due to pressure drop.

I said it can be quite hard to pin down the root cause. I did not mean to imply that in this particular case it has been hard to pin down the root cause.
On the other hand, there have been (partial) launch failures with very hard to pin down root causes, despite the fact that there was plenty of telemetry info. Point is: telemetry alone does not provide the whole picture. Investigators usually like to get their hands on as much information and material as they can get, be it telemetry, launch footage, recovered hardware, etc.

I actually think so as well. Telemetry usually only tells you what failed, not always why it failed at that moment. E.g. it seems (!) like SpaceX is having trouble determining why the fuel dome of that engine failed during this launch (and did not do so during the extensive tests before). If I interpret their somewhat vague press releases correctly, then they THINK that it was because of the stress from previous tests, or at least that these contributed to the failure. I have a feeling that they are not entirely sure though why if failed there and then.

[Norm38]

Clean suits and dust sheets up! I'm sure Jim will be pleased as punch to see the SpaceX crew looking so much more 'professional' (i.e. NASA-like) than usual.

You have cleaner environment in a small SMD electronics assembly company...

This is really a question about technical requirements, because no one in my SMD electronics factory has ever worn cleansuits, caps and booties, and honestly, the SpaceX hanger looks cleaner than our factory.  The most we ever do is spray high voltage boards with a conformal coating.  Otherwise the boards go into the housings, housings into chassis, and that's it.

When the flight hardware gets to the hanger, everything delicate like a circuit board is already buttoned up and sealed.  With things like the DragonEye excepted, how sensitive to dust and dirt can the rocket really be at that point?

Even the solar arrays shouldn't be an issue.  MER Opportunity has been sitting on Mars covered in dust for nearly a decade now and the solar cells still work.  How much impact can a little dust have on a solar array that only has to work for two weeks?

I'm just trying to separate good practice from firm requirements, because it seems to me that cleansuits and clean rooms shouldn't be necessary at the hangar.

[padrat]

You still need to get into the capsule for various jobs, plus access other areas on the capsule and trunk, which definately requires a clean room and bunny suits

[joertexas]

Yep, I would think it is more to protect against damaging the dragon-eye, star trackers, and other instruments.

Here is a great shot from ISS that shows what is in the bay: (very high res)

That is hi-rez - I can practically inspect the safety wires on the bolts 

JR

[mr. mark]

Its covered for cleanliness

Any upgrades to either Dragon or recovery for this mission? I heard there was some cargo damage after splashdown on the last flight.

[mr. mark]

I guess I will answer my own question....

"Another issue with the CRS-1 flight was the loss of power to a freezer carrying biological samples on the spacecraft upon splashdown. Suffredini said that none of the samples were compromised by the loss of freezer power. He said SpaceX was working to limit water intrusion into those systems. “The fix that was necessary was to a better job of sealing up the boxes,” he said. Those components will be sealed up better for CRS-2, with an “ultimate” redesign planned for CRS-3".

http://www.newspacejournal.com/2013/01/25/spacex-prepares-for-its-next-iss-mission-while-orbital-inches-closer-to-flight/

[krytek]

I still can't get over at how much sci-fi the dragon with it's fairings looks.

[Lurker Steve]

I guess I will answer my own question....

"Another issue with the CRS-1 flight was the loss of power to a freezer carrying biological samples on the spacecraft upon splashdown. Suffredini said that none of the samples were compromised by the loss of freezer power. He said SpaceX was working to limit water intrusion into those systems. “The fix that was necessary was to a better job of sealing up the boxes,” he said. Those components will be sealed up better for CRS-2, with an “ultimate” redesign planned for CRS-3".

http://www.newspacejournal.com/2013/01/25/spacex-prepares-for-its-next-iss-mission-while-orbital-inches-closer-to-flight/

I'm still trying to determine how sea water got into these systems. The freezer is inside the pressure vessel, right ? The pressure vessel is air-tight, which I assume also means water-tight.

So was there a leak in the pressure vessel, or did the recovery team screw-up, and leave a hatch open to the elements, so that the water could enter ?
Perhaps this is an issue with the recovery vessel, where the deck is so close to the water line.
 

[ugordan]

The power to the freezer was lost, AIUI.

[Herb Schaltegger]

I guess I will answer my own question....

"Another issue with the CRS-1 flight was the loss of power to a freezer carrying biological samples on the spacecraft upon splashdown. Suffredini said that none of the samples were compromised by the loss of freezer power. He said SpaceX was working to limit water intrusion into those systems. “The fix that was necessary was to a better job of sealing up the boxes,” he said. Those components will be sealed up better for CRS-2, with an “ultimate” redesign planned for CRS-3".

http://www.newspacejournal.com/2013/01/25/spacex-prepares-for-its-next-iss-mission-while-orbital-inches-closer-to-flight/

I'm still trying to determine how sea water got into these systems. The freezer is inside the pressure vessel, right ? The pressure vessel is air-tight, which I assume also means water-tight.

So was there a leak in the pressure vessel, or did the recovery team screw-up, and leave a hatch open to the elements, so that the water could enter ?
Perhaps this is an issue with the recovery vessel, where the deck is so close to the water line.
 

My engineering-based guess is that water intruded through a cabin pressure relief/equalization valve.

[DavidH]

The power to the freezer was lost, AIUI.

My engineering-based guess is that water intruded through a cabin pressure relief/equalization valve.

As was said above. The POWER to the freezer was lost. Water did NOT intrude into the freezer or the pressure vessel, but instead, knocked out the POWER to the freezer. The power supply subsystem must, obviously, be OUTSIDE the pressure vessel.

[Robotbeat]

The power to the freezer was lost, AIUI.

And just so we are clear, NO samples were compromised because of the loss of power.

[Jim]

The power to the freezer was lost, AIUI.

My engineering-based guess is that water intruded through a cabin pressure relief/equalization valve.

As was said above. The POWER to the freezer was lost. Water did NOT intrude into the freezer or the pressure vessel, but instead, knocked out the POWER to the freezer. The power supply subsystem must, obviously, be OUTSIDE the pressure vessel.

Wrong, Herb's guess is very credible. 

[Robotbeat]

The power to the freezer was lost, AIUI.

My engineering-based guess is that water intruded through a cabin pressure relief/equalization valve.

As was said above. The POWER to the freezer was lost. Water did NOT intrude into the freezer or the pressure vessel, but instead, knocked out the POWER to the freezer. The power supply subsystem must, obviously, be OUTSIDE the pressure vessel.

Wrong, Herb's guess is very credible. 

Is that a hint?

[Jim]

The power to the freezer was lost, AIUI.

My engineering-based guess is that water intruded through a cabin pressure relief/equalization valve.

As was said above. The POWER to the freezer was lost. Water did NOT intrude into the freezer or the pressure vessel, but instead, knocked out the POWER to the freezer. The power supply subsystem must, obviously, be OUTSIDE the pressure vessel.

Wrong, Herb's guess is very credible. 

Is that a hint?

no, just making a point that the power supply subsystem is not obviously outside the pressure vessel and if it was, that still doesn't mean water in the cabin couldn't have an effect on the power to the freezer.

[dmgaba]

Vis a vis the Freezer Power Failure issue did not Mr. Suffredini say at the recent ISS increment 35-36 press conference that a box in the power supply system to the freezer lies outside the pressure vessel and that is is known to be inadequately sealed, with a permanent fix (redesign of the box) agreed to for SpX3 flight, but with an agreed upon plan for mitigation for the upcoming SpX2 flight (better sealing of existing box) that they expect will improve matters for this one flight.

[DavidH]

Vis a vis the Freezer Power Failure issue did not Mr. Suffredini say at the recent ISS increment 35-36 press conference that a box in the power supply system to the freezer lies outside the pressure vessel and that is is known to be inadequately sealed, ...

Say again your last, dmgaba. I did not copy.

[Lars_J]

Say again your last, dmgaba. I did not copy.

[mlindner]

The power to the freezer was lost, AIUI.

My engineering-based guess is that water intruded through a cabin pressure relief/equalization valve.

As was said above. The POWER to the freezer was lost. Water did NOT intrude into the freezer or the pressure vessel, but instead, knocked out the POWER to the freezer. The power supply subsystem must, obviously, be OUTSIDE the pressure vessel.

Wrong, Herb's guess is very credible. 

Is that a hint?

no, just making a point that the power supply subsystem is not obviously outside the pressure vessel and if it was, that still doesn't mean water in the cabin couldn't have an effect on the power to the freezer.

No, water did not enter the pressure vessel. If it had then there would have been more damage and contamination of samples. Pristine blood and urine samples sitting in a bath of salt water would obviously contaminate things. I believe Suffredini even explicitly stated that water did not reach the freezers.

Also why in the world would they open up the capsule (there are no humans to remove) before they got the capsule up on deck and secured? If water actually got inside the pressure vessel then there would have to have been a leak in the pressure vessel which would be a much larger issue than losing the externally mounted power system.

Cleaned up dmgaba's response above to be more readable.

With respect to the Freezer Power Failure issue, Mr. Suffredini talked about it at the recent NASA ISS increment 35-36 press conference. He stated that a box in the power supply system which feeds power to the freezer lies outside the pressure vessel and is known to be inadequately sealed. A permanent fix (redesign of the box) is already planned for SpX-3 flight, but a temporary mitigation for the upcoming SpX-2 flight is planned where they seal the existing box tighter which they expect will improve matters for this one upcoming (SpX-2) flight.