Author Topic: LIVE: SpaceX Falcon 9/Dragon CRS-2 (SpX-2) LAUNCH and FD-1 UPDATES (Read 278950 times)

wronkiew · « **Reply #440 on:** 03/01/2013 07:15 pm »

Musk: Nominal pressure on all four tanks, but #2 and 3 thrusters not enabled yet.

Jim · « **Reply #441 on:** 03/01/2013 07:16 pm »

Quote from: kevin-rf on 03/01/2013 07:13 pm

Quote from: Chris Bergin on 03/01/2013 07:11 pm
All four oxidizer tanks holding their pressure now.

Does this mean that they used up pressurant (I assume helium) to try to bring the tanks up to pressure and now have reduced pressurant available for the rest of the mission?

It doesn't go overboard. The helium is in high pressure bottles and isolated from the prop tanks. As prop is used, the helium has to be added to the prop tank to maintain pressure.

Chris Bergin · « **Reply #442 on:** 03/01/2013 07:17 pm »

NSF Philip on the presser!

On departure ops:

Constricted around the 15th.

Great question to Elon about charging the thrusters post-sep, but PAO cut off before Elon could answer. Blah.

wronkiew · « **Reply #443 on:** 03/01/2013 07:17 pm »

Next operation on station to protect is March 15. Potential berthing conflict.

Star One · « **Reply #444 on:** 03/01/2013 07:17 pm »

Quote from: Jim on 03/01/2013 07:16 pm

Quote from: kevin-rf on 03/01/2013 07:13 pm
Quote from: Chris Bergin on 03/01/2013 07:11 pm
All four oxidizer tanks holding their pressure now.

Does this mean that they used up pressurant (I assume helium) to try to bring the tanks up to pressure and now have reduced pressurant available for the rest of the mission?

It doesn't go overboard. The helium is in high pressure bottles and isolated from the prop tanks. As prop is used, the helium has to be added to the prop tank to maintain pressure.

What could have caused the blockage?

cro-magnon gramps · « **Reply #445 on:** 03/01/2013 07:17 pm »

Quote from: Elmar Moelzer on 03/01/2013 07:15 pm

Wow hardware issue? That is weird. Glad they were able to fix it, but what does that mean for future missions?

doesn't sound like hardware, but fuel contamination...

Borklund · « **Reply #446 on:** 03/01/2013 07:17 pm »

Elon Musk: "Dragon able to be in orbit for several months in theory"

Lar · « **Reply #447 on:** 03/01/2013 07:17 pm »

Mike (spaceflight now?) - How long can the Dragon loiter before it has to come home, and what is the cargo/contract situation

E - Dragon can be on orbit for several months in theory, but we would not, however we may keep it for as much as month... we plan to do the perigee raise burn quite soon. Contractually, if we don't get cargo there and cargo back we only receive partial payment.

Jason: are there contingency plans for a faillure once the vehicle is in the safe zone.

Suff: we will not allow the vehicle in and will not waive it, unless we are convinced the system is healthy and redundancy required is present.

Jason" but what if something happens once inside??? what then? what continegency plan

Suff: with 3, you can still back away if one fails. with 4, you can lose one and keep approaching. we have plans for every failure mode you can imagine,

Q: worse case, if no delivery, what adjustments, what problems what impacts to ISS if the delviery doesn't happen

Suff: we are healthy relative to supply and capacity, we lose (if Dragon doesn't show) is research hardware... but we have stuff to keep the astros busy til September... the significance of the loss is the type of research we planned, some specific stuff we wanted to do.... vehicle and crew are not at risk if we miss this delivery.

Danderman · « **Reply #448 on:** 03/01/2013 07:18 pm »

Quote from: mlindner on 03/01/2013 06:56 pm

How long for a 360 degree precession?

At one degree per day, one year.

Kabloona · « **Reply #449 on:** 03/01/2013 07:18 pm »

Quote from: Star One on 03/01/2013 07:17 pm

Quote from: Jim on 03/01/2013 07:16 pm
Quote from: kevin-rf on 03/01/2013 07:13 pm
Quote from: Chris Bergin on 03/01/2013 07:11 pm
All four oxidizer tanks holding their pressure now.

Does this mean that they used up pressurant (I assume helium) to try to bring the tanks up to pressure and now have reduced pressurant available for the rest of the mission?

It doesn't go overboard. The helium is in high pressure bottles and isolated from the prop tanks. As prop is used, the helium has to be added to the prop tank to maintain pressure.

What could have caused the blockage?

One possible failure mode: stuck closed check valve.

wronkiew · « **Reply #450 on:** 03/01/2013 07:18 pm »

Musk: Dragon is capable of staying on orbit for several months. Willing to keep it up for a month at least.

Jim · « **Reply #451 on:** 03/01/2013 07:19 pm »

Quote from: cro-magnon gramps on 03/01/2013 07:17 pm

Quote from: Elmar Moelzer on 03/01/2013 07:15 pm
Wow hardware issue? That is weird. Glad they were able to fix it, but what does that mean for future missions?

doesn't sound like hardware, but fuel contamination...

it was helium valves, no propellant involved.

Occupymars · « **Reply #452 on:** 03/01/2013 07:21 pm »

can some one give me a link to this telecon please

simonbp · « **Reply #453 on:** 03/01/2013 07:21 pm »

http://www.ustream.tv/channel/nasa-news-audio

AJA · « **Reply #454 on:** 03/01/2013 07:22 pm »

Quote from: Jim on 03/01/2013 07:16 pm

Quote from: kevin-rf on 03/01/2013 07:13 pm
Quote from: Chris Bergin on 03/01/2013 07:11 pm
All four oxidizer tanks holding their pressure now.

Does this mean that they used up pressurant (I assume helium) to try to bring the tanks up to pressure and now have reduced pressurant available for the rest of the mission?

It doesn't go overboard. The helium is in high pressure bottles and isolated from the prop tanks. As prop is used, the helium has to be added to the prop tank to maintain pressure.

Wait, how do you cycle without dumping some Helium? As in, once you pressurise higher, to cycle back down to low pressure on the Oxidiser, don't you have to dump some gas?

ugordan · « **Reply #455 on:** 03/01/2013 07:22 pm »

Quote from: Jim on 03/01/2013 07:19 pm

it was helium valves, no propellant involved.

So if I'm understanding this correctly, this lead to lower pressure in certain tanks and hence thruster pod inhibit, i.e. it's not blockage between propellant and actual thrusters?

Does that mean nominal pressure in tanks (as being reported shortly ago) means there is nothing preventing the other two pods from working now?

Lar · « **Reply #456 on:** 03/01/2013 07:23 pm »

AP: can you rendezvous on Sun or Mon, and were you dismayed?

E - we will not be rushing things, we will make sure first and foremost we will make things safe. Of course we were a bit alarmed, but the F9 is "perfect" (SUPER WELL in Elon speak)... some press confused rocket with spacecraft.... we noticed the issue with the thrusters after sep.... after non engagement we saw the oxidizer pressure was low in 3 of 4 tanks, we have spent the time since then working on why and getting things back...

Note that there is no leakage, no debris, nothing like that, that we are aware off

AP: so is the weekend off?

E: probably, but since we only just brought things back on line it's hard to say for sure

Someone :Marsha (AP), don't go to sleep on us, keep reporting...

E - maybe sunday

newQ: how much time did the solar array buy, and what would this have meant if this was a crewed flight?

E - at first we were going to get to 2 before deploying but the temp in the array actuators was dropping and a sim said maybe we should deploy before it got too cold... as it turns out extending the arrays slowed the rotation rate of the craft (like an ice skater extending arms)... Crewed version won't have solar arrays, just a really big battery pack (unless it is long duration)

wronkiew · « **Reply #457 on:** 03/01/2013 07:23 pm »

Suff: What we lose if dragon doesn't show up is research hardware. Have specific research on this Dragon flight that will have to go on a repeat flight.

emerrill · « **Reply #458 on:** 03/01/2013 07:23 pm »

Quote from: AJA on 03/01/2013 07:22 pm

Wait, how do you cycle without dumping some Helium? As in, once you pressurise higher, to cycle back down to low pressure on the Oxidiser, don't you have to dump some gas?

Cycling means opening and closing the valve, not necessarily cycling pressure.

Star One · « **Reply #459 on:** 03/01/2013 07:23 pm »

Doesn't want to comment on the exact time of the berthing at this point.