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

[Chris Bergin]

The CRS-2/SpX-2 Mission Special Section now live for L2 members.

[Space Pete]

Some details on the HRSGFs from Chris Cassidy's preflight interview:

http://www.nasa.gov/mission_pages/station/expeditions/expedition35/cassidy_interview.html

[There's a] piece of equipment called a Radiator Grapple Bars that are being brought up by the SpaceX that will be launching here in beginning of March, and these are large metal beams that are used to grab on to a radiator once it’s collapsed and folded down, if it needs to be repaired, so that a robotic arm can move in and grab it and take it where it needs to go. When the SpaceX arrives, these grapple bars will be placed on a piece of equipment called the POA [payload ORU [orbital replacement unit] accommodation].

[The POA is] a place to store these grapple bars. The key thing about the POA though, it’s a place to store any equipment, and if other pieces of equipment break, that’s a planned location for these major repairs to be held temporarily if it takes multiple spacewalks to conduct the whole replacement of whatever part has failed. So that location is one that we tend to protect and have it is available if we can. Our job will be to take these grapple bars off of the POA and go place them in, one on each side, port and starboard, of the space station. That’ll take a large part of one EVA.

[Joffan]

(shifted from updates thread)

Just posted on SpaceX's YouTube channel:

By my count that's a five-second hotfire, unless the video editing has added time in.

No, it's not. You must be counting the engine shutdown flameout into the "burn".

No, I'm not counting the flameout. It's been suggested to me that there is a 3-second power ramp-up for the engines to reach full power, which combined with 2 seconds at full power would be consistent with my observation.

[ugordan]

No, I'm not counting the flameout. It's been suggested to me that there is a 3-second power ramp-up for the engines to reach full power, which combined with 2 seconds at full power would be consistent with my observation.

No, the engines are ignited at around T-3, reach significant thrust at T-2 and are shutdown at T-0. They don't run at full thrust past the normal launch commit signal.

The test setup they use, I think, uses a pad abort signal so it's cut off at the moment the vehicle would normally be released for flight.

[PreferToLurk]

No, I'm not counting the flameout. It's been suggested to me that there is a 3-second power ramp-up for the engines to reach full power, which combined with 2 seconds at full power would be consistent with my observation.

No, the engines are ignited at around T-3, reach significant thrust at T-2 and are shutdown at T-0. They don't run at full thrust past the normal launch commit signal.

The test setup they use, I think, uses a pad abort signal so it's cut off at the moment the vehicle would normally be released for flight.

Watch the video again.  From the end of the high pitch scream of engine ignition to the main cutoff (not the flameout), its about 5 seconds. So where is the extra time coming from?

[Comga]

No, I'm not counting the flameout. It's been suggested to me that there is a 3-second power ramp-up for the engines to reach full power, which combined with 2 seconds at full power would be consistent with my observation.

No, the engines are ignited at around T-3, reach significant thrust at T-2 and are shutdown at T-0. They don't run at full thrust past the normal launch commit signal.

The test setup they use, I think, uses a pad abort signal so it's cut off at the moment the vehicle would normally be released for flight.

Watch the video again.  From the end of the high pitch scream of engine ignition to the main cutoff (not the flameout), its about 5 seconds. So where is the extra time coming from?

It looked and sounded to me to be discontinuous, but there is no time clock to verify that.  That is, the video after the camera change appears to start a second or two before the former one ends.  There is something about the rising noise levels that seems to repeat.

Is there any metadata in the video with which to assess this assumption?

[jacqmans]

Remember folks we'll be going to a new live thread for launch day/FD-1 either late tonight or early in the morning. This is the nearest we get to Shuttle mission coverage - if less intense - so it's all rather exciting. (no need to respond)

This is by no means a Shuttle launch... and no different then an Ariane (ATV) launch or a Japanese H2 (HTV) launch... Just a normal Rocket launch Which we had before, this is after all the 3rd flight to ISS  of Dragon....

(Yes you can delete this post, just my "European" opinion)

[mduncan36]

Remember folks we'll be going to a new live thread for launch day/FD-1 either late tonight or early in the morning. This is the nearest we get to Shuttle mission coverage - if less intense - so it's all rather exciting. (no need to respond)

This is by no means a Shuttle launch... and no different then an Ariane (ATV) launch or a Japanese H2 (HTV) launch... Just a normal Rocket launch Which we had before, this is after all the 3rd flight to ISS  of Dragon....

Except for the level of interest. Wonder why that is? (half seriously)

[therein69]

From my standpoint it is because Falcon 9 and Dragon are the prototypes for a Human launch system and the other vehicles you mentioned have no stated plans to be so. Success here means a greater chance for that to become a reality.

[mr. mark]

Dragon/Falcon 9 are one part of a two part system, the other being Antares/Cygnus. These two commercial partners make up the foundation for US cargo resupply to the ISS. It's an important piece of the overall US strategy going forward.

[Ben the Space Brit]

Remember folks we'll be going to a new live thread for launch day/FD-1 either late tonight or early in the morning. This is the nearest we get to Shuttle mission coverage - if less intense - so it's all rather exciting. (no need to respond)

This is by no means a Shuttle launch... and no different then an Ariane (ATV) launch or a Japanese H2 (HTV) launch... Just a normal Rocket launch Which we had before, this is after all the 3rd flight to ISS  of Dragon....

Purely IMHO, this is a good thing.  We aren't on tenterhooks when Atlas-V (another CCT candidate launcher) flies because it's a mature system.  The fact that there is less worry and excitement shows that Falcon-9 is starting to get the same feel about it and this can only be a good thing.

FWIW, I think that there will be another spike for the first couple of flights of F9 v.1.1 and FH.  However, the next big thing (IMHO again) will be Dragonrider-PA1.

[oiorionsbelt]

so it's all rather exciting. (no need to respond)

and no different then an Ariane (ATV) launch or a Japanese H2 (HTV) launch... Just a normal Rocket launch

It is different Ariane (ATV) or H2 (HTV) They dont come back, they will never carry people and most importantly they don't get space geeks excited they way F9 and Dragon do.

[bunker9603]

Remember folks we'll be going to a new live thread for launch day/FD-1 either late tonight or early in the morning. This is the nearest we get to Shuttle mission coverage - if less intense - so it's all rather exciting. (no need to respond)

This is by no means a Shuttle launch... and no different then an Ariane (ATV) launch or a Japanese H2 (HTV) launch... Just a normal Rocket launch Which we had before, this is after all the 3rd flight to ISS  of Dragon....

(Yes you can delete this post, just my "European" opinion)

Please...There is a huge difference between what SpaceX is doing now and what their future plans will offer (Human Flight, Grasshopper, etc) compared to what Ariane Launch is offering...now and in the future

[Chris Bergin]

Remember folks we'll be going to a new live thread for launch day/FD-1 either late tonight or early in the morning. This is the nearest we get to Shuttle mission coverage - if less intense - so it's all rather exciting. (no need to respond)

This is by no means a Shuttle launch... and no different then an Ariane (ATV) launch or a Japanese H2 (HTV) launch... Just a normal Rocket launch Which we had before, this is after all the 3rd flight to ISS  of Dragon....

(Yes you can delete this post, just my "European" opinion)

Why would I delete that?

I didn't say it was like a Shuttle launch/mission, however. I said it was the closest we get now, because it has major flight days, and there's more interest than ATV and HTV. That's what I meant

Nothing get close to Shuttle, but they are gone. Dragon missions are the best next thing right now, and are going to be crewed, so it's exciting.

[R7]

Nothing get close to Shuttle, but they are gone. Dragon missions are the best next thing right now, and are going to be crewed, so it's exciting.

The inevitable special excitement is about "anomalies". Lots of questions about that in the preflight presser. So let's hope for very boring and uneventful flight!

[yg1968]

From my standpoint it is because Falcon 9 and Dragon are the prototypes for a Human launch system and the other vehicles you mentioned have no stated plans to be so. Success here means a greater chance for that to become a reality.

Welcome to the forum!

On the Japanese side, Japan has certain (but not yet fully funded) plans for human space flight by turning the HTV into an HTV-R and eventually into a manned capsule by 2025.  But I agree with you that SpaceX' plans are more definitive and as such are more exciting. It will be also be interesting to see the Falcon 9 v 1.1 launch in June because that should be the version that will be used for commercial crew. 

[Comga]

From the press conference:

"If solar arrays fail they may have enough battery power to make one berthing attempt."

So if they achieve several day 2 rendezvous and berthings, why not do away with the solar panels?  They might want to upgrade the batteries somewhat, but these would be recovered and potentially reused.

[Ben the Space Brit]

From the press conference:

"If solar arrays fail they may have enough battery power to make one berthing attempt."

So if they achieve several day 2 rendezvous and berthings, why not do away with the solar panels?  They might want to upgrade the batteries somewhat, but these would be recovered and potentially reused.

To maintain commonality with Dragonlab, I suppose.  Isn't that supposed to have 6-12 months untended flight endurance?

[Lars_J]

From the press conference:

"If solar arrays fail they may have enough battery power to make one berthing attempt."

So if they achieve several day 2 rendezvous and berthings, why not do away with the solar panels?  They might want to upgrade the batteries somewhat, but these would be recovered and potentially reused.

Why reduce your chance of mission success by removing a critical source of power?

[Comga]

From the press conference:

"If solar arrays fail they may have enough battery power to make one berthing attempt."

So if they achieve several day 2 rendezvous and berthings, why not do away with the solar panels?  They might want to upgrade the batteries somewhat, but these would be recovered and potentially reused.

Why reduce your chance of mission success by removing a critical source of power?

To reduce cost and increase payload.
A battery upgrade has to be less mass than the solar panels, mechanisms, and pontoons.
One could even increase reliability by removing the solar panel system with its mechanisms and wiring.
Apparently that source of power is not "critical".

Not saying SpaceX should, just that they could.