Author Topic: SpaceX Falcon 9 v1.1 - Dragon - CRS-5/SpX-5 -Jan. 10, 2015 - DISCUSSION (Read 618063 times)

Jim · « **Reply #640 on:** 01/09/2015 06:53 pm »

Quote from: sdsds on 01/09/2015 06:29 pm

Shouldn't rendezvous be relatively simple (low delta-v) regardless of whether ISS were someplace on the opposite side of the globe at that moment, or directly overhead?

It is the time to rendezvous that is the issue. The Dragon can only go so low to catch up to the ISS and this determines the closing rate.

yokem55 · « **Reply #641 on:** 01/09/2015 09:11 pm »

Space flight 101 is reporting that the TVC actuator was in fact replaced. http://www.spaceflight101.com/dragon-spx-5-mission-updates.html

TomH · « **Reply #642 on:** 01/09/2015 09:43 pm »

Quote from: pericynthion on 01/09/2015 06:23 pm

Yes, you get two plane crossings every day, but the relative position of the ISS within the plane is also important. If it's in the wrong place the rendezvous can involve several days of hanging around in a low orbit catching up to the station, which mission planners prefer to avoid. This is the phase angle issue that Shanuson and Galactic Penguin were getting at.

Somebody correct me if I'm wrong, but plane crossings in the early morning are preferred and those in the afternoon avoided because of weather patterns on the Atlantic, especially in summer and early fall. Mornings are more tranquil and afternoon storms in summer/fall can develop quickly and unpredictably. Let's say you miss a morning window, but there's a same day afternoon window; usually they will not try that because of the higher probability of afternoon storms. Is this correct, and how much more stable is afternoon weather at this time of year?

pericynthion · « **Reply #643 on:** 01/09/2015 10:02 pm »

I thought it was a launch azimuth / land overflight issue

ArbitraryConstant · « **Reply #644 on:** 01/09/2015 11:12 pm »

Quote from: pericynthion on 01/09/2015 10:02 pm

I thought it was a launch azimuth / land overflight issue

That cuts it from two opportunities per day to one.

Rocket Science · « **Reply #645 on:** 01/10/2015 12:04 am »

NASA TV coverage begins at 3:30am ET.

adrialk · « **Reply #646 on:** 01/10/2015 12:07 am »

Does anybody know if playalinda will be open early tomorrow morning for the launch? They opened early for the last attempt but only barely. I am down here for work and wasn't able to call them today to find out.

I have wanted to see a launch forever and this may be my only chance for a long time so I apologize if this is perceived aa OT in what seems to be a mostly technical forum. BTW I already tried a search.

Thanks,
Adrial

Robotbeat · « **Reply #647 on:** 01/10/2015 05:59 am »

What's the sea state for where the ASDS will hang out (and what is its "limit")?

What are the odds of weather being good enough to launch?

Finally, does anyone have a "viewing circle" map for this launch?

ericspittle · « **Reply #648 on:** 01/10/2015 07:09 am »

Quote from: Robotbeat on 01/10/2015 05:59 am

What's the sea state for where the ASDS will hang out (and what is its "limit")?

What are the odds of weather being good enough to launch?

Finally, does anyone have a "viewing circle" map for this launch?

Edit: now 10% change of violating launch constraints, so 90% chance of go as far as weather

Steven Pietrobon · « **Reply #649 on:** 01/10/2015 07:09 am »

Weather is 90% go. Sea levels have to be less than 1.5 metres.

ericspittle · « **Reply #650 on:** 01/10/2015 07:15 am »

Quote from: Steven Pietrobon on 01/10/2015 07:09 am

Weather is 90% go. Sea levels have to be less than 1.5 metres.

Have we received any sort of confirmation on whether those sea levels are actual constraints? Is the plan to just ditch in water if sea state is too high?

It doesn't make sense to me to not try it and learn what they can no matter what. I don't imagine that an almost completely empty first stage could really do all that much damage to the barge even in a worst case scenario so I really don't understand what they have to lose by aiming for it and hoping for the best regardless of weather conditions.

It'll be interesting to see once they get this whole landing thing down if the weather at the landing site will end up being able to scrub launches or not.

Steven Pietrobon · « **Reply #651 on:** 01/10/2015 07:22 am »

Quote from: ericspittle on 01/10/2015 07:15 am

Have we received any sort of confirmation on whether those sea levels are actual constraints? Is the plan to just ditch in water if sea state is too high?

Its an actual launch constraint, which was shown during the last launch attempt during the weather briefing.

laika_fr · « **Reply #652 on:** 01/10/2015 07:27 am »

Wind has picked up a bit where the barge is located, since last attempt, ~30km/h this time.

ericspittle · « **Reply #653 on:** 01/10/2015 07:31 am »

Quote from: Steven Pietrobon on 01/10/2015 07:22 am

Quote from: ericspittle on 01/10/2015 07:15 am
Have we received any sort of confirmation on whether those sea levels are actual constraints? Is the plan to just ditch in water if sea state is too high?

Its an actual launch constraint, which was shown during the last launch attempt during the weather briefing.

If I recall correctly that particular item has been on at least one previous launch as well, and the launch continued as planned despite it being violated. I think it is more for information purposes and for getting the range used to seeing it as a part of the mission than an actual launch constraint.

Especially on these NASA missions I have my doubts they will be allowed to scrub a launch for something that will not be a danger to the actual mission. Obviously I'm not privy to the terms of the contract, but it wouldn't make sense for a customer to shoulder a potential delay in launch for something immaterial to the actual mission, and after listening to the press conference held last week (with the repetition of the idea that the reason for the launch is to deliver supplies to ISS and nothing else) I'm pretty comfortable in that opinion.

the_other_Doug · « **Reply #654 on:** 01/10/2015 07:58 am »

What's the length of today's launch window? In case we have to hold for the thick cloud rule, that is.

Also, anyone know for certain what camera feeds might be available live for the first stage descent burn and/or at the barge?

faramund · « **Reply #655 on:** 01/10/2015 08:02 am »

Its an instantaneous (1 second) launch window.

grythumn · « **Reply #656 on:** 01/10/2015 08:03 am »

Quote from: the_other_Doug on 01/10/2015 07:58 am

What's the length of today's launch window? In case we have to hold for the thick cloud rule, that is.

Also, anyone know for certain what camera feeds might be available live for the first stage descent burn and/or at the barge?

SpaceX ISS launches have an instantaneous window. The Antares ISS launches had a 10 minute window.

-Bob

ericspittle · « **Reply #657 on:** 01/10/2015 08:03 am »

Quote from: the_other_Doug on 01/10/2015 07:58 am

What's the length of today's launch window? In case we have to hold for the thick cloud rule, that is.

Also, anyone know for certain what camera feeds might be available live for the first stage descent burn and/or at the barge?

Instantaneous launch window. Technically 1 second, but any hold is the same thing as a scrub unfortunately.

According to SpaceX at last week's presser there will be no live coverage of the landing. They hope to have video available within a day but offered no guarantees. They did say they expect that news of a landing (if it happens of course) will leak out very quickly after, so at least we should know in short order.

enkarha · « **Reply #658 on:** 01/10/2015 08:24 am »

I expect Musk himself would deliver the news in short order, as he's been pretty forthcoming with how the landing attempts have gone in the past.

Norm38 · « **Reply #659 on:** 01/10/2015 08:27 am »

That "FTS" issue sounds pretty minor. But they need a voting receiver if they're having multipath issues.