STS-125: Processing Latest (OPF, VAB)

• #780 by rdale on 29 Sep, 2008 22:34
• Ed - This whole program was declared dead in 1990. HST has a record of coming back from adversity. Team works miracles, I'm not too concerned.
  
  This failure was anticipated 20 years ago, we have hardware on the ground ready to go.
• #781 by rdale on 29 Sep, 2008 22:36
• Someone still confused - is there any way this launch still occurs even without the spare hardware?
  
  Ed - barring some unforseen circumstance, I see no way that'll happen.
  
  What's Hubble's status now?
  
  If/when we get Side B back up, WFPC and ACS and FGS can still do science for next few months until SM4.
• #782 by rdale on 29 Sep, 2008 22:36
• Preston - we do astrometry science with FGS, which is independent of this unit. Still doing science even right now, moving astrometry science up to now until we switch to Side B>
• #783 by rdale on 29 Sep, 2008 22:38
• Something have to leave cargo bay to fit this in weight-wise?
  
  Preston - no. Sufficient space on two carriers, thinking is MULE carrier at back of cargo bay is spot to go.
  
  Lift capacity of orbiter just fine, and by putting on MULE we're putting behind the orbiter's C/G so unload ballast in the orbiter as a result.
• #784 by rdale on 29 Sep, 2008 22:38
• Will new tools be needed?
  
  Preston - no.
• #785 by rdale on 29 Sep, 2008 22:39
• mkirk - any constraint to current configuration of HST? If you can't bring up Side B, any harm?
  
  Preston - no. Limited instrument telemetry, so we can bring up the NSSC1 payload computer that supervises instruments so we can get their condition, but we're fine in this state indefinitely.
• #786 by rdale on 29 Sep, 2008 22:40
• nat geog - confused about plans. Are you switching to Side B until you can fix Side A?
  
  Preston - clarify. Side B and Side A are on same tray, so will switch to Side B, but failed equipment will change out both A&B.
• #787 by rdale on 29 Sep, 2008 22:42
• Any experiments at risk while we're delayed?
  
  Preston - data that we've taken so far has been dumped, so future observations are on hold but chances still exist in the future. So most of the planned obs will just be rescheduled for once Side B is back. Very little in the way of lost science. Certainly any target that comes and goes now would not be recoverable, but those are rare events anyways.
• #788 by rdale on 29 Sep, 2008 22:43
• Ed - this is not an unusual circumstance. Over the 18 years, Hubble has been in safe mode before. You lose a few days or week of science, but for critical obs they get rescheduled.
  
  Nat Geog - whose science got lost?
  
  Ed - we'll reschedule what was lost.
  
  PReston - read the Hubble daily report to see all the obs we do per day.
• #789 by rdale on 29 Sep, 2008 22:46
• Andrew from Science Magazine - was there any discussions about putting spare in SM4 or was it assumed this would work?
  
  Preston - we never talked seriously about changing it out, but we were concerned about lack of capability to crosstrap A&B sides. We developed kit to link those sides for more redundancy. Originally that was in early Hubble design, but too complicated. So when we developed this fix plan last year, we realized it was still pretty complex and not worth it. There are other components on observatory that have redudant parts, so we can't change everything just because it might break later.
  
  Ed - if a unit survives the first month or two, it'll last a long long time. If a radio has been working 18 years - do you really want to unplug it and try a new one? Voyager has worked 40 years, this isn't something you replace just for the sake of replacing.
• #790 by rdale on 29 Sep, 2008 22:48
• Andrew - are there other parts you are looking at?
  
  Ed - that's the decision we've already made. That's why we're waiting a few months on the final mission to make sure we're fully redundant.
  
  Presston - when we switch over to Side B, we have to switch over 5 electronics boxes, and those now become additional single points of failure to science mission. That's why we looked at cross-strapping kit to eliminate those single points.
• #791 by rdale on 29 Sep, 2008 22:50
• Irene - idea on how long the telescope ops are suspended while switching to Side B?
  
  Presston - original plan was to switch to Side B end of this week, now looking to be a day or two delay while complete engineering assessments. Actual switchover takes a full day, then we bring up instruments, so we'll be back doing science within a few days after switchover. Overall total within two weeks of today we'll be back in full ops.
• #792 by rdale on 29 Sep, 2008 22:51
• Irene - if spare doesn't check out properly, would Hubble mission move back to October?
  
  Presston - if spare isn't viable option, we'd want to fly as soon as we can, but that'd be up to John. Maybe a one month delay, but we can't keep shuttle side hanging.
  
  John - there's more to come in troubleshooting, if they can't flight qualify the spare, we'd just adjust our scheduled.
• #793 by rdale on 29 Sep, 2008 22:52
• Peter King - Weighs 135 pounds - but what is the size of replacement?
  
  Presson - 21.5" x 32.5" x 9.5"  Easy box to manipulate in space, certainly when compared to instruments / FGS / battery modules / etc.
• #794 by rdale on 29 Sep, 2008 22:54
• How many original elements will be left after SM4?
  
  Presson - electrical power system has been almost totally replaced. 3rd generation of solar arrays. New PCU (heart) on last mission, new batteries coming. So lot of components haven't been changed, but many big things are new.
• #795 by rdale on 29 Sep, 2008 22:57
• Another questioner asking if they are confident ground unit will work.
• #796 by Ronsmytheiii on 29 Sep, 2008 22:59
• Thanks CollectSpace for asking my question
• #797 by rdale on 29 Sep, 2008 22:59
• Robert Pearlman - if you launch Endeavour first, are there any challenges with Discovery as STS-400?
  
  John - kicked off work on software for STS119, but if STS-127 is the LON then we're fine. Either way doesn't sound like he's too worried about it.
  
  Robert - holding pad longer than expected, how will that affect Ares X?
  
  John - have been talking to Constellation all day, there are some things we can do like lightning towers. Bigger concern is MLP that STS125 is on, since that's need for I-X. NEed to discuss how to work that if 125 is delayed.
• #798 by rdale on 29 Sep, 2008 23:00
• Did you notice signs of failure before it happened?
  
  Presson - no. Even looked over telemetry again, and no trend info that pointed to this.
• #799 by rdale on 29 Sep, 2008 23:02
• Since this is last SM, I'm surprised that this wasn't ready for launch anyways.
  
  Presson - would take tremendous amount of money and time to launch every backup we could possibly do. Weigh that against risk we're taking. Huge inventory of hardware that can be changed out, depends on affordabillity and resources.
  
  Ed - and priorities. If you want to replace everything that works with everything we have spares for on ground, it'd be overwhelming. If we only had 3 full EVA's and room for two more, we'd add more, but that's not the case.
  
  Telecon ended.