LIVE: STS-120 Flight Day 10 - MT/OBSS Ops - EVA-4 Preps

[stockman]

sqoops - 1/11/2007  4:43 PM

DwightM - 1/11/2007  4:10 PM  

EV2 will play a critical role during SSRMS ops & the repair to watch guidance & clearance issues.  It's unlikely he'll be doing much else.

Aren't two EVs always required anyway, in the frightening case one must assist another?

I believe so. I assumed that he would fill that role for sure. I was just interested if he had any other duties while the repair effort is going on. Its not like he can physically assist but he can help spot for clearance issues as mentioned and other visual aids etc.

[davcbow]

I asked a question the other day; could the boom be attached to the station arm and could it reach, I got what seemed to me like a harsh "no" as a reply. So all I got to say about that is "I rest my case". I wish them the best of luck and a big "be careful". I know they can pull it off and be successful.

[ace007]

So when do we think we will know the schedule for the activities on Saturday.  If they start shifting their working schedule up to help with the daytime landing then maybe this spacewalk will be at a more decent hour to get up and watch.  It'll probably be worth it...

[Kel]

stockman - 1/11/2007  3:03 PM

Ok I have a question on the repair effort spacewalk planned for saturday. Its apparent that one of the astronauts will be on the boom doing the physical threading of the cufflinks as they are called with the array. My question is what is the Role of the second spacewalker throughout this period? Is he simply a passive observer for safety sake or is there an integral role for him to play during this repair? Thank you in advance

My understanding is......It will probably depend on what they find when they get out there. They are working up procedures for several different contingencies, so there will be several options available. As they mentioned in the briefing today, they still don't know exactly what is causing the hang up - and won't until Scott's helmet camera gets right up to the snag. Once they know what they're dealing with, they will make some decisions (rapidly) about what option to pursue.

[edkyle99]

steve_slitheen - 1/11/2007  2:02 PM

ckiki lwai - 1/11/2007  7:54 PM

mwfair - 1/11/2007  7:45 PM

As stated in the MSB, the array can't be safed, the cells produce voltage when light shines!  However, they have 45minutes of no light, so can Scott touch the array during orbital night?

Your question got answered
He says the protection is adequate so he sees no reason not to continue the activities in daylight

edit:spelling

So what kind of voltages and currents are we talking about here?

According to this paper,

http://www.grc.nasa.gov/WWW/RT/2003/6000/6920gustafson.html

Each Solar Array Wing has 82 strings of cells, which are connected together somehow to generate 124 volts DC power, although the voltage out on the Wings themselves can be as high as 160 volts.  Each string can produce an average of nearly 2.7 amperes of short circuit current.  

What I don't know is the electrical configuration that would present itself in a small work location on one of the wings.  I doubt that an astronaut can be exposed to the full 160 Volt DC potential when working at one spot, for example.

Differential charging may be a more important concern.

http://science.nasa.gov/headlines/y2001/ast13nov_1sidebar.htm

 - Ed Kyle

[Bret]

Who would have ever dreamed that we would have a former ER physician doing emergency surgery on a solar array?  Think Scott will be able to sleep Friday night?

[Bubbinski]

The TV schedule Rev. J is up on the nasa.gov website under http://www.nasa.gov/multimedia/nasatv/mission_schedule.html - it states that crew wakeup on Saturday is scheduled for 12:38 am Central and EVA start for 5:28 am Central.  I'll be awake, wide awake!

[Joffan]

Will the spacewalkers stay out there to observe the remaining extension of the solar wing after a successful repair?

[rdale]

ace007 - 1/11/2007  4:51 PM

So when do we think we will know the schedule for the activities on Saturday.

They have to send up the final documents before crew wakeup tomorrow - so anything too specific probably won't come for a bit yet...

[rdale]

Joffan - 1/11/2007  6:05 PM

Will the spacewalkers stay out there to observe the remaining extension of the solar wing after a successful repair?

It's desired - but again depends on the timing of everything. Asked near the end of the press conference.

[ETEE]

On EVA4, Wheels will have to get the camera they left outside during EVA3.

[bsegal]

Just listened to the briefing from earlier today - thanks John44.  There was a decent amount of discussion regarding how the guide wires might be dealt with if they had to cut it.  I'm surprised they didn't mention the most obvious solution to any concern about how it would reel back in and potentially catch - simply have EV2 cut the wire from the bottom of the blanket box to remove any reeling tension, then have EV1 cut out the snag with no risk at that point of the guide wire moving at all.  They already said the other day they don't need those guide wires for deploy - only retraction.  And we won't be retracting this array ever again.

[Speedracer]

bsegal - 1/11/2007  7:23 PM

Just listened to the briefing from earlier today - thanks John44.  There was a decent amount of discussion regarding how the guide wires might be dealt with if they had to cut it.  I'm surprised they didn't mention the most obvious solution to any concern about how it would reel back in and potentially catch - simply have EV2 cut the wire from the bottom of the blanket box to remove any reeling tension, then have EV1 cut out the snag with no risk at that point of the guide wire moving at all.  They already said the other day they don't need those guide wires for deploy - only retraction.  And we won't be retracting this array ever again.

Then you run the risk of entanglement with the wire getting snagged in the Astronaut's gear, another part of the array, the OBSS, etc.

He might not be able to wind it around from his position on the OBSS and would have to tug on it, which could lead to more damage, or even (if that wire is conductive) electric shock.

BTW:  Who's the PAO now?  I've not heard her before.

[reubenb]

I've submitted the front page stories about this stuff to Digg so that the community over there can get some space articles that aren't the panicky CNN things that usually get posted.  Anyone with a Digg account should go over there and digg it up.  http://digg.com/space/NASA_hard_at_work_on_complex_array_repair_plan

[Jackson]

Fine work reubenb!!

[Chris Bergin]

Thanks Reuben.

Interesting reference from an L2 comment about the last major EVA repair to a Solar Panel on  a station was Skylab 2.

While we're in the lull before the storm, are we heading towards that comparison? Or are we more in the Beamer shakes area? I Would say we're well above the Beamer shakes, but to those who are old enough..Skylab 2? Pushing it a bit?

[Jim]

It is Skylab 2.  Repairing a solar array with limited access.  Success of the repair determines whether the station has sufficient power.

[lcs]

Jim - 1/11/2007  8:48 PM

It is Skylab 2.  Repairing a solar array with limited access.  Success of the repair determines whether the station has sufficient power.

Here's how they did it in those days...much of it out of communication with the ground.

[ChrisC]

Chris Bergin - 31/10/2007  12:10 AM

Oh for pity's sake.

Wake up song is "The Lion Sleeps Tonight" by some 80s band.

A late reply to this post from the beginning of this thread early this morning ...

It's funny how these astronaut and console types are so capable and accomplished but have just the most awful taste in music   (except for Stephanie, her jazz selection a couple days ago was a breathe of fresh air)

And these days that Lion song now reminds me of nothing but Ed Helms doing his blowhard act on The Office ... good stuff

[Andrewwski]

Seems you're forgetting STS-117...Suni and the iPod!