Author Topic: ISS Solar Array Tear - What Next? (Read 49440 times)

rdale · « **Reply #20 on:** 10/30/2007 05:58 pm »

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Lee Jay - 30/10/2007 1:57 PM

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rdale - 30/10/2007 11:53 AM

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ckiki lwai - 30/10/2007 1:33 PM

Or do they have to do repairs to the shuttle because there was a MMOD hit?

Stop the presses! When / where was a MMOD hit? What sort of damage did it cause?

The press already ran, and the article is on the front page.

Help me out here -- all I see is that they had indications of a possible MMOD strike... Nothing about any damage that needs repair, let alone even confirming it was MMOD. "Likely" does not mean "100%" -- anyone watching the weather forecasts should know that :cool:

Mike_1179 · « **Reply #21 on:** 10/30/2007 05:59 pm »

Transferred from the FD 8 thread:

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NYC777 - 30/10/2007 2:43 PM

Here's a what if...and I know that it's very hypothetical. Can they extend the remaining 6 bays knowing full well that there could be some more damage and utilize the arrays in that configuration?

They can do whatever they want, that's the beauty of allowing smart people to analyze the situation and determine what's best when problems arise.

However, every decision has risks and benefits. I'm reasonably sure this is one plan they are looking at, but they need to determine what happened and how bad the damage is. That way, they can make a more accurate assessment of the likelyhood of further damage happening.

The worst thing they can do is make a situation worse by guessing. Instead, they'll work the problem and find the right solution. The right solution might very well involve redeploying this damaged SAW, but only if they've got some confidence - based on real data, not just gut feelings - that it will work and not make the situation worse.

bobthemonkey · « **Reply #22 on:** 10/30/2007 06:03 pm »

wannamoonbase, the array is designed for on-orbit replacement. The problem is that a flight spare does not exist and would be a major task to complete the replacement. Even if it did, it would not be light, and would need some work on the manifest.

Jorge · « **Reply #23 on:** 10/30/2007 06:05 pm »

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rdale - 30/10/2007 1:58 PM

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Lee Jay - 30/10/2007 1:57 PM

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rdale - 30/10/2007 11:53 AM

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ckiki lwai - 30/10/2007 1:33 PM

Or do they have to do repairs to the shuttle because there was a MMOD hit?

Stop the presses! When / where was a MMOD hit? What sort of damage did it cause?

The press already ran, and the article is on the front page.

Help me out here -- all I see is that they had indications of a possible MMOD strike... Nothing about any damage that needs repair, let alone even confirming it was MMOD. "Likely" does not mean "100%" -- anyone watching the weather forecasts should know that :cool:

No confirmation possible at this time. All they have is a 2.7 g indication on one WLES sensor, could be an impact, could be something else. No one knows, and no one will know until Late Inspection. Speculation is pointless.

rdale · « **Reply #24 on:** 10/30/2007 06:11 pm »

Thanks - I'm at work so not getting as much NASATV time as desired, so I'm not sure if reports of MMOD damage requiring repair would be coming from a WAG or someone in the know. Might need to start using the "ignore" feature...

NYC777 · « **Reply #25 on:** 10/30/2007 07:42 pm »

My gues for the Solar Array repair...extend the mission by another day or tw to support a 6th EVA specifically to repair the Array. I thnik that they'll do a partial retract so that EVs can get up to to the problem area to cut the guide wire or to release the hang up. That's my opinion but let's see what these guys come up with in the next day or so.

rdale · « **Reply #26 on:** 10/30/2007 07:54 pm »

Did you watch the press conference?

kraisee · « **Reply #27 on:** 10/30/2007 08:38 pm »

I have to say, these array problems and SARJ issues are actually very valuable in some ways. These events, and many others, are all helping build an astonishing library of do's and don'ts which NASA will be able to call upon for decades to come.

These incidents will help refine the design of similar systems on future hardware and serve as an incredibly dynamic test-bed for the space engineering community.

I am always impressed with the vast amount of pure data and knowledge which NASA seems to be able to extract from such events, and am always further impressed by the understanding these guys and gals have to be able to work around such issues and typically continue truckin' unhindered after such events.

As an engineer myself, this work is just fascinating to watch.

Ross.

Jorge · « **Reply #28 on:** 10/30/2007 08:49 pm »

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NYC777 - 30/10/2007 3:42 PM

My gues for the Solar Array repair...extend the mission by another day or tw to support a 6th EVA specifically to repair the Array. I thnik that they'll do a partial retract so that EVs can get up to to the problem area to cut the guide wire or to release the hang up. That's my opinion but let's see what these guys come up with in the next day or so.

Cutting the guide wire would be a big mistake.

JimO · « **Reply #29 on:** 10/30/2007 08:51 pm »

SA access and repair?

Sounds also like a good opportunity for a third crewmember out on EVA.

Remember, we've done it once already.

HIPAR · « **Reply #30 on:** 10/30/2007 08:51 pm »

Will the array still generate power with the tear being there? If so can they just use it as is?

--- CHAS

nathan.moeller · « **Reply #31 on:** 10/30/2007 08:53 pm »

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HIPAR - 30/10/2007 4:51 PM

Will the array still generate power with the tear being there? If so can they just use it as is?

--- CHAS

The array is operating at 97% of full power since the electrical wires are intact. Some of the solar cells are shot but it's okay. Like Suffredini said...it's there for power...not to look pretty.

psloss · « **Reply #32 on:** 10/30/2007 08:59 pm »

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HIPAR - 30/10/2007 5:51 PM

Will the array still generate power with the tear being there? If so can they just use it as is?

As Nathan wrote, it is generating power; as was noted in the status briefing, one of the problems with leaving it "as-is" is structural. The system can't be operated normally in the current configuration for things like SARJ rotation, which reduces the amount of power the port-side arrays would be able to generate.

Edit -- JimO's recent post also notes other issues touched on in the briefing:
http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=10531&posts=655#M205344

nathan.moeller · « **Reply #33 on:** 10/31/2007 12:15 am »

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psloss - 30/10/2007 4:59 PM

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HIPAR - 30/10/2007 5:51 PM

Will the array still generate power with the tear being there? If so can they just use it as is?

As Nathan wrote, it is generating power; as was noted in the status briefing, one of the problems with leaving it "as-is" is structural. The system can't be operated normally in the current configuration for things like SARJ rotation, which reduces the amount of power the port-side arrays would be able to generate.

Edit -- JimO's recent post also notes other issues touched on in the briefing:
http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=10531&posts=655#M205344

Correct. The mast can only retain about 10% of its structural integrity when not fully deployed (depending on how far out it is). But you certainly can't rotate the SARJ if that sucker isn't fully extended. That's the big problem right now. They can rotate the BGAs (beta-gimbal assemblies) to track the sun but that's still a severe power shortfall. It's an issue that needs to be worked out and soon. Columbus and Kibo need that power, even if they're just sitting there.

ehartwell · « **Reply #34 on:** 10/31/2007 12:22 am »

[big]Tear on dotted line?[/big]

Medium-high resolution photos have been posted: http://spaceflight.nasa.gov/gallery/images/shuttle/sts-120/flightday08/ndxpage1.html

Here's a closeup of the tear. This looks like the kind of thing duct tape was invented for.

It's hard to tell for sure, but what looks like a small box at the top is probably just the strap material folded back.

nathan.moeller · « **Reply #35 on:** 10/31/2007 12:24 am »

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ehartwell - 30/10/2007 8:22 PM

[big]Tear on dotted line?[/big]

Medium-high resolution photos have been posted: http://spaceflight.nasa.gov/gallery/images/shuttle/sts-120/flightday08/ndxpage1.html

Here's a closeup of the tear. This looks like the kind of thing duct tape was invented for.

It's hard to tell for sure, but what looks like a small box at the top is probably just the strap material folded back.

Wow thanks! Great shot. It looks almost as if it came 'unzipped,' if you will. Now, probably a stupid question, but assuming an EVA crewmember could access the site, could the tear actually be fixed? Or will it have to be left as-is or replaced to deploy the array?

Jim · « **Reply #36 on:** 10/31/2007 12:33 am »

duct tape

Andrewwski · « **Reply #37 on:** 10/31/2007 12:35 am »

You know, I didn't want to mention it when I first saw the tear, but I have to say duct tape was the first thing that popped into my mind...

shuttle_buff · « **Reply #38 on:** 10/31/2007 12:41 am »

I really think Boeing has some responsiblity here. They built the solar array and they know how it should work. If you asked me (with 25 years in the military business) who needs to address this it's Boeing. It's not NASA.

Avron · « **Reply #39 on:** 10/31/2007 12:46 am »

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shuttle_buff - 30/10/2007 9:41 PM

I really think Boeing has some responsiblity here. They built the solar array and they know how it should work. If you asked me (with 25 years in the military business) who needs to address this it's Boeing. It's not NASA.

Good thing Raytheon or LMT was in involved...