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View Full Version : Solar wing is ripped on space station..


Waterbuffalo
10-30-2007, 11:22 PM
Find it here: http://news.yahoo.com/s/ap/20071031/ap_on_sc/space_shuttle_217

By MARCIA DUNN, AP Aerospace Writer 43 minutes ago

CAPE CANAVERAL, Fla. - A giant solar wing ripped as it was being unfurled by astronauts aboard the international space station on Tuesday, creating another problem for NASA at the orbiting outpost.

The next shuttle flight could be delayed if this latest problem isn't resolved quickly, said NASA's space station program manager, Mike Suffredini. Atlantis is supposed to lift off in early December with a European laboratory.

"We don't clearly know what we're dealing with yet, and as soon as we know what we're dealing with, then we can talk about what our next steps are," Suffredini said.

The astronauts immediately halted the wing extension when they spotted the damage. By then, the solar panel was already extended 90 feet of its 115 feet. Space station commander Peggy Whitson said the sun angle prevented her and the others from seeing the 2 1/2-foot tear sooner.

"It's just the way it goes," Mission Control said consolingly.

The torn solar wing can still provide power. NASA's bigger concern is the structural problem posed by a partially deployed panel.

The damage was especially agonizing for the 10 space travelers because it came on the heels of an otherwise hugely successful day. Two of shuttle Discovery's crew had just wrapped up a seven-hour spacewalk and were still reveling in the smooth extension of the first of two retracted solar wings on a newly installed beam.

During the spacewalk — the third of their mission — Scott Parazynski and Douglas Wheelock installed a massive beam holding a pair of solar wings, which were folded up like an accordion. It took three days to move the beam from one location on the space station to another 145 feet away and was considered one of the hardest construction jobs ever attempted in orbit.

Parazynski also dealt with the other problem on the space station, inspecting one of two rotary joints that keep the station's solar panels turned toward the sun.

Steel shavings were found during a spacewalk over the weekend in the joint on the right side of the station, and Parazynski was asked to look at the left joint for comparison. Everything inside that joint was shiny and looked pristine.

Until NASA figures out what's grinding inside the gears and fixes it, the right joint will remain in a parked position as much as possible, limiting power collection.

Astronauts awoke Wednesday to the sounds of "Nel Blu Dipinto di Blu" ("In the Blue Painted Blue"), more commonly known as "Volare."

"Thank you for giving us a song that we can sing all day," Shannon Lucid told Italian astronaut Paolo A. Nespoli.

NASA plans to take a closer look at the malfunctioning joint during a spacewalk on Thursday, although that work might be upstaged by the solar wing trouble.

At Mission Control's request, Whitson retracted the torn solar wing just a bit to ease tension on it. She said there appeared to be quite a lot of deformation to the entire area, with several sections bowed backward and kinked in various places.

The astronauts beamed down pictures of the damage so engineers could determine how bad it was and what, if anything, could be done about it.

Suffredini said the wing can provide 97 percent power since the power line doesn't appear to be damaged. He said spacewalking astronauts could cut whatever might be snagging the solar wing, like a hinge, and possibly sew up the tear. For almost any repair, the wing probably would have to be retracted in order for the crew to reach the damage.

"We have a lot of options. We're in a good config (configuration) to sit here and work through this problem," he said.

Discovery's space station construction mission has already been extended a day because of the solar joint problem, with landing set for next Wednesday. Suffredini hinted that another two days could be added to the flight if the newest problem is deemed serious enough.

___

On the Net: NASA: http://spaceflight.nasa.gov

Chief
11-03-2007, 05:59 AM
The repair for this tear is underway right now, and I'm watching live coverage on NASA TV.

Fascinating stuff! The crew has made a series of "cufflinks" from wire and aluminum strips, that are being installed around the damage, to take the strain off of the damaged area, and allow the solar panel to be completely deployed. It's avery tricky operation, becasue of the tight clearances between the astonaut and th solar panels, which are still generating electricity. Each one of the infividual panels on the solar array generates about 800 watts of power, and distributes it to the edges of the array. The further down the array you go, the higher the cumulative power generated. There is no way to turn the array off. If sunlight hits it, it generates power...

This operation is being carried out on the end of the "boom" that is used to inspect the shurrle's tiles in orbit. The boom is mounted on the end of the shuttle's robotic arm and it is very tricky to maneuver the 'naut around 10 centimeters at a time.

Chief
11-03-2007, 06:39 AM
Amazing! Like I said, the MS is working off of the end of the boom, which is being held by the robotic arm; but what doest that mean?

Take a broomstick, and hold it in your hand at the middle of the stick. The stick is the boom, and your hand is the articulated wrist at the end of the Canadian shuttle arm. Your elbow is fully articulated, as is hour shoulder. Each segment is 50 or so feet in length, with an astronaut on the end of it all.

Houston is controlling the movement of the arm, becasue they have a virtual space station in their computers, and are able to control the motion to the millimeter. What makes it tricky is that they are working on the outer 1/3 of a partially deployed and very large active solar array, that is very delicate by nature. The straighter the arm is, the less accurate the control becomes, because you start getting "dynamic" changes in direction during movement becasue of all the articulated joints, that are hard to predict. They end up doing manual adustmenst on the fly so the guy on the boom can reach everything he needs to without getting electrocuted in the process.

I've seen video of these solar panels being test deployed on the ground. They are designed to be opened in a weightless environment and cannot support it's own weight on earth. The test rig to deploy these panels is pretty complex and simulates zero G. I don't think they have figured out exactly what caused the damage either. I guess it could have been done during launch during maximum G's, but who knwos for sure?

Chief
11-03-2007, 09:56 AM
This repair worked like a charm. Very impressive to be able to watch this live this morning over coffee...

;D

Waterbuffalo
11-03-2007, 01:43 PM
Chief, you know what I wish?

There was a media source or show of really interesting, weird, or fascinating science projects and how they are solved. Kind of like a Ripley's Believe it or not mixed with national geographic special..

This would be an interesting idea!

Chief
11-03-2007, 05:19 PM
If there was, this repair would qualify. I was very impressed with the innovative solutions they came up with, how carefully they prepared everything, and how perfectly it all worked. The video was incredible, with some pretty stunning views looking down the length of the robotic arm, past the ISS to the earth spinning by 200 miles below.

It's a long way down....

;D

Waterbuffalo
11-04-2007, 08:25 PM
Are you saying near the end of your comments they were trying to recreate the Skylab downing?

Chief
11-04-2007, 09:44 PM
No, I was reflecting on the view...some pretty stunning video...