Miles O'Brien on Endeavour's mission

CNN Space Correspondent Miles O'Brien is monitoring the latest mission of the space shuttle Endeavour.

Q: How important is this mission?

O'BRIEN: This is the most important shuttle mission to the space station to date. If the huge solar arrays inside the cargo bay of Endeavour are not successfully attached and deployed, the International Space Station -- dubbed "Alpha" by its first occupants on the day they moved in -- would be essentially stillborn.

The arrays are capable of producing at peak enough power to keep the lights on, the stereos blaring and the ovens cooking in 30 average homes.

In the short term, this is important for the first crew, NASA astronaut Bill Shepherd and Russian cosmonauts Yuri Gidzenko and Sergei Krikalev. Since they have inhabited the station, they have been unable to access the U.S. side of the outpost. The so-called "Unity" docking node remains sealed, cold and dark.

Shepherd is anxious to get inside Unity -- the muscular, stocky Navy SEAL wants to use Unity as a workout/weight room.

In the long run, the arrays are important for a lot of reasons. For one thing, NASA could not launch the U.S. laboratory Destiny in January, aboard Atlantis as is currently hoped, if these solar arrays are not on line. There simply would not be enough power to turn on the lights.

These arrays -- the largest structures to fly in space ever, and with a wing span of 240 feet -- are the first of four identical sets that are slated to be added to the station during its construction phase over the next six years. But it is safe to say without the power the station will not grow.

Q: What are the solar arrays for? What will be their function?

O'BRIEN: The arrays are truly amazing. NASA gave us a small sample of the wafer-thin solar photo voltaic cells, and they practically crumbled in our hands.

It is hard to believe they will survive the rigors of 15 years in space. There is no doubt they will be damaged by micrometeoroids, but engineers say they are designed so a puncture will not prorogate, or cause a short. So, while the holes will reduce the arrays' ability to produce power, it will be very small and very gradual.

The arrays have a gold sheen to them, and if you know when and where to look -- check spaceflight.nasa.gov for details -- you will be able to spot Alpha streaking overhead just before dawn and just after sunset. They say it will be the third-brightest object in the night sky, after the moon and the star Sirius. I'm not sure how it rates against Venus.

Nothing like this has ever been flown in space, so it will be interesting to see how things go on Sunday. The spacewalkers who will be outside the shuttle during the unfurling will have TV cameras in their helmets.

This is new, and they are apt to capture the event, with the shuttle beneath the arrays and the blue earth below. Should be an amazing picture. Hopefully we can push the chads aside for a spell to get this on the air.

Q: What will the shuttle crew be doing during the space walks?

O'BRIEN: The spacewalkers -- astronauts Carlos Noriega and Joe Tanner -- will spend their first two sojourns aiding the installation of the solar arrays and related gear. Canadian astronaut Marc Garneau and shuttle pilot Mike Bloomfield will operate Endeavour's 50-foot robotic arm.

They will move the 35,000-pound array package from the shuttle cargo bay to its place on Alpha. Because of the way the station and shuttle are oriented, the arm operators will have to do much of their work "blind." They have a computer system that helps. It is called the Space Vision System, but it has been a bit quirky. So Tanner and Noriega will act like members of a moving crew, telling Garneau where the arrays are and guiding it onto its bolts.

Once they pull off that task, they will start plugging in cables. Of course, NASA doesn't want them messing with anything that is hot, so there will be some close coordination between Houston, Moscow and Endeavour to make sure they are safe.

On their second walk (on Tuesday), they will continue plugging in cables and they will move a communication antenna that would be obscured by the unfurled arrays. They will also arrange some hardware so the station is ready to receive the Destiny lab in January.

On the third walk, they will deploy a detector that will measure any static electricity that might be generated as the arrays move through the edge of the atmosphere. There is some concern that area around the arrays might become hazardous to spacewalkers in the future -- possibly creating the risk of a serious shock.

For the station and shuttle crews, this will be a strange visit because the shuttle's cabin atmosphere has to be lowered to protect the spacewalkers from getting the "bends."

The station's atmosphere will remain at 14 psi (pounds per square inch), so the hatches will remain closed until Friday. They will open them up for 24 hours, giving (the crews) precious little time for a face to face visit. Life is tough on the frontier.

Endeavour heads for space station rendezvous
December 1, 2000
Space station astronauts pause to give holiday thanks
November 23, 2000
Blurry camera causes tricky docking at space station
November 18, 2000
A space reporter's trek to the highly remote frontier
November 14, 2000
Space station crew boards new home
November 2, 2000

International Space Station
Boeing: International Space Station
Shuttle Orbiter Endeavour (OV-105)
NASA
Kennedy Space Center

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