Spaceflight Now | Breaking News | Station spacewalk begins

Spaceflight Now +

		Subscribe to Spaceflight Now Plus for access to our extensive video collections! How do I sign up? Video archive STS-98: Destiny lab NASA's centerpiece module of the International Space Station -- the U.S. science laboratory Destiny -- rode to orbit aboard Atlantis in February 2001. Play \| X-Large Earth science update NASA leaders discuss the agency's Earth science program and preview major activities planned for 2008, including the launch of three new satellites. Part 1 \| Part 2 STS-97: ISS gets wings Mounting the P6 power truss to the station and unfurling its two solar wings were the tasks for Endeavour's STS-97 mission. Play \| X-Large STS-92: ISS construction The Discovery crew gives the station a new docking port and the box-like Z1 truss equipped with gyroscopes and a communications antenna. Play \| X-Large Expedition 17 crew Pre-flight news briefing with the crew members to serve aboard the space station during various stages of Expedition 17. Play STS-106: Making the station a home in space Following the Russian Zvezda service module's long-awaited launch to serve as the station's living quarters, Atlantis pays a visit in September 2000 to prepare the complex for arrival of the first resident crew. Play \| X-Large STS-101: ISS service call An impromptu maintenance mission to the new space station was flown by Atlantis in May 2000. The astronauts narrate their mission highlights. Play \| X-Large STS-96: First ISS docking The first shuttle mission to dock with the fledgling International Space Station came in May 1999 when Discovery linked up with the two-module orbiting outpost. The STS-96 crew tells story of the mission. Play \| X-Large STS-88: Building the ISS Construction of the International Space Station commenced with Russia's Zarya module launching aboard a Proton rocket and shuttle Endeavour bringing up the American Unity connecting hub. STS-88 crew narrates highlights from the historic first steps in building the outpost. Play \| X-Large Become a subscriber More video

Station spacewalk begins
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: January 30, 2008

Floating in the international space station's Quest airlock module, commander Peggy Whitson and flight engineer Dan Tani switched their spacesuits to battery power at 4:56 a.m. today - 24 minutes ahead of schedule - to officially kick off a planned six-and-a-half-hour spacewalk. The primary goal of the excursion is to replace a faulty solar array positioning motor to improve electrical generation and clear the way for attachment of European and Japanese research modules.

This is the 101st spacewalk devoted to space station assembly and maintenance since construction began in 1998. For identification, Whitson, call sign EV-1, is wearing a spacesuit with solid red stripes around the legs while Tani's suit (EV-2) features broken stripes.

Today's spacewalk is a bit riskier than usual for two reasons: A mistake managing the latches that hold the motor and its housing in place could result in the solar panel's inadvertent release; and because of the shock hazard associated with unplugging and replugging power cables that route 160-volt electricity from the array into the station. To eliminate any chance of a potentially fatal shock, the work will take place when the station is in Earth's shadow and the arrays are not generating any significant power.

"The choreography for the EVA will be very complex, both on orbit and with the ground," Tani said. "Because we're dealing with a solar array that produces kilowatts of power, we have to be very conscientious of when we're going to be opening connections that will expose us to that power. So the bulk of the activities will have to be performed at night when the solar array is not producing any power, or much power, at all."

The bearing motor roll ring module, or BMRRM (pronounced "broom"), is roughly the size of a beer keg and weighs more than 200 pounds. Replacing it is complicated, Whitson said, "because it's really the guts of what's holding the solar array in place. And so Dan and I will have to coordinate when we release and grapple onto the (motor housing) canister in order not to lose the solar array. That would lose us a whole lot of style points!"

Here is an updated timeline of events, including when live television from the station is possible (in EST; times approximate; NOTE: the first minute of each eclipse period, and the last two minutes, are not usable because of residual power generation):


04:56 AM...Spacewalk begins
05:12 AM...ISS TV downlink window opens
05:49 AM...ISS TV downlink window closes
06:10 AM...ISS TV downlink window opens
06:22 AM...ISS TV downlink window closes
06:47 AM...ISS TV downlink window opens
06:52 AM...ISS enters eclipse
07:00 AM...Failed BMRRM removal begins in eclipse
07:27 AM...ISS enters sunlight
07:35 AM...ISS TV downlink window closes
08:24 AM...ISS TV downlink window opens
08:25 AM...ISS enters eclipse
08:30 AM...New BMRRM installation begins in eclipse
09:00 AM...ISS enters sunlight
09:10 AM...ISS TV downlink window closes
09:55 AM...ISS enters eclipse
10:00 AM...ISS TV downlink window opens
10:05 AM...Solar alpha rotary joint inspection begins
10:30 AM...ISS enters sunlight
11:20 AM...ISS TV downlink window closes
11:26 AM...Spacewalk ends (time approximate)
11:30 AM...ISS enters eclipse
11:35 AM...ISS TV downlink window opens
12:05 PM...ISS enters sunlight
12:59 PM...ISS TV downlink window closes