Spacewalkers to prep station for new Russian module
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: June 4, 2009
The Endeavour astronauts, wearing bright orange pressure suits, strapped in aboard the shuttle today for a dress-rehearsal countdown that sets the stage for launch June 13 on a space station assembly mission. The station crew, meanwhile, prepared for a spacewalk early Friday, the first of two needed to rig the Russian Zvezda module for attachment of a new docking port.
"I personally have always thought it's a really important, necessary part of what the entire team does," commander Mark Polansky said Wednesday. "It focuses the team, it certainly gets them to look at a lot of things they're going to see on launch day. If there are going to be any glitches, now is the time to find it out.
"From the crew perspective, for some people, they've never, ever gotten up to a vehicle and strapped in one before. So, I think it gives you a certain familiarity that will pay dividends when you do it for real."
Polansky, pilot Douglas Hurley, Canadian flight engineer Julie Payette, David Wolf, Christopher Cassidy, Thomas Marshburn and space station flight engineer Timothy Kopra planned to fly back to Houston late today and to enter medical quarantine Saturday.
If all goes well, the astronauts will fly back to Florida next week for the start of their countdown at 9 a.m. Wednesday. Launch is targeted for 7:17 a.m. June 13.
The primary goals of the five-spacewalk mission are to deliver an external experiment platform that will be attached to the Japanese Kibo module, to deliver critical spare parts and to replace a set of aging solar array batteries. In addition, Kopra will replace Japanese astronaut Koichi Wakata, who will return to Earth aboard Endeavour.
Aboard the space station Thursday, commander Gennady Padalka and NASA flight engineer Michael Barratt prepared for a spacewalk early Friday to install docking system antennas on the upper port of the Russian Zvezda command module. Padalka and Barratt plan a second, internal spacewalk Wednesday to make interior modifications.
A new docking module, known as MRM-2, is scheduled for launch atop a Soyuz rocket on Nov. 10. Once attached to the station, it will add a fourth Russian docking port to support the increased traffic required by a full-time crew of six.
For Friday's five-hour excursion, Padalka, call sign EV-1, will be wearing an upgraded Russian Orlan MK suit with red stripes while Barratt, EV-2, will be wearing a suit with blue stripes. The spacewalk is scheduled to begin around 2:45 a.m. EDT.
This will be the 124th spacewalk devoted to station assembly and maintenance since construction began in 1998, the fifth so far this year, the seventh overall for Padalka and the first for Barratt. Going into Friday's excursion, more than 80 astronauts and cosmonauts representing the United States, Russia, Japan, Canada, Germany, France and Sweden had logged 775 hours of space station EVA time.
The KURS antennas being installed by Padalka and Barratt are passive elements in a system that will enable the MRM-2 docking module to home in on the station, line up and dock at the zenith port of the Zvezda command module.
The station currently has three Russian docking ports: an Earth-facing port on the forward end of the Zarya module and two on Zvezda, one facing Earth and the other at the rear of the lab complex.
At present, two three-seat Soyuz lifeboats are docked at the station, one at Zarya and the other at Zvezda's aft port. An unmanned Progress supply ship is attached to the Pirs docking module on Zvezda's Earth-facing port. The MRM-2 docking module scheduled for launch in November will go on the zenith port directly above and across from Pirs.
Yet another docking module, known as MRM-1, is scheduled for launch next year aboard a space shuttle. It will be attached to Zarya's downward facing port, providing the clearance needed for planned U.S. Orion crew capsules to dock at a downward-facing port in the station's U.S. Unity module.
During the upcoming spacewalks, the station crew will be split up to make sure everyone has access to a Soyuz lifeboat at all times. Wakata will join Barratt and Padalka in the Russian segment of the station, with access to the Soyuz docked at the command module's aft port, while Frank De Winne, Robert Thirsk and Roman Romanenko remain in the forward U.S. segment of the lab, with access to the Soyuz docked to the Zarya module's Earth-facing port. The hatchway between Zarya and Zvezda will be closed.
"The antennas installed on the station are the passive system where the active antenna are on the arriving vehicle," said David Korth, NASA's Expedition 20 spacewalk director. "For this particular EVA, the first set of antennas ... are for range, range-rate and roll misalignment. The second antenna block to be installed (is) a relative attitude measurement antenna.
"So we'll be installing both of these antennas, routing all the cabling externally. Several weeks ago, the crew began performing internal cable routing so at the end of this EVA, these will be functional antennas. In fact, toward the end of the EVA we will be performing a quick continuity check to verify all the signal paths are correct."
At the end of the spacewalk, Barratt will anchor himself to a telescoping Russian crane and Padalka will extend his crewmate up above Zvezda's zenith port. Barratt then will photograph the area to help Russian engineers confirm the new antennas are properly oriented.
"Once he takes the photos, he will come back in," Korth said. "At this point, this is when the Russian ground team will perform the continuity checks of the antennas to make sure everything is wired correctly. And then the crew will head back into the Pirs docking compartment, thus ending EVA-22."
For the spacewalk Wednesday, Gennady and Barratt will remain inside the Zvezda module's forward transfer compartment, sealed off from the rest of the station and working in vacuum while connected to umbilicals. The ball-shaped transfer compartment connects Zvezda to the Zarya module and features upward- and downward-facing hatches. Pirs is attached to the Earth-facing port while the new MRM-2 module will be attached to the zenith port.
The goal of the second EVA on June 10 is to install a docking cone on the zenith port to complete preparations for the new module's arrival in November. The internal spacewalk is expected to last about an hour. A few hours after its conclusion, NASA plans to start Endeavour's countdown to launch.