WASHINGTON — According to the New York Times, the expanding International Space Station has living space, a science laboratory, storage modules and solar power panels. Now it will get a backbone.
The space shuttle Atlantis is to take off for the station on Thursday with a huge truss crammed into its cargo bay. The goal of this 11-day mission is to attach the central part of what will eventually become a 356-foot support beam for the station.
The truss, 44 feet long and 15 feet wide, is made up of metal crossbars and filled with wiring, pipes, computers and other equipment. It is to be attached to the station during four spacewalks by the seven-member crew.
The astronauts will also attach a mobile transport platform to tracks atop the 27,000-pound truss, the first part of a 300-foot-long mini-railroad that will carry a robotic arm and crew members back and forth across the station on future construction and repair jobs.
Atlantis’s 25th flight will be the first in the 21-year history of the shuttle program for which the National Aeronautics and Space Administration will delay announcing the precise launching time for a civilian mission. Citing heightened security since Sept. 11, the agency said that liftoff would occur between 2 and 6 p.m., and that it would not announce the official time until 24 hours before the flight.
Under the new security plan, an addition to measures already put in effect, NASA will delay an announcement about the arrival of the crew at at the Kennedy Space Center in Florida from Houston until its planes have landed. Astronauts’ activities and locations on the day of the flight will be withheld until three hours before liftoff.
“NASA feels you have to do something about security, and this is the policy that has come from senior management,” said a spokeswoman, Lisa Malone.
Before launching, NASA must also determine that the 58-foot Canadian-built robot arm attached to the station is operating properly, since it will be critical in installing the truss. The multijointed Canadarm2, as it is called, was installed last April and has since experienced periodic problems. In some operations recently, the brake on one of the arm’s seven joints has not released properly, causing it to malfunction.
To work around the problem, Canadian engineers wrote new computer software operating the arm with six joints. The three-member resident crew at the station is testing the new operating procedures for installing the truss. If the software patch fails, the mission could be delayed several days until the problems are worked out, said Michael Suffredini, a NASA station manager.
To fix the problem permanently, NASA decided recently to delay the next shuttle mission to the station to May 31 from May 6 so engineers could add a replacement joint. The astronauts will need time to train for the spacewalk for that operation. The delay also means that the current crew — Yuri I. Onufrienko, the commander, from Russia, and Col. Carl E. Walz of the Air Force and Capt. Daniel W. Bursch of the Navy, both American — must spend an extra month in space.
Adding the center truss element begins a new phase for the $60 billion station, a 16-nation project led by the United States in cooperation with Russia, Japan, Canada and members of the European Space Agency. Over the next two years, six other girder sections will be added to serve as the home for four giant solar power arrays, heat radiators and other equipment that must be in place before attaching science modules from other nations.
The truss, made by the Boeing Company, is a complex piece of equipment with 475,000 parts. It is a lattice of steel and aluminum struts that contains electronics, power and data cables, a television system for viewing outside work, external lights and four global positioning antennas for tracking the station’s location.
Dr. Ellen Ochoa, a veteran of three previous shuttle missions, will used Canadarm2 to remove the truss from the shuttle’s cargo bay and put it on the American-made Destiny science module, where it will be secured by temporary clasps to support beams. Then two spacewalkers — Steven L. Smith, making his fourth flight, and Lt. Col. Rex J. Walheim of the Air Force, making his first — will hook up power and data cables and bolt two forward struts that will permanently hold the truss in place.
In a second spacewalk, two astronauts are to connect more cables and bolt down two aft support struts. They are Jerry L. Ross, 54, a retired Air Force colonel, and Capt. Lee M. E. Morin, 49, of the Navy. Their crewmates call them “the silver team” because they are the first pair of grandfathers to work together outside a spacecraft.
This flight is Mr. Ross’s seventh, a record for shuttle astronauts, and his two scheduled spacewalks will be his eighth and ninth, another record. “I don’t see it so much as a mark in history as just another opportunity for me to go do something I thoroughly enjoy,” he said, acknowledging that this might be his last trip, given that 60 NASA astronauts have not yet flown.
On the last two spacewalks, the teams are to route more cables, install a beam between the truss and an airlock, add lights and install the mobile transporter platform onto twin rails running about 80 inches apart atop the truss. The transporter is a 1,950-pound wheeled structure that will travel along the truss carrying another piece of equipment to be installed on another flight.
This system will eventually allow Canadarm2 to travel the length of the station with loads up to 46,000 pounds. During the mission, astronauts will test the aluminum transporter, 9 feet by 8 feet, by using its dual electric motors to run it up and down the initial 43-foot section of track.
Engineers said the transporter was built not for speed but for smooth operation: it is made to move no more than an inch per second.
Atlantis is to remain docked to the station for eight days. Its crew will also deliver supplies and conduct scientific experiments.
At the end of the operations, Lt. Col. Michael J. Bloomfield of the Air Force, the mission commander who is a veteran of two previous shuttle flights, and the mission pilot, Cmdr. Stephen N. Frick of the Navy, making his first space flight, will guide Atlantis on the two-day trip home. The shuttle is to return to the Kennedy Space Center on April 15.