Spaceflight Now: STS-92 Mission Report

Discovery lifts off on station assembly mission
BY WILLIAM HARWOOD
SPACEFLIGHT NOW

Posted: October 11, 2000

  Discovery
Discovery lifts off its Florida launch pad. Photo: NASA TV/Spaceflight Now
 
After a string of frustrating launch delays, the shuttle Discovery finally rocketed into orbit today to kick off the 100th shuttle mission, the most complex space station assembly flight yet attempted.

With commander Brian Duffy and rookie pilot Pamela Melroy at the controls, Discovery's twin solid-fuel boosters ignited with a crackling roar at 7:17 p.m., instantly pushing the 4.5-million-pound spaceship skyward.

"...three, two, one, booster ignition and liftoff of Discovery, making shuttle history and building our future in space," gushed NASA launch commentator Joel Wells as Discovery roared to life.

Putting on a spectacular sky show, the shuttle majestically climbed above its launch gantry, wheeled about to line up on the proper trajectory and arced away to the northeast, hot on the trail of the international space station.

Launch occurred at the moment Earth's rotation carried pad 39A into the plane of the space station's orbit.

  Discovery
Discovery climbs through the evening sky. Photo: NASA TV/Spaceflight Now
 
The unmanned station complex was sailing 230 miles above the southern Indian Ocean at the moment the shuttle thundered aloft.

It will take Duffy and company two days to chase down their quarry for a carefully choreographed docking Friday afternoon as the two spacecraft pass over Russian ground stations.

Joining Duffy and Melroy aboard the shuttle are Japanese robot arm operator Koichi Wakata and spacewalkers Leroy Chiao, William McArthur, Peter "Jeff" Wisoff and Michael Lopez-Alegria. Melroy is the only rookie on the roster.

"Pam, welcome to space and congratulations," astronaut Dominic Gorie called from mission control in Houston after the shuttle slipped into orbit.

  Walkout
The crew of space shuttle Discovery leave for the launch pad. Photo: NASA/KSC
 
"Thanks, Dom, it was beautiful!" replied Melroy, only the third woman to pilot a space shuttle.

The goal of mission STS-92 is to attach a new $20 million shuttle docking port and a $273 million truss that will serve as the mounting point for a huge set of solar arrays scheduled for deliver in December.

Other equipment on board pushes the total cost of Discovery's payload to around $300 million.

Four back-to-back spacewalks by alternating two-man teams will be required to electrically connect the new components, to hook up coolant lines and to position the station's main KU-band and S-band radio antennas.

With today's on-time liftoff, Discovery will dock with the station around 1:43 p.m. Friday. Wakata then plans to mount the Z1 truss atop the U.S. Unity module around 11:02 a.m. Saturday. The first of the four back-to-back spacewalks is scheduled to begin at 10:32 a.m. Sunday.

If all goes well, Discovery will undock from the station around 9:37 a.m. on Oct. 20 and land back at the Kennedy Space Center at 2:10 p.m. on Oct. 22.

Just eight days later, the space station's first full-time crew - commander William Shepherd, Yuri Gidzenko and Sergei Krikalev - is scheduled for launch aboard a Russian Soyuz rocket.

  PMA-3
Animation shows the black PMA-3 being attached to Unity by the shuttle's robot arm above the nose of Discovery. Photo: NASA TV/Spaceflight Now
 
NASA plans to close out the year by attaching a huge set of electricity producing solar arrays to the station in early December that will ease an on-going power shortage aboard the outpost.

Two of the Russian command module Zvezda's eight batteries are not working properly. While the module can operate in a powered-down mode with as few as three, NASA considers five the bare minimum to support a full-time crew.

Station controllers are discussing the possibility of having Discovery's crew enter the module for an impromptu inspection to gain insight into what might be wrong with batteries 4 and 5.

But he astronauts are not trained to service Zvezda's batteries and there is little they could do beyond inspecting connectors to make sure there are no obvious wiring problems.

Should additional batteries fail between now and the end of the month, station managers likely would re-assess the wisdom of launching Shepherd's crew on Oct. 30 as currently planned.

In that case, NASA managers would consider launching the solar arrays first to provide a more comfortable power margin. But at this point, no such decisions have been made.

NASA originally hoped to launch Discovery last Thursday, but the flight has been repeatedly delayed by technical problems, bad weather and, on Tuesday, because of an oversight by ground crews.

Discovery was already fueled for takeoff Tuesday when an inspection team noticed an eight-ounce metal locking pint lodged in an inaccessible area at the base of the shuttle's external tank.

Such tethered "pip pins" are used to secure tools and access platforms at the pad and it's not yet known how this one made its way onto the external tank. Officials said it should have been spotted earlier, but technicians did not find it until the T-minus three-hour mark.

Worried the pin could fall free during ascent and damage a critical system, shuttle managers reluctantly ordered a 24-hour launch delay so a rotating gantry could be put back in place to give technicians access to the area.

Around 2 a.m. today, technicians finally reached the offending pip pin and removed it, setting the stage for a fifth launch attempt this evening.

If the flight is delayed again for any reason, shuttle managers likely would stand down until Friday to top off the ship's on-board supplies of liquid hydrogen and oxygen, which are used to power the shuttle's electrical generators.

A launch try Thursday would require a flight-day four rendezvous with the space station while launch tries Friday and Saturday would result in dockings on the third day of the mission.

That is NASA's preferred option to maximize the time available to the crew to complete its work.

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Space shuttle Discovery blasts off October 11 on a construction flight to the international space station.
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