Astronaut-Electricians Succeed in Getting Data To Ground
Astronaut-Electricians Succeed in Getting Data To Ground
May. 05, 1991
CAPE CANAVERAL, Fla. (AP) _ Discovery's astronauts succeeded in getting data from three scientific instruments to the ground Saturday after splicing wires and rearranging cables in a 97-step salvage operation.
It was a desperate, final attempt to retrieve information from the instruments, which became virtually useless after their data recorders failed shortly after launch a week ago. Controllers now hope to obtain about half of what the investigators initially sought in what remains of the flight.
The ''Star Wars'' research mission is due to end Monday.
''By God, we put it together and it's working great,'' said Air Force Capt. Lindley Johnson, a program director. ''We're getting excellent data.''
Johnson said there were a few minor problems still to be resolved, including getting used to the periodic loss of radio contact.
''That's an operational constraint that we have to live with. We have to plan around those gaps in the coverage,'' he said.
Mission Control's Jan Davis informed the seven astronauts of the strong link between the space shuttle and ground about 2 1/2 hours into the electrical repairs.
''Good work, guys,'' she said. ''That was a super job.''
The work involved rerouting data from the instruments through a flight deck computer panel, through 20 feet of TV cable, through an antenna, through a satellite to the ground.
''It is one of the more involved things we've ever tried to do,'' NASA flight director Bob Castle said.
The link bypassed the two data recorders, which mysteriously stopped working just hours after Discovery blasted off last Sunday into an orbit 161 miles above Earth. Numerous repair attempts failed.
Johnson said it appears as though a contact on a connector for joining ground test equipment to the recorders grounded out, causing the tapes to wind off their reels.
A hastily organized team of engineers and scientists came up with the data- rerouting plan Friday. The astronauts got started on it Saturday morning after all seven were awake. Normally, they are splitting 12-hour work shifts in orbit.
As one astronaut pointed a flashlight into the dark confines of the computer panel, stuffed with bundles of cables, another crewman in goggles snipped the designated wire. One of the astronauts then scraped off the wire's coating and spliced it to two jumper leads.
Video beamed down from Discovery provided close-up views of the work being performed by pilot L. Blaine Hammond Jr. and Donald McMonagle.
''We thought there might be another crew member on board with as many hands as we saw on there,'' Davis later told the astronauts.
Hammond and McMonagle connected the jumper leads to 20 feet of TV cable, then extended the cable from the flight deck to the middeck one level below. The free end of the cable was linked into the system for the shuttle's main antenna.
To see if it worked, data from the instruments were sent to the antenna. The antenna, in turn, transmitted the signals via satellite to NASA receivers at White Sands Test Facility in New Mexico.
''Tell the people they did a super job of working up that procedure,'' shuttle commander Michael Coats told Davis.
Provided the link remains strong, controllers expect to collect about 4 hours worth of high-priority data from an X-ray detector that had been crippled by the recorder failure. Before trouble struck, scientists had originally planned to collect about 10 hours worth of information, said NASA flight director Rob Kelso.
The principal investigator for that instrument, Ed Fenimore, said before the repair that he would be satisfied with half.
''It's going to be worth more than we thought because our detectors are working better,'' said Fenimore, an astrophysicist at Los Alamos National Laboratory in New Mexico. ''We are more effective at seeing the X-rays than we thought we were.''
But the X-ray detector automatically turned off Saturday night after apparently overheating. Ground controllers decided not to operate the instrument again during the flight after determining there was a problem with its power supply. Several observations were missed as the astronauts and ground teams tried to get the instrument working again.
Fenimore lost at least six experiments early in the mission as a result of the recorder trouble. Most of his observations had been scheduled for this weekend.
He is conducting the experiments for the Energy Department, which wants celestial X-ray readings to differentiate between natural and nuclear sources of X-rays. The findings could help verify whether nuclear test treaties are being observed.
Also hindered by the recorder failure were an instrument to study the horizon in ultraviolet wavelengths and a contamination-measuring device. Two other instruments constituting the Defense Department payload have their own data-collecting devices and were unaffected.
The set of five instruments is valued at $160 million.
The Pentagon also has a $94 million infrared probe aboard Discovery. The probe spent 1 1/2 days in orbit studying the shuttle's engine exhaust plumes for the Strategic Defense Initiative, known as ''Star Wars.''
Pentagon officials ordered the experiments to gather information needed to develop sensors for tracking and destroying enemy missiles. Findings from the plumes and atmospheric light, or aurora, will be secret, unlike most mission information.
Kelso said all scientific observations will be halted late Sunday night so the astronauts can start getting ready to come home. Discovery is scheduled to land Monday afternoon at Edwards Air Force Base, Calif.