NASA analyzes Columbia's sensor recorder

Data from 700 sensors is in this Orbiter Experiment Support System unit, which survived the shuttle's fatal crash.

NASA space shuttle engineers are analyzing the output from a sensor data recorder that survived the Columbia's fatal crash into an East Texas debris field.

The Orbiter Experiment Support System recorded data from about 700 sensors distributed around Columbia, a NASA spokesman said. In all, the data consumes 9,400 feet of 1-inch-wide magnetic tape stored on two 14-inch reels.

The sensors recorded data such as temperature, pressure, vibration, acoustics and strain. The OESS tape device is designed to operate during the space shuttle's liftoff and ascent, then turn off until the spacecraft begins its return journey through the Earth's atmosphere, NASA spokesman James Hartsfield said.

OESS had recorded data on about half the total length of the tape by the time the accident stopped it, Hartsfield said, or about an hour and a half of data. The 28-track tape records data at a rate of 14 inches per second, he said. Different sensors report data at different rates, and the OESS sensors record data that is different from the telemetry the spacecraft sends back to ground controllers.

'It is not a black box,' Hartsfield said, referring to the flight data recorders that aircraft carry to assist in analyzing crashes. 'But it does give valuable data.'

After normal flights, NASA engineers transfer the contents from OESS to a second tape via an umbilical data cable attached to the shuttle. OESS itself remains bolted into the spacecraft during this process, Hartsfield said, and the engineers erase the data on its magnetic tape after they have completed the transfer.

In the case of Columbia, NASA transferred the somewhat damaged OESS to Imation Corp. of Oakdale, Minn., so the company could clean and stabilize the tape.

Imation scientists inspected and evaluated the tape and cleaned it by immersing it by hand in filtered, deionized water, the company explained in a description of the process. After the scientists dried the tape, they respooled it on the original hubs with two new flanges.

Imation sent the tape to Kennedy Space Center in Florida, where NASA engineers made a copy of the tape for transfer to the Johnson Space Center in Houston. They used the same equipment they normally use after a shuttle flight'except the shuttle itself'to create the Columbia tape, Hartsfield said.

NASA engineers at the Houston center loaded the data onto the agency's mainframe there and now are manually analyzing its contents.

The tape output comes largely in the form of graphs that NASA specialists can compare to similar data from other shuttle flights to detect unusual conditions or anomalies, Hartsfield said.

NASA assigned the manual data analysis job to the engineering team that normally evaluates output from OESS after shuttle flights because they will be able to bring their experience into play in detecting the importance of anomalies, Hartsfield said. NASA said the team numbers fewer than 20 people.

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