Ozone Monitor Aboard Space Shuttle Atlantis Fails
They cooled it down, then warmed it up. They turned it off and on, again and again. Nothing worked--a German ozone monitor flying on the space shuttle Atlantis refused to collect data despite ground controllers’ coaxing.
Researchers were not giving up, but they held out little hope Saturday.
“Realistically speaking, we feel that there is very little chance of obtaining any more science data,” said Gerd Hartmann, a German scientist in charge of the experiment.
All the other atmospheric and solar-energy monitors aboard Atlantis, as well as those on a satellite released by the astronauts, were working well.
The problem with the ozone instrument began Friday when the data link between it and ground controllers was lost, apparently because of a computer malfunction. The monitor had worked fine when it was turned on Thursday, just hours after Atlantis rocketed into its 190-mile-high orbit, and collected six hours of high-quality data.
A sudden surge of current in the instrument’s electronics may have burned out one or more components, Hartmann said.
Controllers at NASA’s Marshall Space Flight Center in Huntsville, Ala., turned the monitor off for 1 1/2 hours while it was facing away from the sun to cool the system and get it working. When that failed, they turned the instrument off while it was facing the sun to heat the system. That didn’t work either.
More of the same was planned. There was little else controllers could do because they could not communicate with the monitor’s computer, Hartmann said.
This is the third time in 2 1/2 years that the ozone monitor has flown on a space shuttle.
The instrument was supposed to measure the distribution of water vapor, chlorine monoxide and ozone between 12 miles and 60 miles high. It has a dish-shaped antenna to scan Earth’s horizon.
Chlorine monoxide is formed in the atmosphere by the breakdown of chlorofluorocarbons, which are used in refrigerators and air conditioners and are a leading cause of ozone loss. Major industrial nations have agreed to eliminate these chemicals by the end of the decade.
The thin, invisible layer of ozone in the stratosphere protects against dangerous ultraviolet rays, which can cause skin cancer and cataracts and weaken immune systems.
The defective instrument is not the only ozone gauge flying on Atlantis during its 11-day mission. Ozone is also being analyzed by telescopes aboard the satellite dropped off by the astronauts Friday.
None of these other instruments, however, measures chlorine monoxide.
“That is one piece of the puzzle that we would like to have,” NASA mission scientist Tim Miller said. “So we are disappointed.”
After one day of free flight, the satellite’s infrared telescopes had recorded more than 2 million spectra, or wavelength images. Scientists hope to collect as many as 10 million images before the six-member shuttle crew captures the satellite next Saturday for the trip home.
The mission is due to end Nov. 14.
