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 space shuttle Atlantis refused to collect data despite ground controllers' coaxing.
Researchers weren't giving up, but 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.
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.