Harris imager glitch tied to 3 likely causes

July 25, 2018 GMT

Federal scientists have identified the likely causes of a glitch plaguing a weather satellite camera built in Fort Wayne.

And they said Tuesday that the Harris Corp. instrument is working better than when the trouble was detected in the spring.

Harris’ Advanced Baseline Imager “is already demonstrating improved performance from what was initially observed,” Pam Sullivan, a satellite flight program manager for the National Oceanic and Atmospheric Administration, said during a conference call with news media.

The imager is aboard the GOES-17, which was launched March 1. GOES stands for Geostationary Operational Environmental Satellite.

NOAA said in May that an imager cooling system was running warmer than its optimal temperature of minus 350 degrees Fahrenheit. As a result, three of the camera’s 16 channels were working for only part of each day.

Sullivan said Tuesday that an investigative team found that propylene coolant was not flowing as intended through the system’s loop heat pipe for three possible reasons: either excess non-condensable gas or foreign-object debris was inside the pipe, or the pipe has suffered mechanical damage.

Sullivan said ground tests will be conducted in Beltsville, Maryland, by the pipe manufacturer Northrop-Grumman. Those tests are expected to take two or three months, and then imager testing will be done by Harris at its Fort Wayne or Rochester, New York, plants, Sullivan said.

Another team is figuring out how best to operate the weather satellite in its “compromised state,” Steve Volz, director of NOAA’s Satellite and Information Service, told reporters.

“That team has confidence that they can get the ABI operating to a point where GOES-17, including all of its instruments including the ABI, will be a significant sustained valuable contribution to NOAA’s satellite fleet throughout its mission lifetime,” Volz said.

Sullivan said the team had been able to increase available observation time by readjusting light detector and cryocooler temperatures, decreasing detector integration time and changing the satellite’s orientation in space. 

The cooling system malfunction is affecting infrared channels of the camera. Those channels collect data on wind heights and water vapor in Earth’s atmosphere.

During the cooler parts of the year where the GOES-17 is positioned : currently 22,000 miles above the center of the Western Hemisphere : 13 of its 16 camera channels function around the clock, and the other three are available for at least 20 hours a day, Sullivan said.

During warmer periods : the equinoxes in September and April : 10 channels work all of the time and six others work part of the time. The satellite is tilted toward the sun during these seasons and away from it around the solstices in June and September.

“There’s no doubt that the problems we are experiencing with the cooling system are disappointing and not what we expected of GOES-17 when we launched,” Volz said, “but we are committed to getting this right. We will figure out what happened on the 17 so that it doesn’t occur again on our other GOES satellites.”

Sullivan said planned launches of other satellites in 2020 will be delayed if the GOES-17 bug is not found and fixed.

After the media call, Harris communications manager Kristin Jones told The Journal Gazette in an email that the company “has been working closely with NOAA, NASA and other industry experts to improve operation of the ABI instrument. These teams are making great progress and as a result, the ABI is providing better and faster weather data with more channels at a higher resolution today than the current imager, which it will replace later this year.”