Tuesday, August 13, 2019 1:00 am
Satellite cam issue tied to coolant clog
Locally made imager overheating
BRIAN FRANCISCO | The Journal Gazette
Federal agencies have concluded that a coolant system blockage prevented a weather satellite camera built in Fort Wayne from operating at full performance capacity.
NASA and the National Oceanic and Atmospheric Administration recently released the findings of an investigation into why the Advanced Baseline Imager aboard the Geostationary Operational Environmental Satellite 17 had been overheating and temporarily shutting down its infrared channels. Produced by the Harris Corp. plant at Lima and Cook roads, the imager is the main instrument on the GOES-17.
The agencies' report confirmed what officials had publicly suspected for some time: that “the most likely technical explanation for the failure” of the imager was the obstruction of two loop heat pipes “by particles contained in the working fluid.”
An investigative board found that although the pipes were required to carry 390 watts of heat load, they instead carried only 60 watts initially and 10 to 20 watts soon after.
The board said the trouble “could not conclusively be isolated to a specific part or failure” because the satellite hardware cannot be inspected while in space.
Imager coolant problems developed in the weeks after the GOES-17 was launched in March 2018. Two teams of troubleshooters began conducting meetings in Fort Wayne to find causes and identify solutions, according to the report released this month by NASA and NOAA.
An “optimization” team was “able to define alternative operations, procedures and hardware operating limits,” boosting imager performance to 97% of its ability, the report stated. The GOES-17 became operational as GOES West on Feb. 12 to collect weather data over the western United States and the eastern Pacific Ocean.
The report said the estimated direct cost of the glitch amounted to 3% of the $100 million cost of the imager, or $3 million. Costs are among factors that determine the severity of “mishaps” investigated by NASA. The GOES-17 was classified as a Type A Mishap, the most severe among five classifications.
The investigative board recommended that for future GOES projects, contractors review and evaluate satellite design and components; devise cleaning procedures to ensure that particulate levels of working fluids meet contamination requirements; and identify and improve components of a flight system that might be capable of shedding particles.
Pam Sullivan, a satellite flight program manager for NOAA, told The Journal Gazette in February that the particles impeding coolant flow on the GOES-17 appeared to have been from a metal component of the loop heat pipes. She said at the time that contractors were redesigning satellite cooling systems by switching the coolant from propylene to ammonia, eliminating filters and changing the coolant flow course.
NOAA seems satisfied with the Harris imager's current performance. In its announcement of the investigation findings, the agency said the GOES-17 “is providing faster, more accurate, and more detailed observations used by NOAA National Weather Service forecasters to predict Pacific storm systems, severe storms, fog, wildfires and other environmental dangers.”