WASHINGTON — Engineers have made some progress in restoring performance to the key instrument of a weather satellite launched earlier this year, but have yet to fully fix the problem or determine its root cause, the National Oceanic said. and Atmospheric Administration on July 24.
In a conference call with reporters, NOAA officials said they were able to improve the availability of infrared and near-infrared channels on the GOES satellite’s Advanced Baseline Imager (ABI) instrument. -17 since the agency first reported the issue two months ago. The spacecraft, initially known as GOES-S, launched in March.
“ABI is already demonstrating improved performance over what was initially observed,” said Pam Sullivan, GOES-R System Program Manager. Currently, 13 of the instrument’s 16 channels are available 24 hours a day, with the other three capable of operating at least 20 hours a day.
This will change, however, on a seasonal basis, depending on how much sunlight shines into the instrument. By September, the hottest part of orbit, only 10 of the 16 channels will be available 24 hours a day, she said, with the other six being available “most of the day”.
While one team works to improve ABI performance on GOES-17, another team searches for the instrument’s root cause. Sullivan said the issue appears to be related to looped heat pipes containing propylene coolant. “It doesn’t seem to flow through curls properly,” she said.
She said the team had identified a “small handful” of probable causes for the lack of coolant flow. They include “excess non-condensable gas” or foreign material debris in the pipes. “Either could prevent fluid from flowing through the looped heat pipe as intended,” she said. There could also be mechanical damage to the pipes.
When NOAA first announced the problem with the ABI on GOES-17 in May, the agency said it had not seen a similar problem with an identical instrument on GOES-16, the first of the GOES-R series of next-generation weather satellites launched. in 2016. However, Sullivan said that since then engineers have seen “evidence of reduced functionality” in that spacecraft’s ABI loop heat pipes, but that has not affected the performance of the spacecraft. instrument.
Sullivan said that in the case of GOES-16, the problem existed from the start of the mission but was only noticed when engineers took a closer look at the instrument’s performance. “There is no sign at this stage that GOES-16 performance is changing now,” she said.
NOAA still plans to put GOES-17 into service later this year as GOES-West at 137 degrees west, replacing GOES-15 in that orbital slot. “Even during this verification phase, GOES-17 is observing with more channels and higher resolution with faster refresh than what we currently have with the current GOES-West satellite,” Sullivan said. “Although we won’t get the full functionality of GOES-17, we will receive more and better data than we currently have.”
NOAA added that it can augment data from other sources, including other GOES satellites as well as Japan’s Himawari satellites, which also have a version of the ABI instrument. The National Weather Service does not expect this issue to have any effect on its ability to produce weather forecasts.
“Right now we have an operational constellation,” said Joe Pica, director of the National Weather Service’s Office of Observations. “We are able to carry out our mission today without any degradation.”
The issue, however, could delay the launch of the next satellite in the series, GOES-T, currently scheduled for 2020. “We haven’t given up on that yet,” Sullivan said of that planned launch date. “However, we really need to decide what modifications and tests we want to do on the GOES-T instruments before confirming these dates.”
“There is no doubt that the issues we are having with the cooling system are disappointing, and not what we expected from GOES-17 when we launched,” said Steve Volz, Director of Satellite Service and Operations. information from NOAA. “But we are committed to doing it right. We will understand what happened on GOES-17 so that it does not happen again on our other GOES satellites.