A micrometeoroid might be the culprit for an abrupt attitude problem that halted the flow of critical weather prediction data for the East Coast from a (NOAA) satellite, according to a program official.
A Geostationary Operational Environmental Satellite (GOES) stopped sending imaging and sounding data late May 22, prompting the-made satellite to enter into an orbital safe mode. In this mode, the satellite shuts down its instruments and goes into a spin stabilized status, not its typical three-axis stabilization, to await input from operators on the ground.
Because the satellite appears healthy, officials are considering the possibility of an “external disturbance” — a micrometeoroid collision — causing an “attitude disturbance” in the satellite’s orbit 22,300 mi. over the East Coast, says Ron Mahmot, the mission operations division manager for GOES at NOAA.
Boeing officials are conducting a forensic analysis of the satellite’s data to determine from which trajectory the disturbance occurred and what its effect on the satellite could have been.
“The contractor is doing a very good job and is being very methodical,” Mahmot tells Aviation Week, adding that there is no evidence to believe the satellite’s instruments have failed. “We have not validated the work. But we have no reason to think they won’t.”
“Boeing and NOAA engineers are working to resolve the issue in an attempt to restore service as quickly as possible,” says company spokeswoman Jenna McMullin. “The satellite health is nominal.”
NOAA operates two GOES satellites: one for East Coast monitoring (in this case GOES-13 at 105-deg. West longitude) and another, GOES-15, at 135 deg. West longitude for West Coast monitoring. An in-orbit spare, GOES-14, was turned on after GOES-13 failed. Though not optimally positioned as far east as the primary satellite, GOES-14 will be a temporary gap filler while engineers work to repair GOES-13.
“As we’ve already seen this year, severe weather is a constant, potentially deadly threat in the United States, which means NOAA’s satellites — including the backups — must be ready for action, so the flow of data and imagery can continue without interruption,” said Mary Kicza, assistant administrator for NOAA’s Satellite and Information Service, in a May 29 news release.
Engineers are reactivating GOES-13, bringing it out of storage mode and using star trackers to get it pointed toward Earth, Mahmot says. They will then monitor the spacecraft to ensure it is able to maintain a precise attitude for at least 24 hr.
If all goes to plan, operators will begin activating the instruments at 2 p.m. EDT on May 30; this sequence usually takes about 28 hr. to execute.
Because GOES-14 was activated to handle East Coast monitoring, Mahmot says senior NOAA officials have approved a plan to allow heating of the GOES-13 satellite and performing an outgassing process on the sounder in an effort to reduce noise on the short-wave channel that was noticed before the attitude problem last week. By heating the satellite up, operators hope to “bake off” any contaminants that may interfere with data transfer.
The outgassing will require about four days, followed by a one-day cool-off period.
Mahmot says GOES-13 could be ready for a return to full operational status as soon as June 5.