Basically, engineers hit the reset button to clear up the telemetry problem. After going through tests and calibration, the camera completed its first science observations just after noon ET (9 a.m. PT) today, NASA said in a status update.
Hubble’s three other main instruments — the Advanced Camera for Surveys, the Cosmic Origins Spectrograph and the Space Telescope Imaging Spectrograph — were unaffected by WFC3’s glitch.
WFC3 was installed during NASA’s final space shuttle servicing mission in 2009. Because of the shuttle fleet’s retirement in 2011, there’s no longer any way to make house calls to Hubble. Any repairs have to be done by sending commands up to the orbiting telescope. For example, a gyroscope problem was fixed last year by commanding the telescope to jiggle itself and free up what was assumed to be a blockage in the gyro.
Hubble’s main successor, the $9.7 billion James Webb Space Telescope, is currently due for launch in 2021, and astronomers are hoping there’ll be some overlap in operations. Last week, Space News quoted Hubble’s mission managers as saying that the nearly 29-year-old telescope’s instruments and major subsystems have a high probability of remaining operational through 2025.
The recovery operation proceeded over the past week unaffected by the partial government shutdown, even though other NASA activities have been curtailed. That’s in line with the space agency’s mandate to protect life and property regardless of its current funding situation.
Here’s Monday’s initial post-recovery status report from NASA:
“NASA has moved closer to conducting science operations again with the Hubble Space Telescope’s Wide Field Camera 3 instrument, which suspended operations on Tuesday, Jan. 8. Today, Jan. 15, the instrument was brought back to its operations mode.
“Shortly after noon EST on Jan. 8, software installed on the Wide Field Camera 3 detected that some voltage levels within the instrument were out of the predefined range. The instrument autonomously suspended its operations as a safety precaution. Upon further investigation, the voltage levels appeared to be within normal range, yet the engineering data within the telemetry circuits for those voltage levels were not accurate. In addition, all other telemetry within those circuits also contained erroneous values, indicating that this was a telemetry issue and not a power supply issue.
“After resetting the telemetry circuits and associated boards, additional engineering data were collected and the instrument was brought back to operations. All values were normal. Additional calibration and tests will be run over the next 48 to 72 hours to ensure that the instrument is operating properly. Further investigation using both the new and the previously collected engineering data will be conducted to determine why those data values were originally incorrect.
“Assuming that all tests work as planned, it is expected that the Wide Field Camera 3 will start to collect science images again by the end of the week.”
And here’s what NASA said today:
“The Hubble Space Telescope’s Wide Field Camera 3 was brought back to full operational status and completed its first science observations just after noon EST today, Jan. 17. The instrument autonomously shut down on Jan. 8 after internal data erroneously indicated invalid voltage levels.
“The Wide Field Camera 3 was installed on Hubble in May 2009 during the last servicing mission. It has taken over 240,000 observations to date and is the most used instrument of Hubble’s current complement.”
This is an updated version of a report that was first published at 10:17 a.m. Jan. 16.