SWAP and LYRA Calibration Campaigns from September 5 to 8, 2022

We would like to point out to all PROBA2 data users that there were gaps in the regular science data streams from SWAP and LYRA from 2022-09-05 to 2022-09-08 due to special calibration campaigns. 

 

LYRA performed a long calibration campaign starting at 2022-09-06 at 14:30 UT using units 2 and 3.

 

The SWAP campaign started on 2022-09-05 at 07:30 UT already, with a regular SWAP calibration at normal detector temperatures, during which the satellite was off-pointed by 5 degrees to obtain dark current images (thus without the Sun in the frame). After this first part of the campaign, SWAP was put in IDLE mode to clear its memory buffer. We then also started a so-called "bake-out" of SWAP, where the temperature of the SWAP detector was raised to about 50 degrees (as opposed to the temperatures around -0.5 degrees that we normally get at this time of year). Once the heating was stopped (after ~24h), the spacecraft was again off-pointed by five degrees and while the detector was cooling down, both SWAP and LYRA measured temperature-sensitive dark current, the main source of instrumental noise. These measurements will allow us to improve the calibration of our observations.

 

Once normal SWAP detector temperatures were again reached, the satellite was returned to its nominal sun-centered pointing and regular SWAP imaging and LYRA measurements recommenced around 11:15 UT on 2022-09-07. A second SWAP calibration at normal detector temperatures, during which the satellite will be off-pointed by 5 degrees again, took place on 2022-09-08 in the morning.