On-Orbit Testing of SDO, March 28–April 25, 2018

SDO uses two high-gain antennas (HGAs) on the spacecraft to maintain continuous contact with the SDO ground station in New Mexico. Should one of those antennas fail we would have to roll the spacecraft to a variety of position angles during the year to keep the remaining HGA in contact with the ground station. The SDO Team will be testing the procedures needed to run SDO on a single HGA from March 28, 2018, to April 25, 2018.

During the test the roll angle of SDO will vary from 0 to 180 degrees. Near-realtime images from SDO may appear with the incorrect position angle, similar to what happens during an instrument calibration. To ensure you have correctly aligned science data, please use the exported images from the JSOC or the SSW IDL routines aia_prep.pro and hmi_prep.pro. If you use other software for data analysis, make sure you properly account for the value of the CROT2 when preparing the data.

Remember: This is only a Test!"