SIRAL-2 tests in progress

SIRAL-2 is a radar altimeter carried by CryoSat-2 that will be used to measure the height between spacecraft and ice sheets on Earth.
By superposing data after several passes over the same place, it can be deducted how this height changes. After complex processing of data and use of different modes of the SIRAL-2, it can be established if over a defined area, and a defined period of time, there is accumulation or melting of ice.

The performance verification of this instrument is essential to assure the success of the CS-2 mission. A last SIRAL-2 series of tests is foreseen during the CS-2 launch campaign.

These tests require the Radar altimeter to be activated as in space conditions. After radar pulses are emitted by SIRAL-2, the antenna (s) will receive artificial echoes generated by the Electrical Ground Segment Equipment (EGSE).
An anechoic wall (in blue) placed opposite to the radar antennas will absorb the radiated emissions from the instrument. This wall also carries horns (not visible here) to send echoes artifically generated by the EGSE.

Cryosat-2 configured for SIRAL-2 tests:


Philippe from Alcatel Alenia space* on the SIRAL-2 EGSE console. This Ground Equipment processes radar pulses and simulates radar echoes responses via horns placed on the wall.


Rob, from ESA is positioning the "wall" with the best accuracy. This distance is very important for a good "understanding"' and processing of these echoes responses by the SIRAL-2 instrument.


Now, as you can see, test is in progress: the red lamp warns staff that the radar altimeter is in function.


Good news: DORIS flight-like tests have been successfully completed the last days. DORIS is a GPS-like instrument developed by CNES that provided the exact location of the spacecraft at a certain time. DORIS is always coupled with SIRAL-2 because the position of the spacecraft during the SIRAL-2 measurements is required to process the radar altimeter data any further.

*Main developer of the SIRAL-2 instrument