SOHO Recovery Updates

The SAS data received on 11 August have been analyzed. It was confirmed that SOHO is spinning around an axis close to the Z axis at a rate of -6.9 deg/sec (rotation period 52.6 sec). The rotation vector is 1.8 deg from the Z axis towards the X axis and 7.6 deg from the Z axis towards the -Y axis. The angle between the rotation axis and the Sun is 36.7 deg.

The X-band ranging on 11 August was not successful. The cause for the failure is still under investigation.

Today we started ranging with SOHO. We had a total of four session where we acquired ranging data, each lasting a couple of minutes.

Thawing of the tank has started yesterday evening at 22:39 UT. It was interrupted today at 20:03 UT in order to recharge the batteries. Analysis of the power data revealed a slightly negative power balance, i.e. we draw power from the batteries when the heaters are on. We therefore have to recharge the batteries from time to time. Batteries charged for 20 hours should have enough capacity to allow us to turn the heaters on for about 3 days. Presently we estimate that about two cycles of charging/heating will be necessary to thaw the hydrazine in the tank.