[meteorite-list] Green Light for the Deployment of the Second MARSIS Boom (Mars Express)

[Ron Baalke]

http://www.esa.int/SPECIALS/Mars_Express/SEMSL01DU8E_0.html

Green light for the deployment of the second MARSIS boom
European Space Agency
Mars Express 
7 June 2005

Following in-depth analyses performed after the deployment of the first
MARSIS antenna boom on board Mars Express, ESA has decided to proceed
with the deployment of the second 20-metre antenna boom.
 
The full operation will be performed during a time frame starting 13
June and nominally ending on 21 June.

A delay in the execution of the second boom deployment was necessary,
due to problems encountered with the first deployment in early May this
year. During the deployment, one of the antenna hinges (the tenth) got
stuck in an unlocked position. Analysis of data obtained from earlier
ground testing suggested a potential solution.

The Mars Express spacecraft control team at ESA's Spacecraft Operations
Centre (ESOC) succeeded in unblocking the hinge by exposing the cold
side of the boom to the Sun. This warmed the hinges and the boom quickly
became unstuck. In the end, the first boom deployment was completed on
10 May.

The lessons learnt during the first boom deployment were used to run new
simulations and determine a new deployment scenario for the second boom.
This scenario contains an additional sun-heating phase, to get the best
possible thermal conditions for all hinges.

The deployment of the third (7-metre) third MARSIS boom is not
considered critical. It will be commanded only once the ESA ground
control team have re-acquired signal from the spacecraft, and made sure
with a sequence of tests that the second boom is correctly locked into
position and the spacecraft is well under control.

After this event MARSIS, the Mars Express Sub-Surface Radar Altimeter,
will enter into a commissioning phase for the next few weeks, before
starting to look at Mars' ionosphere during martian daylight, and to
probe down below the Martian surface during the martian night.

For more information please contact:

Fred Jansen
Mars Express mission manager
fjansen @ rssd.esa.int