PFS issue on Venus Express, PFS scanner stuck in its closed position Options

[Rakhir]

Bad news for PFS. I hope they will be able to solve this issue.

The PFS scanner is stuck in its closed position.
Several attempts to move it were made at the time, but the instrument did not respond. Experts suspected a thermal problem by which low temperatures were blocking the rotation of the mechanism.
Another attempt to move the scanner was made on 16 March 2006, in warmer flight conditions. Unfortunately, the scanner remains stuck.

The next opportunity to perform another test on the spacecraft will be end of April, after the Venus Orbit Insertion.

From http://sci.esa.int/science-e/www/object/in...fobjectid=38964

[deglr6328]

I am only able to remember one instance where a stuck instrument cover was removed DURING the mission. The Viking Mars scoop cover that was shaken out over several days of back and forth motions of the motor controlling it. Are there more examples? All the others I can think of, Galileo HGA, Pioneer camera cover not popping off, Venera camera cover not popping off and some missions where solar panels fail to open, were never fixed....

[tasp]

I am only able to remember one instance where a stuck instrument cover was removed DURING the mission. The Viking Mars scoop cover that was shaken out over several days of back and forth motions of the motor controlling it. Are there more examples? All the others I can think of, Galileo HGA, Pioneer camera cover not popping off, Venera camera cover not popping off and some missions where solar panels fail to open, were never fixed....

Voyager II had an apparent indication of the science boom failing to lock in place when it actually had. (kind of the reverse of the problem in this case)

One of the US lunar Surveyor crafts had a surface sensor (gamma ray surface composition device?) fail to deploy completely and the sampling scoop was used to position it correctly.

The Explorer craft (39?) orbiting the moon had incomplete extensions of the antennas, but the problem did not substantially effect the science return. Booms only extended (IIRC) 700+ feet instread of 1000+ ft.

Space shuttles have had payload door alignment problems during opening and closing (or failing to do so), but usually it is the thermal expansion of the vehicle that causes the problem and they know how to alleviate the problem.