🚀 go-pugleaf

BrianT@cup.portal.com (Brian Stuart Thorn) writes:

>The folding, umbrella-type antennae have been used at least ten times
>in space (that is, two each on TDRS-A, TDRS-C, TDRS-D, and TDRS-E, one
>on ATS-6 (late-70s pathfinder comsat) and one on Galileo.
> 
>Only the one on Galileo failed to open on command, and there is still
>hope it will be coaxed open. (They haven't tried brute force yet.)

>Lesson:  OPEN THE DAMNED ANTENNA IMMEDIATELY AFTER LAUNCH!!!

And again writes,

>  Ryan...
>   
>  Galileo's umbrella-type High Gain Antenna was left in the folded
>  position because it was thought that the high temperatures it would
>  encounter during the Venus flyby portion of the mission could warp
>  the antenna. They attempted to open the antenna only after the Venus
>  flyby, when Galileo flew farther from the Sun. It was jammed.
   
>  Cassini, I think, will have a standard hard HGA, similar to the
>  Voyager and Magellan antennae. I hope the Galileo problem does not
>  prevent future spacecraft from using the folding antenna design. It
>  worked quite well on the TDRS satellites.
>  
>  -Brian

Is there a possiblity that, despite Galileo's HGA parasol, solar heat
could have still been a factor in its failure to deploy?  Especially
when one considers that for the nine successful deployments out of
ten, cited above, every corresponding spacecraft never left earth
orbit, while Galileo got as close to the sun as the planet Venus.

Curt