re hst servicing mission scheduled for days prb access digex net pat writes in article c a at e z zoo toronto edu henry zoo toronto edu henry spencer writes no the thing is designed to be retrievable in a pinch indeed this dictated a rather odd design for the solar arrays since they had to be retractable as well as extendable and may thus have indirectly contributed to the array flapping problems why not design the solar arrays to be detachable if the shuttle is going to retunr the hst what bother are some arrays just fit them with a quick release one space walk or use the second canadarm to remove the arrays you may want to put hubble back in the payload bay for a reboost and you don t want to clip off the panels each time for the gamma ray observatory one of the design requirements was that there be no stored energy mecahnisms springs explosive squibs gas shocks etc used for deployment this was partially so that everything could be reeled back in to put it back in the payload bay and partially for safety considerations i ve heard that the wings on a cruise missile would cut you in half if you were standing in their swath when they opened back when the shuttle would be going up every other day with a cost to orbit of per pound everybody designed things for easy servicing david m palmer palmer alumni caltech edu palmer tgrs gsfc nasa gov
