Friday, July 14, 2006

Update on Hubble's main camera

Sorry for the blog silence. Family trips, the Fourth, and now a research trip. Which brings me to the topic. I've got the news from several friends here at the Institute (Space Telescope Science Institute, which operates the Hubble) that the main camera, ACS (Advanced Camera for Surveys), is back up and running. Actually, it has been for a few days. They made the switch to the so-called "side 2" electronics, the back-up systems, without much trouble. They're taking science data already, although there's still more calibration to be done. Some improvements are already showing. They've lowered the temperature 3-4 degrees C, which has improved things like lowering the "dark current," which is the false signal that comes through even when there's no light. And I think the number of "hot pixels," bright specks that deface the images, have been reduced.

With things going well on the current shuttle flight, there's optimism that Hubble Servicing Mission 4 will indeed go through. Among the tasks on that mission will be installing two new instruments (COS-Cosmic Origins Spectrograph, and WFC3-Wide Field Camera 3), replacing some gyroscopes and batteries(?), and fixing the STIS (Space Telescope Imaging Spectrograph). Intriguingly, there's an idea to use a robot--which I believe has already been created--to do some of the trickier manual tasks needed for opening it STIS or ACS? for repairs. From what a friend described to me, this robot would be perched on top of the camera housing and would unscrew the needed screws. Easier than trying to do this kind of thing with big, bulky, pressure-suit gloves. Very clever idea, and I'll be interested to see if it's approved. Maybe this is supposed to be for STIS. But there is also an idea for fixing the side 1 electronics in ACS, so that there'd still be a backup in case the side 2 system failed.