The Latest Hubble Malfunction
Published on Jan 31, 2007 at 1:37 pm.
3 Comments.
Filed under space telescopes.
I had heard about this a couple days ago, but I held off posting until I was more sure of the issue. It appears that the Hubble Space Telescope has had another instrument failure. The malfunctioning instrument is the Advanced Camera for Surveys (ACS), which is one of the main cameras.
It is not clear whether or not the camera can be made to operate from the ground. It was already operating on its backup electronics package after a fault in its primary electronics a few months ago. But, even if the camera were to never become operational again, the Hubble telescope is still usable. There isn’t just one instrument, or even camera, on board. However, the ACS was a very heavily used instrument of late. Still working is the Wide Field and Planetary Camera 2 (WFPC2). While some targets originally to be studied using ACS may be studied with WFPC2, the two instruments are not redundant, and they have different capabilities, so the exact same science is not possible by changing instruments. Also operational is the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). NIMCOS does not duplicate the other instruments because it is an infrared camera. It should be noted, that it, too, is not operating at peak efficiency due to a cooling problem that developed soon after it was installed during the second servicing mission in 1997.
ACS was the most sophisticated camera on board, so it is no surprise that it has been a prime choice for many observations. But, now, it looks like WFPC2 will be carrying the lions share of observations. But, as I said, the loss of ACS does not render HST dead, as so many news reports make it sound. It simply reduces the types of observations that it can be used for. If anything, this is almost good news to those researchers who really need the WFPC2, because it cuts out some of the competing observing proposals that could only use ACS. And, they have not given up hope on the ACS. They are considering returning to the primary electronics package and operating the camera with reduced capabilities.
Now, none of this should really be so surprising. The Hubble Space Telescope is a very complicated piece of equipment. It is an orbiting observatory. It is a satellite as well as a telescope. And, it was designed for routine servicing missions. The plan was for a servicing mission every 3 years. The last servicing mission was in March of 2002. That is four years ago. It is already past due for a servicing mission. Anyone who drives a car should be aware that if you keep driving without doing any routine service, like oil changes, new tires,new battery, etc., then eventually you’ll have problems. The car won’t run. But, as happens with many older pieces of equipment, as they get older, they need more often. The same is true with HST. It needs new batteries, new computer, new instruments, new gyroscopes, etc. All these things are meant to be checked and replaced every few years. And, the next servicing mission is still two years into the future. That will then be three years past due for service, and six years after the last service. It isn’t really clear if HST will continue to be able to provide science data that long. They are nursing it along, but things do break. One of the most worrisome problems may be the gyroscopes. They are the most susceptible to wearing out. And, they need to be replaced now and then. Already some have worn out. HST has six of them. It needs three to stabilize it for observations. A procedure has been worked out to use two gyroscopes in an emergency if all but two die. The next servicing mission will replace all gyroscopes and install new batteries. WFPC2 will be traded out for the Wide Field and Planetary Camera 3 (WFPC3), and the failed optical spectrometer will be traded for a new spectrograph, the Cosmic Origin Spectrograph. Now, they will need to think about what to do with ACS. That is a lot to do on one mission, and I wonder if they’ll be able to do it all.
But, for now, the rumors of the Hubble Space Telescope’s death have been greatly exagerated.
-Astroprof
(Images courtesy of NASA)
Louise on January 31, 2007 at 5:50 pm: 1
Shuttle Atlantis’ last flight, to repair Hubble, is currently scheduled for September 11, 2008.
Astronomy Buff - Astronomer Depression Skyrocketing Over Loss of Hubble Camera. Are Mass Suicides Inevitable? on January 31, 2007 at 6:31 pm: 2
[…] Of all the things I read so far from bloggers, I like AstroProf’s balanced view the best. The Bad Astronomer did a great job too. You’re not going to get balanced from me today. The Advanced Camera for Surveys on board the HST has a glorious number of achievements under its belt. I have commented and written numerous times that that camera has given us the most important image ever taken: The Hubble Deep Field. That image so inspired me, that I made a video about it. […]
Brian on January 31, 2007 at 9:51 pm: 3
A good argument - I think - for having a robust and diverse environment for launch systems. Right now .. Shuttle is it. If Shuttle ain’t flying then service missions are off. If you have a reduced fleet - and we’re not making any more Shuttles, ever - then you have pick and choose.
There aren’t any good calls to be made here - except to go back twenty years and promote commercial space flight.