Saturday, February 3, 2007

Hubble's Broken Camera

There's some confusion this week since Hubble's Advanced Camera for Surveys (ACS) stopped functioning. Maybe this blog will give me a platform for explaining it and tying it back to what it means to upgrade Hubble.

The ACS has had problems for the past year now and it looks like it's pretty much toast, but that does not mean that Hubble is toast and it's important to emphasize this. Science operations continue on Hubble using the other instruments on board. Hubble is an observatory, a veritable swiss-army-knife in space. The good people at STSCI (the group that governs the scientific use of Hubble) have switched their slate of scientific missions to a contingency plan that utilized the other, still-functioning instruments on Hubble.

What this means for servicing is still TBD. But it's clear the astronauts will have a pretty long checklist when they visit Hubble on SM4 (projected to launch September 2008). In addition to replacing batteries and gyros, installing 2 new instruments (widefield planetary camera 3 and cosmic origins spectrograph), I was under the impression they were going to try to fix STIS (currently dead weight on hubble) in orbit; could they fix ACS too? Is there room for all this equipment? Enough time?

I'm asking you-- you're the engineer, I'm just a man with a movie camera. Wait, you're not an engineer? I guess technically, I'm not even a man with a movie camera... just a bozo with a blog talking about stuff. Perhaps the original press release about the ACS malfunction can shed some light on this:


GREENBELT, Md. - NASA engineers are examining a problem related to the
Advanced Camera for Surveys (ACS) aboard the agency's Hubble Space

On Jan. 27, the observatory entered a protective "safemode" condition
at 7:34 a.m. EST. An initial investigation indicates the camera has
stopped functioning, and the input power feed to its Side B
electronics package has failed.

The instrument had been operating on its redundant electronics since
June 30, 2006, when NASA engineers transitioned from the primary,
Side A, electronics package due to a malfunction. Engineers currently
are assessing the option to return ACS science operations to the
primary electronics so that observations could resume in a reduced

Hubble was recovered from safemode around 2 a.m. EST on Jan. 28, and
science observations will resume this week using the remaining Hubble
instruments: Wide Field Planetary Camera 2, Near Infrared Camera
Multi-Object Spectrograph, and the Fine Guidance Sensors.

In November 2006, the Space Telescope Science Institute in Baltimore
selected a set of backup non-ACS science programs for use in case of
a future ACS anomaly. These programs now will be inserted into the
science schedule to maintain a highly productive observing program.

An Anomaly Review Board was appointed on Jan. 29, to investigate the
ACS anomaly. The board will perform a thorough investigation and
assessment to decide the best course of action. The board is
scheduled to present their findings and recommendations by March 2.

"It is too early to know what influences the ACS anomaly may have on
Hubble Space Telescope Servicing Mission-4 planning" said Preston
Burch, associate director/program manager for the Hubble Space
Telescope. "It is important that the review board conduct a thorough
investigation that will allow us to determine if there are any
changes needed in the new instruments that will be installed on the
upcoming servicing mission so that we can be sure of maximizing the
telescope's scientific output. We are continuing to make excellent
progress in our preparations for the servicing mission, which is
presently targeted to fly in September 2008."

The Advanced Camera for Surveys is a third-generation instrument
consisting of three electronic cameras, filters and dispersers that
detect light from the ultraviolet to the near infrared. The
instrument was installed during a March 2002, servicing mission. It
was developed jointly by NASA's Goddard Space Flight Center,
Greenbelt, Md., Johns Hopkins University, Baltimore; Ball Aerospace,
Boulder, Colo.; and the Space Telescope Science Institute.

The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency. The Space Telescope
Science Institute conducts Hubble science operations. The Institute
is operated for NASA by the Association of Universities for Research
in Astronomy, Inc., Washington.

For information about the Hubble Space Telescope, visit:

1 comment:

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