ESA Hubble Status Report – February 2004

Mission Status

The HST observatory is operating nominally with all instruments functioning.
The Phase I deadline for the 13th Cycle of HST observations is on the 23
January 2004 with the peer review taking place in Baltimore at the end of
March. Notification to the PIs of successful proposals is on 4 April.

On Friday 16 January, NASA announced that there would be no further Hubble
servicing missions, with future Shuttle missions going exclusively to ISS
(International Space Station). The decision was taken by Sean O’Keefe, the
NASA administrator, and was principally for reasons of crew safety rather
than budget. The next servicing mission, SM4. originally scheduled for 2004, was expected to occur in 2006 when Shuttle flights had resumed after the
Colombia accident. In addition to installing two new scientific instruments
(WFC3 and COS), the mission would have addressed issues concerned with gyros
and battery lifetime. Without this attention to spacecraft health, Hubble
capabilities are expected to degrade over the next 3-4 years with the loss
of a full gyro complement forcing special operational strategies.

The fate of the two new instruments scheduled for installation during SM4 is
currently uncertain. There is some discussion about the possibility of
launching them as part of Explorer-class missions but it is too early to
comment in detail.

Science Highlights

HST observing in 2003 has included many very large survey programmes that
build on the earlier successes of the Hubble Deep Fields (HDF). In addition
to the GOODS Treasury programme carried out with the Advanced Camera for
Surveys (ACS), the ACS is currently being used for an Ultra Deep Field (UDF)
exposure within the GOODS area of the Chandra Deep Field – South. This is a
direct successor to the HDF and the STScI director is devoting a large
allocation of discretionary time (412 orbits) to a single pointing in order
to go as deep as possible – up to 1.5 magnitudes fainter than the original
WFPC2 HDF in some bands. As a supplement to the primary imaging observations
being taken with the Wide Field mode of the ACS, several other HST
instruments will be used in parallel to produce both additional images and
slitless spectroscopic data. The UDF observations will be completed in
January 2004 and a full public data release is expected in mid-February or
soon thereafter.

An interesting aspect of the UDF parallels is a deep observation with the
grism mode of the ACS high-resolution camera. This will be by far the
deepest observation using this particular setup. All the data processing for
this slitless spectroscopy will be carried out at the ST-ECF who are
responsible for the HST grism software developments.