An independent panel of astronomers identified three
options for NASA to consider for planning the transition from
the Hubble Space Telescope (HST) to the James Webb Space
Telescope (JWST) at the start of the next decade.

The panel, chaired by Prof. John Bahcall, Institute for
Advanced Study, Princeton, N.J. chartered by NASA earlier
this year, submitted their report to the agency this week.

NASA’s current plans are to extend the life of the HST to
2010 with one Space Shuttle servicing mission (SM 4) in 2005
or 2006. The plan is tentative pending the agency’s return to
flight process and the availability of Shuttle missions. NASA
plans to eventually remove the HST from orbit and safely
bring it down into the Pacific Ocean.

“NASA is deeply appreciative to Prof. Bahcall and the panel
for getting this thoughtful report to us ahead of schedule,”
said Dr. Ed Weiler, NASA’s Associate Administrator for Space
Science. “We have a big job to do to study the panel’s
findings and consider our options, and we will respond as
soon as we have time to evaluate their report,” Weiler said.

The three options presented by the HST-JWST Transition Plan
Review Panel, listed in order of priority, are:

“1. Two additional Shuttle servicing missions, SM4 in about
2005 and SM5 in about 2010, in order to maximize the
scientific productivity of the Hubble Space Telescope. The
extended HST science program resulting from SM5 would only
occur if the HST science was successful in a peer-reviewed
competition with other new space astrophysics proposals.”

“2. One Shuttle servicing mission, SM4, before the end of
2006, which would include replacement of HST gyros and
installing improved instruments. In this scenario, the HST
could be de-orbited, after science operations are no longer
possible, by a propulsion device installed on the HST during
SM4 or by an autonomous robotic system.”

“3. If no Shuttle servicing missions are available, a robotic
mission to install a propulsion module to bring the HST down
in a controlled descent when science is no longer possible.”

In addition, the panel described various ways to ensure
maximum science return from the HST if none, one or two
Shuttle servicing missions are available.

“A lot of astronomers and NASA officials were astonished,
when we said our report was ready just one week after our
public meeting. This was possible because we reached
unanimous agreement on our conclusions very quickly;
remarkable when you consider there were six independent-
minded scientists on the panel. Our secret is we did our
homework very thoroughly. Many people helped to educate us,”
Bahcall said.

For information about NASA and space science on the Internet,
visit:

http://www.nasa.gov

The HST-JWST Transition Panel report is available on the
Internet at:

http://www.nasa.gov/audience/formedia/features/MP_Public_Reports.html

Information about the panel, including membership and
charter, is available at:

http://hst-jwst-transition.hq.nasa.gov/hst-jwst/

For information about the Hubble Space Telescope on the
Internet, visit:

http://oposite.stsci.edu/

For information about the James Webb Space Telescope on the
Internet, visit:

http://ngst.gsfc.nasa.gov/