your Congressperson
http://www.house.gov/house/MemberWWW.html
or http://www.house.gov/writerep/

The Honorable Representative F. James Sensenbrenner, Jr
Chairman of the House Science Committee
2332 Rayburn House Office Building
Washington, D.C. 20515-4909

The Honorable Representative James T. Walsh
Chair, Subcommittee on VA, HUD and Independent Agencies
2351 Rayburn House Office Building 
Washington, DC 20515

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Dear Representative 

I am disturbed by the recent NASA decision to de-orbit the Compton Gamma
Ray Observatory (CGRO) beginning May 28 for safety reasons. 

Safety is clearly and correctly a very high priority in everything that
NASA does.  However, it is important to have a realistic safety policy
that is applied uniformly to all missions.  The question is: Does
continuing operation of CGRO present unacceptable risk?  The risk of
continuing to fly CGRO was inconsistently described at the press
conference on March 24, 2000.   According to the NASA officials at the
press conference the decision was based upon a casualty risk of 1/1000
if another gyroscope failed, yet in response to a reporter's question
those same officials confirmed a risk estimate of 1 in 4 million for a
controlled reentry using zero gyroscopes. 

The scientific case for continuation of the mission is beyond question.
The NASA Senior Review made a strong case for continuing the CGRO
Mission.  The end of CGRO operations would affect virtually every
sub-discipline of astrophysics. The study of gamma-ray bursts and
high-energy emission from solar flares during the solar maximum period
will be particularly hard-hit.  With the damage suffered by the HESSI
satellite during tests, loss of CGRO leaves the US with no capability
for observing high-energy radiation from solar flares during the maximum
of solar activity.   The loss of CGRO will also be detrimental for many
of the scientific objectives of presently operating and upcoming
high-energy astrophysics missions, because it provides
targets-of-opportunity, all-sky monitoring and coordinated observations
over a very broad high-energy range.  These missions include: ACSA,
BeppoSAX, CHANDRA, INTEGRAL, HETE, RXTE, SWIFT, and XMM.  There is no
spacecraft planned for the next several years that can accomplish these
objectives. 

I strongly urge you to request that an independent review committee be
convened to determine the true risks of continuing the CGRO mission and
to balance these with the continuing scientific return.  The committee
should review the options for continuing the CGRO mission and compare
the risks of CGRO to the risks of other NASA science activities.  The
reentry should be delayed for the time necessary for the committee to
make its report.  Since CGRO is currently operating in a safe,
long-lived orbit with a lifetime of greater than four years, the
possibility of human harm during the time of such a study is minimal.
It would be a national tragedy to unnecessarily destroy one of America's
Great Observatories. 

I thank you for your past support and for your immediate attention to
this issue. 

Sincerely yours,