Trent J. Perrotto
Headquarters, Washington
202-358-0321
ltrent.j.perrotto@nasa.gov
Lynn Chandler
Goddard Space Flight Center, Greenbelt, Md.
301-286-2806
lynn.chandler-1@nasa.gov
RELEASE: 12-005
NASA'S ROSSI X-RAY TIMING EXPLORER COMPLETES MISSION OPERATIONS
WASHINGTON -- After 16 years in space, NASA's Rossi X-ray Timing
Explorer (RXTE) has made its last observation. The satellite provided
unprecedented views into the extreme environments around white
dwarfs, neutron stars and black holes.
RXTE sent data from its last science observation to the ground early
on Jan. 4. After performing engineering tests, controllers at NASA's
Goddard Space Flight Center in Greenbelt, Md., successfully
decommissioned the satellite on Jan. 5.
RXTE far exceeded its original science goals and leaves astronomers
with a scientific bounty for years to come. Data from the mission
have resulted in more than 2,200 papers in refereed journals, 92
doctoral theses, and more than 1,000 rapid notifications alerting
astronomers around the globe to new astronomical activity.
"The spacecraft and its instruments had been showing their age, and in
the end RXTE had accomplished everything we put it up there to do,
and much more," said Tod Strohmayer, RXTE project scientist at
Goddard.
The decision to decommission RXTE followed the recommendations of a
2010 review board tasked to evaluate and rank each of NASA's
operating astrophysics missions.
"After two days we listened to verify that none of the systems we
turned off had autonomously re-activated, and we've heard nothing,"
said Deborah Knapp, RXTE mission director at Goddard.
The 7,000-pound satellite is expected to re-enter the atmosphere
between 2014 and 2023, depending in large part on solar activity. To
celebrate the spacecraft's long and productive career, astronomers
will hold a special session on RXTE during the 219th meeting of the
American Astronomical Society (AAS) in Austin, Texas. The session is
scheduled for Tuesday, Jan. 10, at 3 p.m. CST. A press conference on
new RXTE results will also be held at the meeting on Jan. 10 at 1:45
p.m. EST.
RXTE opened a new window into the workings of neutron stars and black
holes. Using its data, astronomers established the existence of
highly magnetized neutron stars (known as magnetars) and discovered
the first accreting millisecond pulsars, a previously unseen stage in
the formation of "recycled" millisecond radio pulsars that were first
glimpsed in the early 1980s. The observatory also provided the first
observational evidence of "frame-dragging" in the vicinity of a black
hole, an effect predicted by Einstein's general theory of relativity.
RXTE carried three instruments, the Proportional Counter Array (PCA)
and the High Energy X-ray Timing Experiment (HEXTE), which could be
directed to specific targets. The PCA was developed by Goddard to
cover the lower part of the energy range. HEXTE was built by the
University of California at San Diego for exploring the upper energy
range.
The observatory's instruments measured variations in X-ray emission on
timescales as short as microseconds and as long as months across a
wide energy span, from 2,000 to 250,000 electron volts. For
comparison, the energy of a typical dental X-ray is around 60,000
electron volts.
A third instrument, called the All-Sky Monitor, was developed by the
Massachusetts Institute of Technology (MIT) in Cambridge. It scanned
about 80 percent of the sky every orbit, giving astronomers the
ability to monitor the variable and often unpredictable X-ray sky and
to record long-term histories of bright sources.
The astronomical community has recognized the importance of RXTE
research with five major awards. These include four Rossi Prizes
(1999, 2003, 2006 and 2009) from the High Energy Astrophysics
Division of the AAS and the 2004 NWO Spinoza prize, the highest Dutch
science award, from the Netherlands Organization for Scientific
Research.
The mission was launched as XTE aboard a Delta II 7920 rocket on Dec.
30, 1995, from Cape Canaveral Air Force Station in Florida. It was
renamed RXTE in early 1996 in honor of Bruno Rossi, an MIT astronomer
and a pioneer of X-ray astronomy and space plasma physics who died in
1993. RXTE was managed by Goddard.
For more information on RXTE, visit:
http://www.nasa.gov/centers/goddard/missions/rxte.html
-end-
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