Status Report

HESSI Spacecraft Safely Reaches Orbit

By SpaceRef Editor
February 5, 2002
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NASA’S High Energy Solar Spectroscopic Imager, or HESSI, lifted off this afternoon from Cape Canaveral Air Force Station, Fla. at 2:29 p.m. EST. During its planned two-year mission HESSI will study the secrets of how solar flares are produced in the Sun’s atmosphere.

Tucked inside a Pegasus XL rocket, attached to the under belly of the Orbital Stargazer
L-1011 aircraft, the spacecraft was carried approximately 113 nautical miles east-southeast of the Cape to an altitude of about 39,000 feet. The Pegasus drop occurred at 3:56 p.m. EST, and after a short powered sequence, delivered the 645-pound HESSI spacecraft into a circular orbit 373 miles above the Earth, inclined at 38 degrees to the equator.

“We’re extremely thrilled to report the Pegasus drop went without a hitch,” said Frank Snow, HESSI Project Manager at NASA’s Goddard Space Flight Center, Greenbelt, Md.

Controllers at the University of California, Berkeley, made initial contact with the spacecraft at
5:33 p.m. EST.

HESSI will help unlock some of the secrets of these gigantic explosions in the Sun’s atmosphere, providing scientists with the first high-fidelity color movies of solar flares in X-rays and gamma rays, which is their highest energy emissions. Scientists hope to capture hundreds of X-ray and gamma ray flares during the spacecraft’s planned two-year mission.

Science operations should begin in about three weeks, after germanium detectors inside the
X-ray/gamma-ray imaging spectrometer are cooled to their operating temperature of minus 320 degrees Fahrenheit, turned on and checked out.

HESSI is the first NASA Small Explorer mission being managed in the ‘principal investigator’ mode. Professor Robert Lin of the University of California, Berkeley, is responsible for many aspects of the mission, including the science instrument, spacecraft integration and environmental testing, and spacecraft operations and data analysis.

The HESSI scientific payload is a collaborative effort between the University of California, Berkeley, NASA’s Goddard Space Flight Center, the Paul Scherrer Institut in Switzerland, and the Lawrence Berkeley National Laboratory in Berkeley. The mission also involves scientific participation from France, Japan, The Netherlands, Scotland, and Switzerland.

The Explorers Program Office at Goddard manages the HESSI mission for NASA’s Office of Space Science in Washington, D.C. Spectrum Astro, Inc. of Gilbert, Ariz., constructed the HESSI spacecraft and provided integration support.

The HESSI mission cost, including the spacecraft, science instrument, launch vehicle, and mission operations and data analysis, is approximately $85 million.

For additional details about the mission, go to:

SpaceRef staff editor.