On February 5th. 2002. NASA's High Energy Solar Spectroscopic Imager.
or HESSI spacecraft. was launched aboard a Pegasus XL rocket.
It was dropped at 3:58 pm Eastern from the belly of an L1011 aircraft that took off from NASA's Kennedy Space Center in Florida.
HESSI was designed to obtain pictures of solar flares using X-rays and gamma rays.
and explore the basic physics of particle acceleration and energy release in those solar flares.
Nearly two months after the successful launch. the satellite was rechristened
RHESSI - the Reuven Ramaty High-Energy Solar Spectroscopic Imager.
The new name was to honor the late NASA scientist who pioneered the fields of solar-flare physics. gamma-ray astronomy and cosmic ray research.
Among the many discoveries by RHESSI - scientists using the spacecraft measured the roundness of the sun and found it is not a perfect sphere.
Originally planned as just a two-year mission. the RHESSI spacecraft continues to document countless solar flares.