RHESSI

USA

International Sat. n°:

USA satellite n°:

High Energy Solar Spectroscopic Imager, later renamed RHESSI (Reuven Ramaty High-Energy Solar Spectroscopic Imager)
Also called Explorer 81 or SMEX 6

Launch data:

Designation:27370 / 02004A
Launch date05 Feb 2002 - 20:58:12 UT
Launch site CC, L-1011 RW3
Launch vehicle:Pegasus-XL (S/N F31 / #32)
Mission:Government/Civil: Astrophysics, Sun study
Intermediate LEO Earth orbit:
Perigee / Apogee 588 x 609 km
Eccentricity 1,51E-03
Inclination 38 deg
Period 96.65 min

HESSI will investigate the physics of particle acceleration and energy release in solar flares through an unprecedented combination of high resolution imaging and spectroscopy of X-rays and gamma rays from 2 keV to 20 MeV during the next solar maximum.

In Mar 2000, the satellite was damaged when during a test it was shaken 10 times harder than intended. Once on orbit, the satellite proved to work properly.

Specifications:

Prime contractorSpectrum Astro, Inc
Platformderived from SA-200S
OperatorSpace Sciences Laboratory, UC Berkeley/NASA
Mass at launch293 kg
Mass in orbit  
Dimension  
Solar array 4 panels
Stabilization spin stabilized (15 rpm)
DC power414 W
Design lifetime3 yrs - still active

It uses Fourier-transform imaging with 12 bi-grid modulation collimators and cooled germanium and silicon detectors mounted on a Sun-pointed spin-stabilized spacecraft in a low-altitude equatorial orbit. HESSI will carry out the first imaging spectroscopy in hard X-rays with 2 arcseconds angular resolution, time resolution to tens of ms, and \sim1 keV energy resolution; the first gamma-ray line spectroscopy from a spacecraft with \sim1 keV energy resolution; and the first gamma-ray line and continuum imaging with 20 arcseconds angular resolution.

Explore basic physics of particle acceleration and explosive energy release in solar flares.
Ref: #7, #15, #226 - update: 21.10.08