Reuven Ramaty High Energy Solar Spectroscopic Imager
Illustration of RHESSI
|
|
| Names | Explorer-81, SMEX-6 |
|---|---|
| Mission type | Solar observatory |
| Operator |
NASA / Goddard Space Sciences Laboratory |
| COSPAR ID | 2002-004A |
| SATCAT no. | 27370 |
| Website | http://hesperia.gsfc.nasa.gov/rhessi3/ |
| Mission duration | Planned: 2 years Elapsed: 15 years, 22 days |
| Spacecraft properties | |
| Manufacturer | Spectrum Astro |
| Launch mass | 293 kg (646 lb) |
| Dimensions | 2.16 × 5.76 m (7.1 × 18.9 ft) |
| Power | 414 W |
| Start of mission | |
| Launch date | 5 February 2002, 20:58 UTC |
| Rocket | Pegasus XL |
| Launch site | Stargazer, Cape Canaveral |
| Contractor | Orbital Sciences |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Semi-major axis | 6,875.9 km (4,272.5 mi) |
| Eccentricity | 0.0011 |
| Perigee | 490.3 km (304.7 mi) |
| Apogee | 505.3 km (314.0 mi) |
| Inclination | 38.0367° |
| Period | 94.5667 min |
| RAAN | 59.1113° |
| Argument of perigee | 152.3223° |
| Mean anomaly | 207.8129° |
| Mean motion | 15.2265 rev/day |
| Epoch | 2 September 2015, 12:16:06 UTC |
| Revolution no. | 74636 |
| Main telescope | |
| Type | Coded aperture mask |
| Focal length | 1.55 m (5.1 ft) |
| Collecting area | 150 cm2 (0.16 sq ft) |
| Wavelengths | X-ray / γ-ray |
| Resolution | 2 arcsec up to 100 keV 7 arcsec up to 400 keV 36 arcsec above 1 MeV |
|
|
|
Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI, originally High Energy Solar Spectroscopic Imager or HESSI) is a NASA solar flare observatory. It is the sixth mission in the Small Explorer program, selected in October 1997 and launched on 5 February 2002. Its primary mission is to explore the physics of particle acceleration and energy release in solar flares.
HESSI was renamed to RHESSI on 29 March 2002 in honor of Reuven Ramaty, a pioneer in the area of high energy solar physics. RHESSI is the first space mission named after a NASA scientist. RHESSI was built by Spectrum Astro for Goddard Space Flight Center and is operated by the Space Sciences Laboratory in Berkeley, California. The principal investigator from 2002 to 2012 was Robert Lin, who was succeeded by Säm Krucker.
RHESSI is designed to image solar flares in energetic photons from soft X-rays (~3 keV) to gamma rays (up to ~20 MeV) and to provide high resolution spectroscopy up to gamma-ray energies of ~20 MeV. Furthermore, it has the capability to perform spatially resolved spectroscopy with high spectral resolution.
Researchers believe that much of the energy released during a flare is used to accelerate, to very high energies, electrons (emitting primarily X-rays) and protons and other ions (emitting primarily gamma rays). The new approach of the RHESSI mission is to combine, for the first time, high-resolution imaging in hard X-rays and gamma rays with high-resolution spectroscopy, so that a detailed energy spectrum can be obtained at each point of the image.
This new approach will enable researchers to find out where these particles are accelerated and to what energies. Such information will advance understanding of the fundamental high-energy processes at the core of the solar flare problem.
The primary scientific objective of RHESSI is to understand the following processes that take place in the magnetized plasmas of the solar atmosphere during a flare:
These high-energy processes play a major role at sites throughout the universe ranging from magnetospheres to active galaxies. Consequently, the importance of understanding these processes transcends the field of solar physics; it is one of the major goals of space physics and astrophysics.
...
Wikipedia