The Stretched Rohini Satellite Series (SROSS) are a series of satellites developed by the Indian Space Research Organization as follow ons to the Rohini Satellites  for conducting astrophysics, Earth Remote Sensing

Remote sensing

Remote sensing is the acquisition of information about an object or phenomenon, without making physical contact with the object. In modern usage, the term generally refers to the use of aerial sensor technologies to detect and classify objects on Earth by means of propagated signals Remote sensing...

, and upper atmospheric monitoring experiments as well as for new and novel application-oriented missions . These satellites were the payload of the developmental flights of the Augmented Satellite Launch Vehicle.

SROSS A And SROSS B

The first 2 satellites in the series did not make it into orbit due to launch vehicle failure. SROSS-A carried two retro-reflectors for laser tracking. SROSS-B carried two instruments; a West German

West Germany

West Germany is the common English, but not official, name for the Federal Republic of Germany or FRG in the period between its creation in May 1949 to German reunification on 3 October 1990....

 Monocular Electro Optical Stereo Scanner (MEOSS) and ISRO's 20-3000keV Gamma-ray Burst Experiment (GRB).

SROSS C

The third, SROSS 3 (also known as SROSS C), successfully attained an orbit on 20 May 1992.The GRB monitored celestial gamma ray bursts in the energy range 20-3000 keV. SROSS C and C2 carried a gamma-ray burst (GRB) experiment and a Retarded Potential Analyzer (RPA) experiment. The GRB experiment operated from 25 May 1992 until reentry on 14 July 1992. The instrument consisted of a main and a redundant CsI(Na) scintillator operating in the energy range 20-3000 keV. The crystals were 76 mm (main) and 37 mm (redundant) in diameter. Each had a thickness of 12.5 mm. A 'burst mode' was triggered by the 100-1024 keV count rate exceeding a preset limit during a 256 or 1024 ms time integration. In this mode, 65 s of temporal and 2 s of spectral data prior to the trigger are stored, as well as the subsequent 16 s of spectral data and 204 s of temporal data. The low resolution data consists of 2 energy channels (20-100 keV and 100- 1024 keV) from 65 s before the trigger to 204 s after the trigger in 256 ms integrations. The 20-1024 keV rates are also recorded with a 2 ms resolution for 1 s prior to 1 s after trigger and a 16 ms resolution for 1s prior to 8 s after the trigger. Energy spectra are conducted with a 124 channel PHA. Four pre-trigger spectra and 32 post-trigger spectra are recorded for every burst with a 512 ms integration time. The RPA measured temperature, density and characteristics of electrons in the Earth's ionosphere.

SROSS C2

SROSS-C2 was launched on 4 May 1994.The Gamma Ray

Gamma ray

Gamma radiation, also known as gamma rays or hyphenated as gamma-rays and denoted as γ, is electromagnetic radiation of high frequency . Gamma rays are usually naturally produced on Earth by decay of high energy states in atomic nuclei...

 The GRB experiments on board SROSS-C2 are an improved version of the GRB payload flown successfully on the SROSS-C satellite. The improvements include enhancements of the on-board memory and a better measurement of the background spectra after a burst event. These improvements led to the discovery of twelve candidate events detected up to 15 February 1995, out of a total of 993 triggers. The SROSS-C2 spacecraft is one of the satellites included in the Interplanetary Network

InterPlanetary Network

The InterPlanetary Network is a group of spacecraft equipped with gamma ray burst detectors. By timing the arrival of a burst at several spacecraft, its precise location can be found. The farther apart the detectors, or the greater the timing precision of each detector, the more precise the GRB...