SROSS-C2 or Stretched Rohini Satellite Series C2 was a satellite developed by the

Indian Space Research Organisation The Indian Space Research Organisation (ISRO ) is India's national List of government space agencies, space agency, headquartered in Bengaluru, Karnataka. It serves as the principal research and development arm of the Department of Space (DoS), ...

. It conducted research on

Gamma Ray Burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are extremely energetic events occurring in distant galaxies which represent the brightest and most powerful class of explosion in the universe. These extreme electromagnetic emissions are second ...

s in

Low Earth Orbit A low Earth orbit (LEO) is an geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial object ...

. It was launched on 4 May 1994 using an ASLV rocket from

Satish Dhawan Space Centre Satish Dhawan Space Centre – SDSC (formerly Sriharikota Range – SHAR) is the primary spaceport of the Indian Space Research Organisation (ISRO), located in Sriharikota, Tirupati district, Andhra Pradesh. The spaceport is located on an isl ...

. The first two satellites in the

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

series failed to attain orbit. The third one attained a much lower orbit than planned. SROSS-C2 is thus the first fully successful, and the last satellite in the series.

Design

Magnetic Torquer and Magnetic Bias Control Sensors, Magnetometer, Twin-slit

Sun sensor A Sun sensor is a navigational instrument used by spacecraft to detect the position of the Sun. Sun sensors are used for Spacecraft attitude control, attitude control, solar array pointing, gyroscope, gyro updating, and safe mode (spacecraft), fai ...

and Temperature sensors helped the satellite to be spin stabilized. This was done using monopropellant,

Hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydraz ...

based with six thrusters each capable of delivering 1 Newton force. It has an octagonal structure. Body mounted and deployable solar panels provided 45 watts of power, with NiCd battery of 12-amp hours. S-band and VHF bands were used for communication. The SROSS C2 satellite also used an RCA CDP1802 microprocessor for the GRB experiment.

Science data

Diagram of the SROSS 3 gamma-ray burst detectors

The

gamma ray A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists o ...

burst experiments on board the satellite are an improved version of the payload on the SROSS-C satellite. The improvements include increased on-board memory and a better measurement of the background spectra after a burst event. These modifications 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 The InterPlanetary Network (IPN) is a group of spacecraft equipped with gamma ray burst (GRB) detectors. By timing the arrival of a burst at several spacecraft, its precise location can be found. The precision for determining the direction of a G ...

. The mission also contained a Retardating Potential Analyser (RPA). It measured temperature, density and characteristics of electrons in the Earth's

ionosphere The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays ...

, mainly in situ measurements of F-region ionospheric plasma. The instrument consisted of an electron RPA, ion RPA and a potential probe (PP), designed and developed at the National Physical Laboratory,

New Delhi New Delhi (; ) is the Capital city, capital of India and a part of the Delhi, National Capital Territory of Delhi (NCT). New Delhi is the seat of all three branches of the Government of India, hosting the Rashtrapati Bhavan, New Parliament ...

. It simultaneously sampled electron and ion plasma in the altitude range of 420–620 km for more than half a

solar cycle The Solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a periodic 11-year change in the Sun's activity measured in terms of Modern Maximum, variations in the number of observed sunspots on the Sun ...

from minima to maxima of the 23rd solar cycle activity. Measurements were made in a higher orbit for a limited period of two months during the initial phase, while the satellite

apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

was at 930 km keeping the

perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

same.

References

{{reflist Space research Satellites of India Spacecraft launched in 1994