| Satellites: : Aryabhata | APPLE | INSAT-1
| INSAT-2
| INSAT-3
| Bhaskara
| IRS | Rohini Launcher
: : SLV
| PSLV | ASLV | GSLV
(Launched by Indian launch
vehicle SLV-3 )
Rohini 1A :
Launching tried by
SLV-3 rocket, on 10 August, 1979, made by India,
from Shriharikota. Rocket failed.
Rohini 1B
Launch Date : July 18,
1980
Weight : 35 kg
Orbit : 300 km x 900 km elliptical orbit
(97 minutes period)
Lauched by : India, SLV-3 rocket
Objectives : The satelite provided data on
the fourth stage performance and ranging.
Rohini-2
Launch Date : May 30, 1981
Weight : 35 kg
Lauched by : India, SLV-3 (D-1) rocket
Orbit : 300 km x 900 km elliptical orbit
(97 minutes period)
Objectives : Carried a Land Mark sensor
payload whose solid state camera performed to
specifications. The satellite re-entered the
earth's atmosphere nine days after lauch on
account of the launch vehicle's injecting the
satellite into a lower than expected altitude.
However the orbit achieved was 186x418km instead
of the planned 296x834km, leading to re-entry
after eight days.
Rohini-3
Launch Date : April 17,
1983
Weight : 35 kg
Lauched by : India, SLV-3 (D-2)rocket
Orbit : 300 km x 900 km elliptical orbit
(97 minutes period)
Objectives : The Smart Sensor Camera was
the primary payload on board the satellite. It
was operated for over five months and sent more
than 2500 pictures frames in both visible and
infrared bands for identification of landmarks
and altitude and orbit refinement. The camera had
on-board processing capability to use the data
for classifying ground features like water,
vegetation, bare land, clouds and snow. After
completing all its mission goals, RS-D2 was
closed down on Sept. 24, 1984. It re-entered
orbit on 19 April 1990.
SROSS -
Stretched Rohini Satellite Series
ISRO developed the Stretched
Rohini Satellite Series (SROSS) for conducting
various scientific experiments as well as for new
and novel application-oriented missions. The
first two satellites in the series did not make
it into orbit due to launch vehicle failure. The
third, SROSS-3, successfully attained an orbit on
20 May 1992.
Although they decayed rapidly,
the orbital parameters were initially; apogee was
430km, perigee was 255km, and the orbital
inclination was 46º. The satellite spin period
was 10.6 sec. The satellite carried a gamma-ray
burst (GRB) experiment and a retarded potential
analyzer (RPA) payload. It re-entered orbit on 14
July 1992.
Instrumentation:
The gamma-ray burst experiment was operated from
25 May 1992 until re-entry 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 76mm (main)
and 37mm (redundant) in diameter. Each had a
thickness of 12.5mm.
A 'burst mode' was triggered by
the 100-1024 keV count rate exceeding a preset
limit during a 256 or 1024 milliseconds time
integration. In this mode, 65 seconds of temporal
and 2 seconds of spectral data prior to the
trigger are stored, as well as the subsequent 16
seconds of spectral data and 204 seconds of
temporal data.
The low resolution data consists
of two energy channels (20-100 keV and 100-1024
keV) from 65 seconds before the trigger to 204
seconds after the trigger in 256 milliseconds
integrations. The 20-1024 keV rates are also
recorded with a two milliseconds resolution for
one second, prior to a one second after trigger
and a 16 milliseconds resolution for one second
prior to 8 second 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
millseconds integration time.
Science:
During the mission lifetime, 53 triggers
occurred. Most of these, as expected, were false.
There were eight candidates for real bursts. One
event, on 22 of June was also seen by CGRO and is
believed real. Two other events could be real, as
CGRO was not recording data at the time and so
could not corroborate their occurrence.
Sources and
Resources
- Other source : www.bharatrakshak.com
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