Bengaluru: ISRO is all set to launch the Earth observation satellite EOS-03 on the GSLV launcher from the second launch pad of Sriharikota. The launch is currently scheduled for 05.43 Hrs IST on 12 August 2021, and is called the GSLV-F10 EOS-03 mission.
The EOS-03, formerly known as the Geo Imaging Satellite-1 or GISAT-1, is a geo imaging or Earth observation satellite. It weighs approximately 2,268 kg, and will be inserted into an elliptical geosynchronous transfer orbit of 170 km x 36,297 km and an inclination of 19.4 degrees. The satellite will subsequently use its own propulsion system to reach its final circular geostationary orbit.
The GSLV rocket is flying with a 4m-wide Ogive-shaped payload fairing or nose cone, which will protect the payload at the very top of the rocket. The EOS-03 is the only payload on this mission, but the fairing is capable of accommodating larger and more payloads.
The satellite will be separated from the launcher just over 18 minutes after launch.
The EOS-03 is described by ISRO as India’s first state-of-the-art agile Earth observation satellite in a geostationary orbit. India currently has two Earth observation satellites in a geostationary orbit — the INSAT-3D (launched in 2013) and INSAT-3DR (launched in 2016), both for weather monitoring. India’s first indigenous experimental communication satellite, the Ariane Passenger Payload Experiment (APPLE) also occupied a geostationary orbit (GEO) for two years. It was launched in 1981 by the Ariane-1 from French Guyana.
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Monitoring natural disasters, security threats
In a geostationary orbit, a satellite moves in the direction of rotation of the Earth, 35,786 kilometres above the Earth’s equator, inclined parallel to the plane of the equator. The orbital period of the satellite is equal to the period of the rotation of the Earth, so the satellite appears in a fixed position in the sky at any time. Multiple satellites can occupy the same geostationary orbit in different locations.
The EOS-03 was known as the GISAT-1 until 2020, and was originally expected to fly on 5 March 2020 but was postponed due to “technical reasons”, and subsequently by the Covid pandemic’s first wave.
The satellite is expected to provide real-time, high-resolution imaging of a larger surface area at much frequent intervals. The satellite is expected to be used for monitoring natural disasters including cyclones, agriculture, forestry, mineralogy, monitoring cloud bursts and thunderstorms, sea level monitoring, snow and glacier cap monitoring, and any other “episodic events” or “short term events”, including threats to national security.
The satellite can image in near-infrared, short wave infrared, multi-spectral visible, and hyper-spectral visible spectral bands. It is expected to function for at least 10 years and can operate in cloud-free conditions.
This will be the 14th flight of the GSLV launcher, and the 8th flight with ISRO’s indigenous cryogenic upper stage (CUSP). This upper stage or part of the rocket is the last one to hold the payload after other stages are ejected or jettisoned over the Earth’s atmosphere, and uses a propellant combination made up of liquid oxygen and liquid hydrogen in two tanks.
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