Earth observation satellite GISAT-1 slated for August 12 launch, says ISRO

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Chennai: The Indian Space Research Organization (ISRO) has announced the date for its second rocket launch of the year 2021. Earth Observation satellite GISAT-1, also known as EOS-3, will be launched on Thursday, August 12 at 5:43 am, said the space agency. However, the tentative launch time is subject to change depending on the weather conditions.

According to ISRO, GISAT-1 is meant to provide near-real-time imaging of large region of interest at frequent intervals, quick monitoring of natural disasters, episodic events and also obtain spectral signatures for agriculture, forestry, mineralogy, disaster warning, cloud properties, snow and glaciers and oceanography.

The GSLV Mk2 rocket would be carrying GISAT-1, an agile earth observation satellite, that is meant to be placed in geostationary orbit about 36,000 km from the earth’s equator. The orbit is typically meant for communication satellites that have to cover a large swathe of land. A satellite in geostationary orbit would be in sync with the rotation cycle of the earth (24 hours) and it would appear to be stationary when seen from the earth. It is said that three aptly positioned geostationary satellites can cover pretty much all of Earth’s surface.

Conventionally, such earth observation satellites are placed in low-earth orbit, between 500 and 2000 km, to ensure high-resolution imagery, better capabilities. However, it is pertinent to note that ISRO’s satellite is to be placed 36,000 km away from the earth’s surface. Being placed in a circular orbit would also mean that the 2268 kg GISAT-1 will be beyond the range of anti-satellite missiles.

Quoting former ISRO Chairman Dr Madhavan Nair and former URSC Director Dr Mylswamy Annadurai, Zee Media had earlier reported that, despite GISAT’s placement in far-away orbit, it can use different types of imaging technologies to provide constant monitoring of a region of interest, calamity and weather pattern.

In case a cyclone or similar rapidly-changing weather pattern is being continually monitored by GISAT-1, then the satellites in low earth orbit can also be tasked to get higher resolution imagery from a relatively closer range. They also added that being an agile satellite, it can rotate on an east-west or north-south axis to enable imaging of a specific region. In layman’s terms, it’s like tilting a handheld camera and mildly moving it for getting the best shot.

GISAT was originally meant to be launched in March 2020, but it was called off owing to technical reasons. After the pandemic-related delays, the launch was scheduled for March 2021, when it got further delayed due to some technical issues in the satellite.

The website of ISRO’s spaceport Satish Dhawan Space Centre has earlier posted that the agency had two launches in two months - a GSLV Mk2 mission in August and a PSLV mission in September.

During the second wave of the pandemic in India, ISRO suspended its launch activities, but the agency contributed to the COVID-19 fight by ramping up production of liquid oxygen for hospitals, re-purposing its storage tanks for oxygen, developing low-cost ventilators etc.