GISAT-1: India’s ‘Eye In The Sky’ To Be Launched In Aug 2021: ISRO

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The News

Indian Space Research Organisation (ISRO) Chief K. Sivan has told that ISRO is working towardslaunching India’s GISAT-1, an Earth observation satellite, in August 2021.
Apparently, launch is scheduled at 5:43 am on August 12th, according to an internal deadline, however official launch dates have not been announced.
This will be ISRO’s second launch of 2021, after Brazilian Amazonia-1 was injected into orbit by a PSLV rocket in February.

GISAT-1 will have
- 700 mm Ritchey–Chrétien telescope
- Array detectors in Visible and Near-InfraRed (VNIR), and Short Wave-InfraRed (SWIR) bands
- Electronically steerable, phased array antenna
- High agility, jitter-free platform

GISAT-1 will image in multi-spectral and hyper-spectral bands to provide near real-time pictures of large areas of the country, under cloud-free conditions every 5 minutes and entire Indian landmass image every 30 minutes at 42 m spatial resolution.
GISAT-1 is meant to provide near-realtime imaging of large regions 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 & glaciers, and oceanography.

Conventionally, Earth-observation satellites are placed in low-earth orbit (between 500 and 2000kms), to ensure high resolution imagery and better capabilities & communication satellites are placed in GEO.
However, GISAT is going to be placed 36,000kms away from the earth’s surface in the Geostationary Orbit (GEO).
Despite GISAT’s placement in a far-away 36,000km orbit, it can use different types of imaging technologies to provide constant monitoring of a region of interest/calamity/weather pattern.
LEO satellites can make a pass only once every 110 minutes (appx) to click pictures and collect data, GISAT-1 can take large area pictures every 5 minutes and of entire landmass every 30 minutes.

GISAT-1 was originally meant to be launched in March 2020, but the launch was called off for technical reasons.
After the pandemic-related delays, the launch was pushed to March 2021.
However, during the second wave of the pandemic in India, ISRO suspended its launch activities and it 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.