US banned Isro's GSLV in 1992; now Nasa revives it

The US National Aeronautics and Space Administration has joined hands with the Indian Space Research Organisation for the NASA-ISRO Synthetic Aperture Radar or NISAR satellite, a joint mission between the US space agency and the Indian space agency to develop the world's most expensive earth imaging satellite.

Ironically, NISAR, scheduled to launch in 2021 from India, will be placed into the orbit using ISRO's Geo-synchronous Satellite Launch Vehicle (GSLV) - the same rocket for whose cryogenic engine technology the US put sanctions on India some 25 years back.

In 1992, the US under President George Bush had slapped sanctions on ISRO and prevented Russia from sharing cryogenic engine technology with the Indian space agency on the ground that India could use it to make missiles.

Following the US sanctions, Russia backed out of the deal and ISRO started the Cryogenic Upper Stage Project in April 1994 and began developing its own cryogenic stage.

Over two decades later NASA has joined hands with ISRO to co-develop the world's most expensive earth imaging satellite that will cost the two countries over $1.5 billion.

ISRO and NASA are now building the 2,200kg NISAR satellite, which will provide a detailed view of the earth using advanced radar imaging.

It is being designed to observe and take measurements of some of the planet's complex processes, including ecosystem disturbances, ice-sheet collapse and natural hazards.

NASA became interested in partnering ISRO when the Indian space agency in April 2012 launched the country's first indigenous radar imaging satellite (Risat-1), which enabled imaging of the earth's surface during day and night under all weather conditions.

The negotiations went on for two years but the formal agreement for NISAR satellite happened when Prime Minister Narendra Modi signed a declaration with former US President Barack Obama during his visit to the US in 2014, The Times of India reported. The objective behind the collaboration was to use the satellite for the "benefit of humanity" as the mapping data from this satellite will be available for all.

Currently, the Ahmedabad-based Space Application Centre (SAC) is flight testing the "mini version" of the radar satellite over the city skies. The "mini radar" developed by SAC has been fixed on a Beechcraft Super King B 200 owned by ISRO for the flight-testing primarily to 'understand weather and geographical conditions'.

SAC director Tapan Misra said, "We are testing the radar by taking images from about 8km above the sea level. The same area will be further studied by scientists from the ground level to understand the radar's accuracy level."

He added, "For ground level data analysis, we are roping in NGOs, academic institutes, government departments and people with scientific expertise. This process of aerial data analysis will continue in Gujarat for three months until the crop season ends. We plan to conduct the same aerial-cum-ground exercise for three years in 39 places of the country, including over the Himalayan glaciers, Ganga, Sundarbans, Rann of Kutch, Andhra, Kerala and Karnataka, to study the geological changes in forests, vegetation, rivers and glaciers."