Earlier this week, the Indian Space Research Organisation (Isro) received the Nasa-Isro Sar (Nisar) satellite from US space agency Nasa, “setting the stage for final integration of the Earth observation satellite,” tweeted the US Consulate in Chennai. This is a major milestone for the US-India space collaboration plans.
The final integration will be carried out at the U.R. Rao Satellite Centre in Bengaluru, and Isro is looking to launch the satellite in 2024 from the Satish Dhawan Space Centre in Sriharikota, according to the Nasa website.
Optimized for understanding Earth’s topography and managing natural resources, Nisar is a low-earth orbit observatory jointly developed by Nasa and Isro. Nisar is an acronym for the Nasa-Isro Sar mission, a one of its kind collaboration between the two space agencies, that aims to measure Earth’s changing ecosystems, and surfaces, including ice-covered ones, to provide information about natural hazards and rising sea levels.
Nisar will map the entire globe in 12 days and provide spatially and temporally consistent data to better understand Earth's effects of climate change. It is the first satellite mission to collect radar data in two microwave bandwidth regions, called the L-band and the S-band, and measure changes in Earth’s surface less than a centimetre across, the Nasa website explains. The Sar operates with the Sweep Sar technique to provide high-resolution data, according to Isro. It can penetrate clouds and darkness, enabling Nisar to collect data all day and throughout the year.
How can it help?
Human activities in high-risk areas that are prone to hazards such as sea level change, land subsidence, tsunamis, volcanoes, earthquakes and landslides are causing thousands of deaths and costing billions of dollars annually. Better predictions – leading to improved mitigation – can help save the planet from such events. Nisar can track even subtle changes which will help improve disaster response.
Furthermore, Nisar's data will be open access, allowing policymakers across the world to “use them for scientific, societal and commercial goals.” It will also save pre-disaster images that can be accessed to quickly understand how the disaster occurred, leading to the development of “actionable applications” such as water resource monitoring.
A survey by the US National Academy of Science of Earth in 2017, called the Earth Science Decadal Survey, outlined observation priorities for Nasa for the next decade. One of the main objectives was collecting data and enhancing insight into three Earth science domains: ecosystems, deformation of Earth's crust and cryospheric sciences. Isro-Nasa’s partnership emerged as a response to this survey, according to the US space agency.
On 30 September, 2014, Nasa and Isro signed a partnership to collaborate on and launch Nisar. While Nasa brought in the “L-band synthetic aperture radar, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder and payload data subsystem,” according to its official website, Isro is providing the “spacecraft bus, the S-band radar, the launch vehicle and associated launch services.”
Along with monitoring the use of natural resources, and Earth’s changing surfaces, Nisar will keep an eye at changes in surface motions that can identify and predict catastrophic events, determine how varying biomass contributes to the global carbon budget, help better understand land use, shed light on how climate and ice masses are linked and measure changes in permafrost and surface melting, track flow rates of glaciers, and monitor changes in groundwater in vulnerable arid regions to provide insight into the changes occurring below the ground and its consequences.