Q/ How important is the NISAR mission and what new capabilities can it offer?
A/ The Earth is constantly changing in small and monumental ways, and NISAR will provide a dynamic, three-dimensional view of nearly the full breadth of these changes. The satellite is designed to detect the movement of land and ice surfaces down to the centimetre, and will also be able to map how vegetation in forests, wetlands, and agricultural regions are responding to evolving weather and climate conditions.
Earlier, there have been airborne missions that use similar synthetic aperture radar (SAR) to collect the same kinds of data, but generally speaking, a radar flown aboard an airplane cannot cover the vast areas of the planet’s surface that a space-borne instrument can. NISAR will be able to cover nearly all of Earth’s land and ice surfaces twice every 12 days, and it can do so in all weather conditions, day or night.
The NISAR science payload is the most sophisticated radar system ever to be launched as part of a science mission NASA has been involved in. The NISAR science payload consists of two radars, the L-band and the S-band. By combining measurements from two radars that operate at different frequencies, the mission will be able to observe changes in the Earth over a wider range of environments than either instrument could do alone. Due to its broad coverage of the planet, NISAR will produce about 80 terabytes of data per day (80,000GB)―the most data ever released by an Earth science mission that NASA has been involved in.
Q/ What are NISAR’s applications?
A/ There are many applications, and we have really only scratched the surface in terms of understanding its potential. For instance, NISAR will provide critical information to inform our response to urgent challenges posed by climate change. By improving estimates of the carbon exchange between the atmosphere and plant communities in forest and agricultural regions, it will help scientists improve their climate models.
Additionally, NISAR will also measure the motion and melting of sea ice and ice sheets in the planet’s polar regions, which will improve our understanding of sea level rise, and it will identify changes in the shape of coastlines, helping us gauge the impacts of the rising ocean on coastal ecosystems and communities.
NISAR data will help communities prepare for natural and human-caused hazards, as well as respond to and recover from these events. For example, it will be able to detect subtle, slow-moving changes in the shape and elevation of the land surface that can precede natural hazards such as earthquakes, landslides, and volcanic unrest. Then, following such events, NISAR data would be used to assess damage on the ground, providing disaster response agencies with actionable information within hours or days.
Q/ How was this mission conceived?
A/ The idea grew out of the US National Academy of Science’s 2007 Earth Science Decadal Survey, which expressed a need for more data and insight on Earth’s ecosystems, the deformation of its land surfaces, and changes in its ice sheets and sea ice. NASA and ISRO [were both interested]. So, in 2014 the agencies signed a partnership agreement to develop and launch NISAR.