"NISAR will be the first satellite mission to use two
different radar frequencies (L-band and S-band) to measure changes in our
planet's surface less than a centimetre across", according to NASA.
NASA and Bengaluru-headquartered Indian Space Research
Organisation (ISRO) signed a partnership on September 30, 2014, to collaborate
on and launch NISAR.
The mission is targeted to launch in early 2022 from ISRO's
Sriharikota spaceport in Andhra Pradesh's Nellore district, about 100 kms north
of Chennai. NASA is providing the mission's L-band SAR, a high-rate
communication subsystem for science data, GPS receivers, a solid-state
recorder, and payload data subsystem.
ISRO is providing the spacecraft bus, the S-band radar, the
launch vehicle, and associated launch services for the mission, whose goal is
to make global measurements of the causes and consequences of land surface
changes using advanced radar imaging.
The S-band SAR payload of NISAR satellite mission was
flagged off by the Secretary in the Department of Space and ISRO Chairman K
Sivan on March 4 through virtual mode.
The payload has been shipped from ISRO's Ahmedabad-based
Space Applications Centre (SAC) to NASA's Jet Propulsion Laboratory (JPL) at
Pasadena in the US for integration with the latter's L-band SAR payload, an
ISRO statement said.
"NISAR would provide a means of disentangling highly
spatial and temporally complex processes ranging from ecosystem disturbances to
ice sheet collapses and natural hazards including earthquakes, tsunamis,
volcanoes, and landslides", ISRO said.
NASA added that the mission will measure Earth's changing
ecosystems, dynamic surfaces, and ice masses, providing information about
biomass, natural hazards, sea level rise, and groundwater, and will support a
host of other applications.
"NISAR will observe Earth's land and ice-covered
surfaces globally with 12-day regularity on ascending and descending passes,
sampling Earth on average every six days for a baseline three-year
mission", NASA said on the mission's website.
"This allows the mission to observe a wide range of Earth
processes, from the flow rates of glaciers and ice sheets to the dynamics of
earthquakes and volcanoes". NISAR uses a sophisticated
information-processing technique known as SAR to produce extremely
high-resolution
images.
Radar penetrates clouds and darkness, enabling NISAR to
collect data day and night in any weather. The instrument's imaging swath the
width of the strip of data collected along the length of the orbit track is
greater than 150 miles (240 kilometres), which allows it to image the entire
Earth in 12 days, it was stated.
Over the course of multiple orbits, the radar images will
allow users to track changes in croplands and hazard sites, as well as to
monitor ongoing crises such as volcanic eruptions. The images will be detailed
enough to show local changes and broad enough to measure regional trends.
As the mission continues for years, the data will allow for
better understanding of the causes and consequences of land surface changes,
increasing our ability to manage resources and prepare for and cope with global
change, according to NASA.
"NASA requires a minimum of three years of global
science operations with the L-band radar and ISRO requires five years of
operations with the S-band radar over specified target areas in India and the
Southern Ocean", it said.