Chennai, No 28 (UNI) The Indo-US joint NISAR Mission has entered the science phase
with the successful deployment of 12 m Radar Antenna after the commissioning phase
was completed.
The Indian Space Research Organisation (ISRO) today said after the successful launch
of NASA-ISRO Synthetic Aperture Radar (NISAR) satellite (with a mission life of 5 years)
onboard GSLV-F16 on July 30 into a 747 Circular Polar Syn synchronous Orbit, the 12m
diameter Antenna reflector has been successfully deployed.
The 12-meter diameter antenna reflector plays a key role for both ISRO’s S-Band and
NASA’s L-Band Synthetic Aperture Radar (SAR) Payload.
The antenna was launched in a stowed condition on a 9m long boom, which was tucked
closed to the satellite. The antenna and the 9m boom was developed by NASA.
The unfolding of the joints of the boom commenced on August 9, 2025 and was carried
out over a period of five (05) days (Wrist, Shoulder, Elbow and Root deployments). The
reflector assembly mounted on the end of the boom was deployed successfully on
August 15, 2025 and the performance of the antenna systems are satisfactory.
The entire operations were carried out from ISRO Telemetry Tracking and Command
Network (ISTRAC), ISRO with the support of Jet Propulsion Laboratory/NASA.
After the Launch Phase, Deployment Phase, Commissioning Phase, it has now emtered
the Science Phase.
The science operations phase, which began at the end of commissioning phase, would
extend till the end of mission life.
During this phase, the science orbit will be maintained via regular maneuvers, scheduled
to avoid or minimize conflicts with science observations. Extensive calibration and validation
(CalVal) activities will take place. The observation plan for both L and S-band instruments,
along with engineering activities (e.g., maneuvers, parameter updates, etc.), will be generated
pre-launch via frequent coordination between JPL and ISRO.
On the completion of Commissioning phase, ISRO said since the first acquisition on
August 19, 2025, NISAR S-Band SAR is regularly imaging over Indian Landmass and
Global Calibration-Validation sites in various payload operating configurations.
Reference targets such as Corner reflectors were deployed around Ahmedabad, Gujarat
and a few more locations in India for calibration of the images.
The Data acquired over Amazon rainforests were also used for calibration of spacecraft
pointing and images. Based on this, payload data acquisition parameters were fine tuned
resulting in high quality images.
Initial analysis by scientists and engineers revealed the potential of S-Band SAR data
for various targeted science and application areas like agriculture, forestry, geo-sciences,
hydrology, Polar/Himalayan ice/snow and oceanic studies.
The first image of S-band SAR acquired on August 19, 2025 captures the fertile Godavari
River Delta in Andhra Pradesh, India. Various vegetation classes like mangroves, agriculture,
arecanut plantations, acquaculture fields, etc are clearly seen in the image.
The image highlights NISAR’s S-Band SAR ability to map river deltas and agricultural
landscapes with precision.
In the 100th day of NISAR in-orbit, the S-SAR images are released to the public by
ISRO Chairman and Secretary DOS Dr V Narayanan.
With this, the commencement of science phase has also been announced.
NISAR is the first of its kind mission, jointly developed by ISRO and NASA.
It is an L and S-band, global, microwave imaging mission, with capability to acquire
fully polarimetric and interferometric data.
The unique dual-band Synthetic Aperture Radar of NISAR employs advanced, novel
SweepSAR technique, which provides high resolution and large swath imagery.
NISAR will image the global land and ice-covered surfaces, including islands, sea-ice
and selected oceans every 12 days.
NISAR mission’s primary objectives are to study land and ice deformation, land
ecosystems, and oceanic regions in areas of common interest to the US and
Indian science communities.
NISAR mission will help to measure the woody biomass and its changes, track
changes in the extent of active crops, understand the changes in wetlands’ extent
map Greenland’s and Antarctica’s ice sheets, dynamics of sea ice and mountain
glaciers, characterize land surface deformation related to seismicity, volcanism,
landslides, and subsidence and uplift associated with changes in subsurface
aquifers, hydrocarbon reservoirs, etc.
UNI GV 1800