Abstract:
Abstract—The National Aeronautics and Space Administration
(NASA) in the United States and the Indian Space Research
Organisation (ISRO) are developing an Earth-orbiting science
and applications mission that will exploit synthetic aperture
radar to map Earth’s surface every 12 days, persistently on
ascending and descending portions of the orbit, over all land and
ice-covered surfaces. The mission’s primary objectives will be to
study Earth land and ice deformation, and ecosystems, in areas
of common interest to the US and Indian science communities.
This single spacecraft solution with an L-band (24 cm
wavelength) and S-band (10 cm wavelength) radar has a swath
of over 240 km at fine resolution, using full polarimetry where
needed, uses a reflector-feed system whereby the feed aperture
elements are individually sampled to allow a scan-on-receive
(“SweepSAR”) capability at both L-band and S-band. This
design is in contrast to recent concepts towards large
constellations of smaller radar satellites, and is driven by the
science requirements for complete coverage over the 12-day
repeat cycle, using repeat pass interferometry and polarimetry
to measure deformation and surface properties. A single
spacecraft with enough aperture, power, duty cycle, and
downlink capacity was determined to be a more practical and
implementable solution that multiple smaller spacecraft. The
use of a single large aperture reflector for both the L- and Sband
radars enables both to have comparable performance,
leading to overall development and operational efficiencies.
