NISAR (NASA-ISRO Synthetic Aperture Radar)
NISAR has been built by space agencies of the US and India under a partnership agreement signed in 2014.
The satellite is likely to be launched later this year from Satish Dhawan Space Centre into a near-polar orbit.
The satellite will operate for a minimum of three years.
It is a Low Earth Orbit (LEO) observatory.
It can fully map the earth twice a month, measure water bodies, greenery, snow cover, track agricultural changes, desertification, and aid in the study of climate-related issues
NISAR will be the first radar of its kind in space to systematically map Earth, using two different radar frequencies (L-band and S-band) to measure changes in our planet's surface less than a centimeter across.
Features
It is a 2,800 kilograms satellite consisting of both L-band and S-band Synthetic Aperture Radar (SAR) instruments, which makes it a dual-frequency imaging radar satellite.
While NASA has provided the L-band radar, GPS, a high-capacity solid-state recorder to store data, and a payload data subsystem, ISRO (Indian Space Research Organisation) has provided the S-band radar, the Geosynchronous Satellite Launch Vehicle (GSLV) launch system and spacecraft.
S band radars operate on a wavelength of 8-15 cm and a frequency of 2-4 GHz. Because of the wavelength and frequency, they are not easily attenuated. This makes them useful for near and far range weather observation.
It has a 39-foot stationary antenna reflector, made of a gold-plated wire mesh; the reflector will be used to focus “the radar signals emitted and received by the upward-facing feed on the instrument structure.
By using SAR, NISAR will produce high-resolution images.
SAR is capable of penetrating clouds and can collect data day and night regardless of the weather conditions.
NASA requires the L-band radar for its global science operations for at least three years. Meanwhile, ISRO will utilise the S-band radar for a minimum of five years.
Benefits
The U.S. will contribute the large deployable antenna.
It can fully cover the earth in approximately 14 to 15 days, in radar.
It can monitor the tectonic movements to centimetre accuracy.
It can measure water bodies accurately.
It can look at water stressing on the earth, wherever there is deficiency of water.
It can ground-penetrate to a certain depth.
It is capable of monitoring the vegetation cover and snow cover.
It, therefore, basically looks at the whole of the earth in terms of surface, water, greenery
We can study climate change-related issues, agricultural changes through patterns, yield, desertification and continental movements precisely.
So a lot of geological, agricultural and water-related observations can be obtained from the satellite
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