Q. With reference to the NASA-ISRO Synthetic Aperture Radar (NISAR) satellite, consider the following statements:
1.NISAR will be the first radar imaging satellite to use dual frequencies for observing Earth’s surface.
2.NISAR will cover the entire Earth every 12 days.
3.S-band Synthetic Aperture Radar (SAR) of the satellite is capable of penetrating in depth through vegetation, snow, and soil to capture images of surface changes and movements.
How many of the statements given above are correct?
Explanation –
Statements 1 and 2 are correct. The NASA-ISRO Synthetic Aperture Radar (NISAR) satellite is a joint venture between NASA and ISRO, designed to observe Earth’s surface with high precision. It features dual-frequency radars: the L-band (provided by NASA) and the S-band (developed by ISRO). NISAR will be the first radar imaging satellite to utilize dual frequencies, specifically the L-band and S-band, to observe Earth’s surface. This dual-frequency approach allows for detailed observations of Earth’s surface, including areas covered by dense vegetation or cloud cover. NISAR satellite will map nearly the entire Earth’s land and ice surfaces every 12 days. It will scan the Earth twice every 12 days in ascending and descending passes, and can operate day and night, even through clouds.
Statement 3 is incorrect. While the S-band SAR on NISAR can penetrate light vegetation and is useful for certain applications like monitoring soil moisture and slight vegetation, it does not have the capability to penetrate through vegetation, snow, and soil as deeply as the L-band SAR. The L-band, with its longer wavelength, is more effective for deeper penetration through these materials.
Source: The Hindu
