BENGALURU: The Indian Space Research Organisation (ISRO) on Wednesday successfully launched the NASA-ISRO Synthetic Aperture Radar (NISAR) at 5.40 pm from Satish Dhawan Space Centre (SDSC), Sriharikota High Altitude Range (SHAR), marking the 102nd launch from here.
This is the first collaborative mission between ISRO and NASA – costing $1.5 billion and with a mission life of five years – in which the unique satellite’s dual-band Synthetic Aperture Radar (SAR) will employ advanced, novel SweepSAR technique, to provide high-resolution and large swath imagery. The 2,393-kg NISAR satellite will image the global land and ice-covered surfaces, including islands, sea ice and selected oceans every 12 days.
The lift-off of the 51.7-metre-tall GSLV F-16, carrying the 2,393-kg NISAR satellite, took place at the end of a 27.30-hour countdown from SDSC-SHAR’s second launch. Precisely 19 minutes after lift-off, ISRO’s launcher GSLV F-16 injected NISAR into a Sun Synchronous Polar Orbit (SSPO) at an orbit altitude of 747 km – the first time that ISRO’s GSLV (Geostationary Satellite Launch Vehicle) has placed a satellite in a sun-synchronous orbit, as all earlier GSLV launches had placed satellites in Geosynchronous Transfer Orbit (GTO). ISRO Chairman and Secretary, Department of Space, V Narayanan, said after the successful launch and satellite’s orbital insertion, “All the vehicle system performances were quite normal as expected and as predicted. Today, we achieved the intended orbit. Actually, we have got an orbit with a dispersion (deviation from desired orbit) of less than 3 km, as against the permissible level of 20 km... all parameters are as expected.” He added that GSLV F-16’s cryogenic upper stage corrections and a host of mission simulations were carried out very systematically and meticulously.
Chaitra Rao, Project Spacecraft Director, NISAR, said that as per schedule, NISAR’s solar panels were deployed and the satellite was appropriately titled. The first 90 days of the mission will be dedicated to commissioning, or In-Orbit Checkout (IOC), to prepare NISAR for science operations. Commissioning is divided into sub-phases of initial checks and calibrations of mainframe elements followed by NASA’s Jet Propulsion Laboratory (JPL) engineering payload and instrument checkout.
NISAR’s science operations phase will begin at the end of commissioning and will extend till the end of mission life. During this phase, the science orbit will be maintained via regular manoeuvres, scheduled to avoid or minimise conflicts with science observations. Extensive calibration and validation (CalVal) activities will take place. The uniqueness of this satellite is that it carries two major payloads, L & S-band SAR, and is a global, microwave imaging satellite with the capability to acquire fully polarimetric and interferometric data. The S-band radar system, data handling and high-speed downlink system, the spacecraft and the launch system are developed by ISRO. The L-band radar system, high-speed downlink system, the solid-state recorder, GPS receiver, the 9m boom hoisting the 12m unfurlable reflector are delivered by NASA.
Prakash Chauhan, Director, National Remote Sensing Centre, said after the SARs start working, the NRSC’s Shadnagar centre will receive 8 terabyte data, and NASA’s JPL will receive 35 terabyte, while the Antarctica Centre will also play a crucial role in receiving and disseminating data. Deputy Associate Administrator at NASA, Casey Swails, said: “This mission is truly a pathfinder, not just in regards to our technical collaborations because those are truly incredible, but earth science mission is one-of-a-kind, which really shows the world what the two nations can do. But more than that, it is really a pathfinder for the relationship-building across our two nations, building upon decades of collaborations that already existed.”