Countdown for the NISAR satellite launch to start in the afternoon

United News of India

4 days ago

Chennai, July 29 (UNI) The countdown for the July 30 launch of the first Indo-US joint earth observation satellite NASA ISRO Synthetic Aperture Radar (NISAR) is slated to start at about 2.10 pm on Tuesday, said ISRO officials.
'The 27-hour-and-30 minute countdown for the launch of the NISAR Mission is expected to start at 2.10 pm today (Tuesday),' an official of Indian Space Research Organisation (ISRO) said.
According to the official, during the countdown, fuel for the rocket will be filled while checking of the rocket systems will also be done.
India's Geosynchronous Satellite Launch Vehicle-F16 (GSLV-F16) carrying the NISAR weighing 2,393 kg will blast off at 5.40 pm from the second launch pad at the rocket port in Sriharikota, Andhra Pradesh.
Around 19 minutes after its lift-off, the 420-ton GSLV-F16, an expendable rocket will eject the NISAR satellite.
The satellite will be injected into a 747 km Sun Synchronous Polar Orbit (SSO) with an inclination of 98.4 degree, ISRO said.
Built at a cost of about $1.5 billion, NISAR's mission life will be five years.
The three-stage GSLV rocket standing 51.7 metre tall and weighing 420 ton is powered by a solid, liquid and cryogenic fuel -- liquid hydrogen and liquid oxygen.
The GSLV-F16 rocket is a three-staged vehicle. The first stage (GS1) is powered by a solid propellant motor having 139-ton propellant and four earth-storable propellant stages strap-on motors with 40 tons of liquid propellant in each.
The second is also an earth-storable liquid propellant stage loaded with 40-ton propellant.
The third stage is a cryogenic stage with a 15-ton propellant loading of liquid oxygen (LOX) and liquid hydrogen (LH2).
Incidentally this will be the first mission for the GSLV rocket to the Sun Synchronous Polar Orbit. The rocket was basically developed for orbiting communication satellites in the Geo Transfer Orbit (GTO).
GSLV-F16 is the 18th flight of India's GSLV series and the 12th flight with the indigenous cryogenic stage. This is the 9th operational flight of GSLV with indigenous Cryogenic stage.
The Payload Fairing or the heat shield in GSLV-F16/NISAR Mission is 4 m dia Ogive configuration.
NISAR-only for earth observation: A retired chief of ISRO said NISAR is only for earth observation and not for strategic purposes though it has SAR that can look through the clouds.
The Indian space agency said NISAR is a unique earth observation satellite and the first satellite to observe the earth with a dual frequency Synthetic Aperture Radar (NASA's L-band and ISRO's S-band).
The satellite will observe earth with a swath of 242 km and high spatial resolution, using SweepSAR technology for the first time.
According to ISRO, the satellite will scan the entire globe and provide all-weather, day-and-night data at 12-day intervals and enable a wide range of applications.
NISAR can detect even small changes in the Earth's surface such as ground deformation, ice sheet movement and vegetation dynamics.
Further applications include sea ice classification, ship detection, shoreline monitoring, storm characterization, changes in soil moisture, mapping and monitoring of surface water resources and disaster response, the Indian space agency added.
The data gathered will assist in tasks as infrastructure monitoring, disaster response, biomass assessment, and agricultural management.
ISRO identified science and applications that were complementary to the primary mission objectives: agricultural monitoring and characterization, landslide studies, Himalayan glacier studies, soil moisture, coastal processes, coastal winds, and monitoring hazards.
The NISAR launch is the result of strong technical cooperation between ISRO & NASA/JPL (National Aeronautics and Space Administration and Jet Propulsion Laboratory) technical teams for more than a decade.
NISAR will be the first Earth-observing satellite with two kinds of radar — an L-band system with a 10-inch (25-centimeter) wavelength and an S-band system with a 4-inch (10-centimeter) wavelength.
The NISAR carries a 12m wide deployable mesh reflector mounted onto a deployable 9m boom developed by NASA's JPL which shall be used by both-JPL-NASA developed L-Band SAR payload system and ISRO developed S-Band SAR payload.
Whether microwaves reflect or penetrate an object depends on their wavelength. Shorter wavelengths are more sensitive to smaller objects such as leaves and rough surfaces, whereas longer wavelengths are more reactive with larger structures like boulders and tree trunks.
So NISAR's two radar signals will react differently to some features on Earth's surface. By taking advantage of what each signal is or isn't sensitive to, researchers can study a broader range of features than they could with either radar on its own, observing the same features with different wavelengths.
After the successful in-orbit checkout of the satellite, the science operations phase will start and extend for three years and contain all data collection required to achieve the L1 science objectives.
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 activities will take place throughout the first five months, with yearly updates of 1-month duration.
The data acquired through S-band and L-band SAR from a single platform will help the scientists to understand the changes happening to Planet Earth.
A delayed launch: The NISAR satellite launch was to have happened much ahead but owing to several reasons it got delayed.
The Indian space agency had earlier said the NISAR satellite will be launched in 2022 or early 2023.
In 2025, the NISAR launch was expected to happen in June, but got delayed again.
It was on September 30, 2014, ISRO and NASA signed an equal partnership to collaborate and launch NISAR.
UNI VJ PRS