CHENNAI, Apr 14: US Space Agency NASA and the Indian Space Research Organisation (ISRO) are reviewing potential dates for the launch of INDO-US joint NISAR Satellite Mission.
The satellite, to be placed in a Low Earth Orbit, has been tested at ISRO facility in Bengaluru and will be transported to the spaceport of Sriharikota, about 110 km from here.
The launch is likely either in May or June depending upon the launch window availability after undergoing further tests of satellite at the SHAR Range.
In an update, NASA in its website said Work on the NISAR satellite has been completed at the ISRO Satellite Integration and Testing Establishment in Bengaluru, and preparations are underway to transport it to the launch site at the agency’s Satish Dhawan Space Centre in Sriharikota on India’s southeastern coast.
NASA and ISRO now are reviewing potential launch dates for the NISAR (NASA-ISRO Synthetic Aperture Radar) mission.
Launch services are provided by ISRO, using the Geosynchronous Launch Vehicle Mark-II rocket that will carry the spacecraft into a Low Earth Orbit.
The launch readiness date for the mission will be determined by the two agencies in the coming weeks, NASA said. .
In fact, the Satellite was already shifted to Sriharikota from Bengaluru for the launch but has been taken back due to some technical glitch in reflector antenna, which is a crucial part of NISAR’s radar system. .
“The NISAR satellite, a joint venture between NASA and ISRO, was indeed taken back from Sriharikota for further testing, specifically for the reflector antenna, which is a crucial component of the NISAR’s radar system”.
It experienced an issue that required a thermal coating to be applied, leading to its return to the US for rectification.
This delay has pushed the launch date of NISAR to later in the year. The issue pertained to the NISAR satellite is the reflector antenna, which is 12 meters in diameter, was found to have a potential overheating problem during flight.
“To address this, the reflector antenna was returned to the US for a special thermal coating
to prevent overheating. After the coating was applied, the antenna was returned to India for
reintegration with the NISAR satellite and further testing”, NASA said.
NISAR is designed to provide global measurements of Earth’s surface changes, including
land deformation, glacier movement, and forest degradation, using advanced radar imaging.
The planned mission life is three years.
The NISAR satellite will scan nearly all of Earth’s land and ice surfaces twice every 12 days
to measure changes in the planet’s ecosystems, growth and retreat of its land and sea ice,
and deformation of its crust.
The information provided by NISAR will help with such tasks as infrastructure monitoring,
disaster response, biomass assessment, and agricultural management.
Meanwhile, the Indian Space Agency said NASA-ISRO SAR (NISAR) is a Low Earth Orbit
observatory being jointly developed by NASA and ISRO and it will map the entire globe in
12 days and provide spatially and temporally consistent data for understanding changes
in Earth’s ecosystems, ice mass, vegetation biomass, sea level rise, ground water and
natural hazards including earthquakes, tsunamis, volcanoes and landslides.
NISAR carries L and S dual band Synthetic Aperture Radar (SAR), which operates with
Sweep SAR technique to achieve large swath with high resolution data. The SAR payloads
mounted on Integrated Radar Instrument Structure (IRIS) and the spacecraft bus are together
called an observatory.
The Jet Propulsion Laboratories and ISRO are realizing the observatory which shall
not only meet the respective national needs but also will feed the science community
with data encouraging studies related to surface deformation measurements through
repeat-pass InSAR technique.
This flagship partnership would have major contributions from both agencies.
NASA is responsible for providing the L-Band SAR payload system in which the ISRO
supplied S-Band SAR payload and both these SAR systems will make use of a large
size (about 12m diameter) common unfurl able reflector antenna .
In addition, NASA would provide engineering payloads for the mission, including a
Payload Data Subsystem, High-rate Science Downlink System, GPS receivers and
a Solid State Recorder.
“The NISAR Observatory will be launched from SDSC SHAR, Sriharikota on the “,
southeast coast of the Indian peninsula, on the GSLV expendable launch vehicle.
The target launch readiness date earlier fixed for March 2025 has got delayed due
to some technical glitches following which the satellite was subjectedn to more tests
and checks before being readied for transporting it to Sriharikota. .
The launch sequence encompasses the time interval that takes the observatory from
the ground, encapsulated in the launch vehicle fairing, to after separation, and ends
with the completion of solar array deployment and the observatory in an Earth-pointed
attitude and in two-way communication with the ground.
Stating that the launch sequence is a critical event, ISRO on the commissioning phase
said, the first 90 days after launch will be dedicated to commissioning, or in-orbit check
out (IOC), the objective of which is to prepare the observatory for science operations.
Commissioning is divided into sub-phases of initial checkout (ISRO engineering systems
and JPL engineering payload checkout), spacecraft checkout and instrument checkout.
Philosophically, the sub-phases are designed as a step-by-step build up in capability to
full observatory operations, beginning with the physical deployment of all deployable parts
(notably the boom and radar antenna, but not including the solar arrays which are deployed
during launch phase), checking out the engineering systems, turning on the radars and
testing them independently and then conducting joint tests with both radars operating.
Then the science operations phase begins at the end of commissioning and extends for
three years and contains 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 con icts with science observations.
Extensive calibration and validation (CalVal) activities will take place throughout the first
five months, with yearly updates of 1-month duration.
The observation plan for both L- and S-band instruments, along with engineering activities
(e.g., maneuvers, parameter updates, etc.), will be generated pre-launch via frequent
coordination between JPL and ISRO.
This plan is called the reference mission; the science observations alone within that reference
mission is called the reference observation plan (ROP), ISRO said.
The schedule of science observations will be driven by a variety of inputs, including L-and
S-band target maps, radar mode tables, and spacecraft and ground-station constraints
and capabilities.
This schedule will be determined by JPL’s mission planning team, and the project will
endeavour to y the reference mission, which includes these science observations
exactly as planned pre-launch (accommodating for small timing changes based on the
actual orbit). (UNI)
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