NISAR Joint Radar Antenna Deployment Phase Operations

The NASA-ISRO Synthetic Aperture Radar (NISAR) mission is an Earth Observatory operating in a near-polar orbit with primary mission objectives to measure changes in Earth’s surfaces and biomass every 12 days using both L-band and S-band radar systems. NISAR is a collaboration between NASA’s Jet Propulsion Laboratory (JPL) and multiple Indian Space Research Organisation (ISRO) centres. The Spacecraft bus and S-band radar are provided by ISRO, while the Radar Payload, consisting of the L-band radar and deployable Radar Antenna are provided by JPL. The Radar Antenna, which is the primary radar aperture for the mission, consists of a 12 meter diameter Radar Antenna Reflector (RAR) mounted to a 9 meter Radar Antenna Boom (RAB), which are both stowed to fit within ISRO’s launch vehicle, a Launch Vehicle Mark II (LVM-II). Deployment of the RAB and RAR from their stowed configuration to a fully deployed science configuration occurs within the designated Deployment Phase of the mission, which begins on mission day 10, after early Commissioning Phase activities are completed post launch, and extends nominally until mission day 17. The Deployment Phase requires close collaboration between ISRO and JPL teams to define the nominal plan for flight operations as well as potential off-nominal scenarios and recovery options, while adhering to several design and operational constraints. To ensure clear communication between organizations, detailed timelines were developed for each deployment day to capture the setup and execution of each daily activity down to the minute. The timelines provide a complete view of ground station coverage, uplink and downlink needs, hardware and software configurations, as well as critical deployment details. Time-ordered lists are generated from the timelines, which are used to develop procedures for on-orbit operations. In the final year leading up to launch and commissioning, planned for early 2024, the ISRO and JPL teams are working closely to plan scenario and operations tests to validate the joint commanding required in flight, and to ensure that on-orbit procedures and operations are fully rehearsed. Final flight tests are conducted as the NISAR Observatory is assembled and tested prior to launch.