The NISAR satellite, a joint project between NASA and ISRO, has successfully completed a 21-day thermal vacuum test, according to a statement from NASA. The test, conducted at ISRO’s Satellite Integration and Test Establishment in Bengaluru, evaluated the satellite’s ability to function in extreme temperatures and the vacuum of space. Scheduled for launch in early 2024, NISAR will scan the planet’s land and ice every 12 days, monitoring surface movements with high precision. It will observe earthquakes, landslides, volcanic activity, as well as track changes in forests, wetlands, and agricultural lands.
During the thermal vacuum test, engineers simulated the temperature swings the spacecraft will experience in orbit. The satellite was subjected to an 80-hour “cold soak” at -10 degrees Celsius, followed by an equally lengthy “hot soak” at up to 50 degrees Celsius. This rigorous testing ensured that the satellite’s thermal systems and its primary science instrument systems, the L-band and S-band radars, could withstand extreme temperature conditions in space.
Prior to the thermal vacuum test, engineers performed 20 days of testing in September to evaluate the radio signals from the radar systems’ antennas. The signals passed requirements in ISRO’s compact antenna test facility, thanks to the use of blue foam spikes that prevent radio waves from interfering with measurements.
With the successful completion of the thermal vacuum and compact antenna tests, NISAR will now undergo additional testing before being prepared for launch. It will be fitted with solar panels and a 40-foot radar antenna reflector, which will unfold in space at the end of a 30-foot boom. The satellite will eventually be transported to Satish Dhawan Space Centre for mounting on ISRO’s Geosynchronous Satellite Launch Vehicle Mark II and placed in low Earth orbit.
NISAR is the first space hardware collaboration between NASA and ISRO for an Earth-observing mission. The project is an equal collaboration, with NASA providing various components such as the L-band SAR, radar reflector antenna, and communication subsystem. ISRO is responsible for the spacecraft bus, launch vehicle, and the S-band SAR electronics.