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NISAR’s Odyssey: Pioneering Earth-Observing Satellite Clears Crucial Test

After it launches in early 2024, NISAR will scan nearly all of the planet’s land and ice twice every 12 days. In orbit, the satellite will extend its solar panels and nearly 40-foot (12-meter) radar antenna reflector, which resembles a snare drum and will unfold at the end of a 30-foot (9-meter) boom extending from the spacecraft. Credit: NASA-JPL/Caltech

During three weeks in a thermal vacuum chamber in Bengaluru, India, the joint NASAEstablished in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. Its vision is "To discover and expand knowledge for the benefit of humanity." Its core values are "safety, integrity, teamwork, excellence, and inclusion." NASA conducts research, develops technology and launches missions to explore and study Earth, the solar system, and the universe beyond. It also works to advance the state of knowledge in a wide range of scientific fields, including Earth and space science, planetary science, astrophysics, and heliophysics, and it collaborates with private companies and international partners to achieve its goals.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>NASA-ISRO satellite demonstrated its hardiness in a harsh, space-like environment.

NISAR, the trailblazing Earth-observing radar satellite being developed by the United States and Indian space agencies, passed a major milestone on November 13, emerging from a 21-day test aimed at evaluating its ability to function in the extreme temperatures and the vacuum of space.

NISAR’s Mission and Capabilities

Short for NASA-ISRO Synthetic Aperture Radar, NISAR is the first space hardware collaboration between NASA and the Indian Space Research Organisation, or ISRO, on an Earth-observing mission. Scheduled to launch in early 2024, the satellite will scan nearly all the planet’s land and ice twice every 12 days, monitoring the motion of those surfaces down to fractions of an inch. It will be able to observe movements from earthquakes, landslides, and volcanic activity and track dynamic changes in forests, wetlands, and agricultural lands.

NISAR Satellite Enters Thermal Vacuum Chamber

The NISAR satellite entered the thermal vacuum chamber at an ISRO facility in Bengaluru on October 19. It emerged three weeks later having met all requirements of its performance under extreme temperatures and space-like vacuum. Credit: ISRO

Rigorous Testing Procedures

The thermal vacuum test occurred at ISRO’s Satellite Integration and Test Establishment in the southern Indian city of Bengaluru. It’s one of a battery of tests the satellite will face leading to launch. Other tests will ensure it can withstand the shaking, vibration, and jostling that it will encounter during launch.

NISAR, partially covered in gold-hued thermal blanketing, entered the vacuum chamber on October 19. Over the following week, engineers and technicians lowered the pressure to an infinitesimal fraction of the normal pressure at sea level. They also subjected the satellite to an 80-hour “cold soak” at 14 degrees FahrenheitThe Fahrenheit scale is a temperature scale, named after the German physicist Daniel Gabriel Fahrenheit and based on one he proposed in 1724. In the Fahrenheit temperature scale, the freezing point of water freezes is 32 °F and water boils at 212 °F, a 180 °F separation, as defined at sea level and standard atmospheric pressure. ” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Fahrenheit (minus 10 degrees CelsiusThe Celsius scale, also known as the centigrade scale, is a temperature scale named after the Swedish astronomer Anders Celsius. In the Celsius scale, 0 °C is the freezing point of water and 100 °C is the boiling point of water at 1 atm pressure.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Celsius), followed by an equally lengthy “hot soak” at up to 122 F (50 C). This simulates the temperature swings the spacecraft will experience as it is exposed to sunlight and darkness in orbit.

NISAR Satellite ISRO Antenna Testing Facility

The NISAR satellite stayed in this ISRO antenna testing facility for 20 days in September as engineers evaluated the performance of its L- and S-band radar antennas. The foam spikes lining the walls, floor, and ceiling prevent radio waves from bouncing around the room and interfering with measurement. Credit: ISRO

Collaborative Efforts and Future Plans

ISRO and JPLThe Jet Propulsion Laboratory (JPL) is a federally funded research and development center that was established in 1936. It is owned by NASA and managed by the California Institute of Technology (Caltech). The laboratory's primary function is the construction and operation of planetary robotic spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA's Deep Space Network. JPL implements programs in planetary exploration, Earth science, space-based astronomy and technology development, while applying its capabilities to technical and scientific problems of national significance.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>JPL teams worked around the clock during the three-week period, testing the performance of the satellite’s thermal systems and its two primary science instrument systems – the L-band and S-band radars – under the most extreme temperature conditions they will experience in space.

This latest round of testing followed 20 days of testing in September in which engineers used ISRO’s compact antenna test facility to evaluate whether the radio signals from the two radar systems’ antennas passed requirements. Blue foam spikes lining the facility’s walls, floor, and ceiling prevent radio waves from bouncing around the room and interfering with measurement.

With thermal vacuum and compact antenna tests successfully done, NISAR will soon be fitted with its solar panels and its nearly 40-foot (12-meter) radar antenna reflector, which resembles a snare drum and will unfold in space at the end of a 30-foot (9-meter) boom extending from the spacecraft.

The satellite will undergo additional tests before being packed up and transported about 220 miles (350 kilometers) eastward to Satish Dhawan Space Centre, where it will be mounted atop ISRO’s Geosynchronous Satellite Launch Vehicle Mark II rocket and sent into low Earth orbit.

More About the Mission

NISAR is an equal collaboration between NASA and ISRO and marks the first time the two agencies have cooperated on hardware development for an Earth-observing mission. NASA’s Jet Propulsion Laboratory, which is managed for the agency by Caltech in Pasadena, California, leads the U.S. component of the project and is providing the mission’s L-band SAR. NASA is also providing the radar reflector antenna, the deployable boom, a high-rate communication subsystem for science data, GPSGPS, or Global Positioning System, is a satellite-based navigation system that provides location and time information anywhere on or near the Earth's surface. It consists of a network of satellites, ground control stations, and GPS receivers, which are found in a variety of devices such as smartphones, cars, and aircraft. GPS is used for a wide range of applications including navigation, mapping, tracking, and timing, and has an accuracy of about 3 meters (10 feet) in most conditions.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>GPS receivers, a solid-state recorder, and payload data subsystem. U R Rao Satellite Centre (URSC) in Bengaluru, which leads the ISRO component of the mission, is providing the spacecraft bus, the launch vehicle, and associated launch services and satellite mission operations. ISRO’s Space Applications Centre in Ahmedabad is providing the S-band SAR electronics.

Source: SciTechDaily