Radar Antenna Reflector on NISAR Mission in Full ‘Bloom’

By

 Seventeen days after NISAR’s launch from southeastern India, an essential piece of science hardware has unfurled in orbit.

Spanning 39 feet (12 meters), the drum-shaped antenna reflector on the NISAR (NASA-ISRO Synthetic Aperture Radar) satellite mission from NASA and the Indian Space Research Organisation (ISRO) successfully unfurled in low Earth orbit. The reflector had been stowed, umbrella-like, until the 30-foot (9-meter) boom that supports it could be deployed and locked in place.

Launched by ISRO on July 30 from the Satish Dhawan Space Centre on India’s southeastern coast, NISAR will track the motion of ice sheets and glaciers, the deformation of land due to earthquakes, volcanoes, and landslides, and changes in forest and wetland ecosystems down to fractions of an inch. It also will aid decision-makers in fields as diverse as disaster response, infrastructure monitoring, and agriculture.

The mission carries the most sophisticated radar systems ever launched as part of a NASA mission. In a first, the satellite combines two synthetic aperture radar (SAR) systems: an L-band system that can see through clouds and forest canopy, and an S-band system that can see through clouds as well but is more sensitive to light vegetation and moisture in snow. The reflector plays a key role for both systems, which is why the successful deployment of the hardware is such a significant milestone.

How Bloom Works

Weighing about 142 pounds (64 kilograms), the reflector features a cylindrical frame made of 123 composite struts and a gold-plated wire mesh. On Aug. 9, the satellite’s boom, which had been tucked close to its main body, started unfolding one joint at a time until it was fully extended about four days later. The reflector assembly is mounted at the end of the boom.

Then, on Aug. 15, small explosive bolts that held the reflector assembly in place were fired, enabling the antenna to begin a process called the “bloom” — its unfurling by the release of tension stored in its flexible frame while stowed like an umbrella. Subsequent activation of motors and cables then pulled the antenna into its final, locked position.

To image Earth’s surface down to pixels about 30 feet (10 meters) across, the reflector was designed with a diameter about as wide as a school bus is long. Using SAR processing, NISAR’s reflector simulates a traditional radar antenna that for the mission’s L-band instrument would have to be 12 miles (19 kilometers) long to achieve the same resolution.

The NISAR satellite is the culmination of decades of space-based radar development at JPL. Starting in the in the 1970s, JPL managed the first Earth-observing SAR satellite, Seasat, which launched in 1978, as well as Magellan, which used SAR to map the cloud-shrouded surface of Venus in the 1990s.

<<< About NISAR Mission

NASA News

Comments

Post a Comment

Popular posts from this blog

Russian parliament passed a bill to revoke its ratification of the Comprehensive Test Ban Treaty

By
Relevance:  Russia revokes ratification of nuclear test ban treaty (CTBT) - ICAN But it affirmed that it will  retain its cooperation with the treaty’s verification system and implementing organisation.  Comprehensive Test Ban Treaty: The Comprehensive Test Ban Treaty (CTBT), which opened for signature in 1996, was intended to prohibit all nuclear weapon test explosions. Over 2,000 nuclear tests occurred between 1945 and 1996: the United States (1,000+), the Soviet Union (700+), France (200+), the United Kingdom and China (45 each). As at January 2013, 183 countries had signed the Treaty, of which 158 have also ratified it, including three of the nuclear weapon states (France, the Russian Federation and the United Kingdom). However, 44 specific nuclear technology holder countries must sign and ratify before the CTBT can enter into force. Of these, eight are still missing: China, Egypt, India , Iran, Israel, North Korea, Pakistan and the US. India , North Korea and Pakista...
Read more

ISRO developing semi-cryogenic engine working on LOX Kerosene propellant

By
ISRO is developing a 2000 kN thrust semi-cryogenic engine working on an LOX Kerosene propellant combination for enhancing the payload capability of LVM3 and for future launch vehicles. Liquid Propulsion Systems Centre (LPSC) is the lead centre for the development of semi-cryogenic propulsion systems with the support of other launch vehicle centres of ISRO. The assembly and testing of the propulsion modules were done at the ISRO propulsion complex (IPRC), Mahendragiri. As part of the engine development, a pre-burner ignition test article, which is a full complement of the engine power head system excluding the turbopumps is realized. The first ignition trial was conducted successfully on May 2, 2024, at semi cryo integrated engine test facility (SIET) at IPRC, Mahendragiri, which was dedicated to the nation recently by the honorable Prime Minister of India. Smooth and sustained ignition of the preburner is demonstrated which is vital for the starting of the semi-cryogenic engine. Semi-c...
Read more

Interstellar space and Interstellar Probes ( Voyager and New Horizons Missions )

By
Interstellar Space: Interstellar space is often called the space between the stars, but more specifically, it’s the region between our Sun’s heliosphere and the astrospheres of other stars. Our heliosphere is a vast bubble of plasma – a gas of charged particles – that spews out of the Sun. This outflow is known as the solar wind. The bubble surrounds the Sun and stretches beyond the planets. Both Voyager spacecraft had to travel more than 11 billion miles (17 billion kilometers) from the Sun in order to cross the edge of the heliosphere. This bubble is moving through interstellar space as the Sun orbits the center of the Milky Way galaxy. As our heliosphere plows through space, it creates a bow wave, like the wave formed by the bow of a ship. Kuiper Belt &  Oort Cloud: The Kuiper Belt is a doughnut-shaped ring of icy objects around the Sun, extending just beyond the orbit of Neptune from about 30 to 55 AU. Similar to the asteroid belt, the Kuiper Belt is a region of leftovers f...
Read more