Satellite mission will closely monitor changes on Earth's surface

From the shifting sands of the Saharan desert to the cracking glaciers in the chilly Antarctic, our Earth is constantly transforming right beneath our feet. The upcoming U.S.-India NISAR (NASA-ISRO Synthetic Aperture Radar) mission is about to take us a step closer to understanding this ceaseless change and the intricate mechanisms behind it.

This remarkable satellite mission, set to launch in a few months, will track dynamic changes in Earth’s surface, from wetlands to ice sheets and disaster-hit infrastructure.

NISAR: Revolutionizing Earth observation

NISAR is a remarkable advancement in Earth observation, thanks to its unique dual-band radar system. This system combines two types of radar: the L-band, with a 25-centimeter wavelength, and the S-band, with a 10-centimeter wavelength.

The L-band can penetrate through vegetation and observe larger features such as tree trunks, boulders, or the ground beneath forest canopies. In contrast, the S-band, with its shorter wavelength, is more sensitive to smaller surface-level features like leaves and fine textures.

The complementary nature of these two radar signals enables scientists to study a wide range of Earth’s features with greater precision.

The L-band provides insights into broader and deeper structures, while the S-band focuses on finer surface details. Together, they offer a comprehensive view of Earth’s surface changes, capturing data on an unprecedented scale and frequency.

“The planet’s surfaces never stop changing – in some ways small and subtle, and in other ways monumental and sudden,” said Paul Rosen, NISAR Project Scientist at NASA’s Jet Propulsion Laboratory (JPL).

“With NISAR, we’ll measure that change roughly every week, with each pixel capturing an area about half the size of a tennis court.”

What NISAR can do

The NISAR satellite is designed to observe nearly all of Earth’s land and ice surfaces with exceptional precision. This means it can monitor changes across vast areas of the planet, including natural features like glaciers and forests.

The satellite will track how glaciers move and whether they are melting or growing. It will also monitor forests to measure growth or loss, helping us understand how much carbon they absorb or release. Additionally, it will observe wetlands to track changes in these vital ecosystems.

Beyond natural processes, NISAR will focus on major events like earthquakes, landslides, and volcanic eruptions. By detecting how the ground shifts during these events, it can provide critical information for disaster response teams.

For instance, it can help assess damage and guide recovery efforts. This data will also contribute to a better understanding of the global carbon cycle – how carbon moves through the atmosphere, land, and oceans – which is essential for studying climate change.

Legacy of an early radar satellite

NISAR is built on decades of radar technology advancements. Rosen noted that the concept of using spaceborne synthetic aperture radar (SAR) began in the 1970s with NASA’s Seasat mission.

Seasat was an early radar satellite. It was the first Earth-orbiting satellite designed for remote sensing of the ocean. While Seasat operated for just a few months, it revolutionized how scientists study Earth.

The satellite inspired later missions that refined radar imaging and laid the groundwork for today’s sophisticated systems, like NISAR.

This legacy demonstrates how earlier missions influenced modern Earth observation and continue to inspire scientists to innovate.

Significance of the NISAR mission

The NISAR mission will generate massive datasets to benefit scientists and decision-makers alike. Whether monitoring soil moisture or studying cryospheric processes, the data will be freely accessible via cloud storage.

“Our data products will fit the needs of users across the mission’s science focus areas,” noted Rosen.

The NISAR mission highlights the power of international collaboration. NASA and ISRO began working together in 2014 to combine their strengths and expertise.

Each agency contributed unique radar systems – NASA’s L-band radar and ISRO’s S-band radar – and together, they created a unified satellite mission to observe Earth.

This partnership wasn’t without challenges. With a 9,000-mile (14,500-kilometer) distance between them and operations across several time zones, coordination was complex.

Teams on different continents built parts of the satellite, which were later brought together in India for final assembly. Despite the logistical hurdles, the collaboration succeeded, demonstrating the commitment and innovation of both agencies.

Addressing global challenges

More than just advanced technology, NISAR symbolizes what can be achieved when nations work together.

This mission reflects a shared dedication to understanding Earth’s changes and addressing global challenges like climate change and disaster management.

As launch day approaches, NISAR stands as both a technological achievement and a beacon of international unity, ready to reveal valuable insights about our ever-changing planet.

Image Credit: NASA/JPL-Caltech

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