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Energy balance

Every day, the sun emits huge amounts of radiative energy. Earth intercepts a small amount of that energy nearly 93 million miles away. Roughly 30% of that radiation doesn’t stay on Earth but, rather, returns to space.

The amount of energy coming to Earth from the sun versus the energy that exits the planet into space makes up Earth’s energy budget. Even small changes in those numbers can have profound impacts for the ocean and weather systems that affect life on Earth, Pilewskie said.

To monitor that balance, Libera will adopt a polar orbit and will cover all latitudes of the planet. Its sensor head will swivel back and forth constantly, allowing the instrument to survey the entire planet every day.

Peter Pilewskie, principal investigator for Libera

Brian Boyle, program manager for Libera

Kate Barone, performance testing director for Libera

Pilewskie added that scientists can learn a lot by following Earth’s energy budget. Scientists have long known that an imbalance in energy exists between the �鶹ӰԺ equator and poles—with more energy building up at the equator.

Observations from the 1960s, however, revealed that the imbalance of radiative energy between the equator and poles was much greater than predicted. That imbalance is responsible for driving large-scale circulation patterns around the planet, including the jet streams, trade winds, and the Gulf Stream current in the Atlantic Ocean. Those circulation patterns regulate weather on Earth.

“Libera’s fundamental measurements of Earth’s energy flows improve our understanding of how the Earth system works and how it is changing, with practical benefits across a myriad of applications,” Pilewskie said. “There’s a lot of fulfillment in knowing that our important measurements can impact society.”

Shag carpet

The key to Libera lies in its innovative sensors, which have never flown into space on a mission of this size.

These sensors include countless incredibly small carbon “nanotubes” and are among the blackest materials ever invented. Scientists at the U.S. National Institute of Standards and Technology (NIST) developed the .

Kate Barone, the performance testing director for Libera at LASP compared the sensors to “a super shaggy piece of carpet made out of carbon.”

When radiation streaming from Earth encounters Libera, those black sensors will absorb the rays and heat up ever so slightly. The instrument records those small changes in temperature to calculate how much radiative energy is leaving the planet.

Barone graduated from CU �鶹ӰԺ with a bachelor’s degree in aerospace engineering sciences in 2023. She designed tests to make sure that Libera will work as promised, and her experiences gave her invaluable insights into just how complex spacecraft can be.

“It's given me an awesome opportunity to know some of the intricate details of how Libera works, down to its smallest components,” she said.

More than 100 people, including numerous early-career engineers like Barone, have worked on Libera over the years. They’ve solved a lot of tough problems, said Brian Boyle, program manager for the instrument.

Libera, for example, will scan across the Earth about 30 million times during its 5-year mission. Engineers on the project had to design a motor that could last that long in space without breaking down.

“The Libera team members have incredible passion for what they're doing,” said Brian Boyle, program manager for Libera at LASP. “They’ve invented this new world class instrument, and it works exactly as designed.”