NASA uses moonlight to improve Earth observation accuracy

NASA Turns to the Moon for Sharper Views of Earth

In a high-flying experiment with deep implications for Earth science, NASA’s air-LUSI mission has captured the most precise measurements of moonlight ever recorded, offering a transformative new way to calibrate Earth-observing satellites.

In March 2025, the ER-2 science aircraft, NASA’s highest-flying airborne research platform, conducted a series of night flights from Armstrong Flight Research Center in California. The goal: to observe the Moon at multiple phases using the Airborne Lunar Spectral Irradiance (air-LUSI) instrument, which tracks the light reflected by the Moon across different wavelengths.

Why Moonlight Matters for Earth Science

The Moon, reflecting the Sun’s light without its own atmosphere or weather systems, acts as an ideal stable reference point for calibrating sensors aboard satellites. These calibrations improve the accuracy of critical data about Earth—such as weather patterns, vegetation health, and ocean dynamics.

“The Moon becomes the perfect benchmark for satellites to consistently and accurately measure processes on Earth,” said Kevin Turpie, air-LUSI principal investigator at NASA’s Goddard Space Flight Center.

Air-LUSI’s unprecedented precision reduces the need for costly onboard reference tools on satellites and helps cut development costs, while enhancing data quality.

Reaching for Precision at 70,000 Feet

Flying at stratospheric altitudes near 70,000 feet, above 95% of the atmosphere, the ER-2 aircraft provides a vantage point virtually free from atmospheric distortion. That clarity enabled scientists to capture highly accurate data with minimal interference from particles and gases that normally complicate measurements at lower altitudes.

“To date, air-LUSI measurements of the Moon are the most accurate ever made,” said Kelsey Bisson, NASA program scientist for the mission.

A Transnational Effort in Innovation

The mission is the product of a collaborative effort between NASA, the National Institute of Standards and Technology (NIST), the U.S. Geological Survey, University of Maryland Baltimore County, and McMaster University in Ontario, Canada.

Canadian researchers played a key role in the project, contributing a state-of-the-art HAAMR telescope mount, designed to autonomously track the Moon from the ER-2 aircraft. This robotic system, flown for the first time during the March mission, allowed engineers to collect data with exceptional consistency and precision.

“The collective effort of American and Canadian team members offers an opportunity for truly exciting engineering and science collaboration,” said Andrew Gadsden, co-investigator and mechanical engineering professor at McMaster University.

Future Benefits for Satellite Missions

The accuracy of the air-LUSI data stands to benefit a wide range of Earth-observing missions. Satellites calibrated using these lunar references can deliver sharper images, more reliable climate models, and better disaster monitoring.

“This is the highest-accuracy measurement of moonlight,” said Dr. John Woodward IV, NIST co-investigator. “Air-LUSI represents an important evolutionary step in Earth observation.”

In addition to its immediate impact, the mission also offers a blueprint for more affordable and efficient satellite design, thanks to the reduced need for internal calibration systems.

NASA’s air-LUSI project exemplifies how leveraging a natural constant—the Moon—can unlock new capabilities in monitoring our changing planet. As data from the mission are integrated into Earth-observing technologies, we move closer to a future where satellites can deliver environmental insights with unprecedented clarity.

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