NASA's 42-Year Quest to Understand Earth's Energy Balance

Since 1984, NASA scientists have been watching Earth breathe, measuring every ray of sunshine our planet catches and every bit of heat it releases back into space.

It started with a pre-dawn launch that lit up the Florida sky twice. When the space shuttle Challenger carried NASA's Earth Radiation Budget Satellite into orbit in October 1984, retired experiment scientist Bruce Barkstrom watched the exhaust brighten the overcast morning from below, then again as sunlight reflected off the plume above the clouds. "It's impossible for me to describe this without getting a little emotional," he recalled.

The mission was elegant in its simplicity: measure Earth's energy budget. Just like balancing a checkbook, scientists needed to know how much solar energy comes in versus how much heat goes out. That delicate equilibrium controls everything from daily weather to long-term climate patterns.

But getting there took painstaking work. The first science team meeting involved an entire day of debate just to define where the top of the atmosphere sits. They settled on 18 miles above Earth's surface, the level of precision needed to get the measurements right.

For ten years, the satellite delivered invaluable data. In the late 1980s, these instruments provided the first direct proof that clouds cool Earth's climate, a discovery that reshaped our understanding of the planet's systems.

The work didn't stop there. In 1997, NASA launched the first Clouds and the Earth's Radiant Energy System (CERES) instrument, building on those early measurements. Six more CERES instruments followed, each one more accurate than the last. Principal Investigator Kory Priestley calls them "probably the most accurate radiometry that NASA has flown."

Today, NASA Langley's Earth Radiation Budget Science Team remains the only group producing this crucial data globally. The measurements inform weather forecasts, help industries plan for seasonal changes, and guide policy makers in protecting our future.

The Ripple Effect

The continuous data record stretching back to 1978 has transformed how we understand and predict Earth's behavior. Farmers can better plan planting seasons. Cities can prepare for extreme weather. Industries can adapt to changing conditions with confidence instead of guesswork.

This decades-long commitment to measurement has given us something priceless: certainty in an uncertain world. The data doesn't just sit in scientific journals. It flows into the weather apps on our phones, the forecasts that help us plan our days, and the long-term models that help communities prepare for tomorrow.

The work continues. NASA's Total and Spectral Solar Irradiance Sensor currently measures the Sun's energy from the International Space Station, and scientists are already designing the next generation of instruments.

"With Earth observations, you never complete your understanding," Barkstrom said, and that's actually the good news. Every measurement brings new insights, and every insight helps us take better care of the only home we have.