A New Tool for Planet Hunters
Pandora is a small satellite, or 'SmallSat', launched as part of NASA's cost-effective Pioneers program, which focuses on fast-paced, targeted science missions. Launched in January 2026, its primary job is to study the atmospheres of at least 20 known
exoplanets—planets orbiting stars other than our Sun. To do this, it uses a technique called transit spectroscopy. When an exoplanet passes in front of its star from our perspective, a tiny fraction of the starlight filters through the planet's atmosphere. By analyzing this light, scientists can detect the chemical fingerprints of elements and molecules, searching for clues about the presence of water, clouds, or hazes.
Solving the 'Star Spot' Problem
Studying exoplanet atmospheres isn't as simple as just looking at starlight. The host stars themselves are active and variable. They have features like starspots—cooler, darker areas similar to our Sun's sunspots—and plages, which are brighter, hotter regions. As a star rotates, these features can change the light it emits, creating false signals that can either mimic the signature of an atmospheric molecule or hide it completely. This issue, known as 'stellar contamination,' has been a significant roadblock for astronomers, making it difficult to be certain about the atmospheric composition of distant worlds. Pandora was specifically designed to tackle this problem head-on.
How Pandora Sees Clearly
Pandora's clever solution is to observe planets and their stars simultaneously in two different kinds of light. Its 45-centimeter telescope is equipped with a beam-splitter that directs visible light to one instrument and near-infrared light to another. This dual approach is key because the confusing signals from starspots are more prominent in visible light. By collecting long-duration observations—staring at each target system for 24 hours at a time—Pandora can track the star's variability in the visible spectrum. This allows scientists to create a model of the star's activity and subtract it from the infrared data, leaving behind a much cleaner and more reliable signal from the exoplanet's atmosphere.
A Small Satellite with a Big Role
While NASA has powerful observatories like the James Webb Space Telescope (JWST), Pandora fills a unique and complementary niche. Flagship missions like Webb are in high demand and can't dedicate the long, continuous observation time needed to monitor a star's full rotation. Pandora, as a smaller, dedicated mission, can perform these long stares, gathering the data necessary to clean up observations. In fact, its near-infrared detector is a spare part originally built for JWST. The data from Pandora will lay the groundwork for future studies, helping astronomers better interpret findings from Webb and more effectively search for planets that might have conditions suitable for life.
What Comes Next for Pandora
Now that its checkout and commissioning phase is complete, Pandora has begun its one-year primary science mission. It will systematically work through its list of at least 20 target exoplanets, ranging in size from rocky Earth-sized worlds to gas giants, orbiting relatively cool K and M dwarf stars. For each target, the mission will gather data over about 10 separate transits to build a robust understanding of the system. The results will not only reveal more about the specific atmospheres of these planets but will also provide a vital toolkit for astronomers worldwide, refining the methods used in the ongoing quest to find another Earth.
