NASA Starshade Could Enable Direct Imaging of Earth-Like Exoplanets

For decades, astronomers have faced an almost insurmountable problem: the stars we want to study are so blindingly bright that any planets orbiting them vanish in the glare. A rocky world the size of Earth, reflecting light from its parent star, would appear a billion times fainter than the star itself—like trying to spot a candle next to a searchlight. Now a NASA-led team believes they have found a way around this ancient obstacle, and their solution is elegantly simple: put a giant shade in space.

The concept, called the Hybrid Observatory for Earth-like Exoplanets, or HOEE, pairs an orbital starshade with the next generation of ground-based telescopes. The starshade would orbit Earth at a distance of roughly 175,000 kilometers—about halfway to the moon—positioned directly between a target star and a telescope on the ground. Its job would be to cast an artificial eclipse, blocking the star's overwhelming light and allowing astronomers to see the faint reflected glow of planets orbiting nearby stars. The team has already applied for Phase B funding from NASA's Innovative Advanced Concepts program, with hopes of securing support by 2027.

The starshade itself would be a remarkable piece of engineering. Roughly 50 meters across at its central disk, it would sprout 48 petals, each stretching 24.5 meters long, creating a flower-like silhouette in space. The entire structure would need to be collapsible—designed as an inflatable system that could fold into a standard rocket's payload bay, keeping the total launch mass under 1,500 kilograms. Once in orbit, the shade would maintain its position using microthrusters powered by hot hydrogen gas, capable of repositioning itself within six meters of perfect alignment. This precision matters enormously: the starshade must hover directly on the line of sight between the ground telescope and the target star, creating what Vladimir Airapetian, a senior astrophysicist at NASA Goddard Space Flight Center, calls a "perfect shadow."

The ground-based partner in this arrangement would be the European Southern Observatory's Extremely Large Telescope, scheduled to begin scientific observations in northern Chile by late 2030. This telescope, one of the most powerful optical instruments ever built, would receive the reflected light from distant planets that the starshade has revealed. Together, these two instruments—one in space, one on Earth—would form a hybrid system far more capable than either could be alone. The starshade would suppress stellar glare before it ever enters Earth's atmosphere, a crucial advantage over space-based telescopes that must contend with the full force of starlight.

What makes HOEE genuinely transformative is its reach and sensitivity. The system could observe rocky planets within about 20 light-years of Earth—a region containing some of the nearest stars in our cosmic neighborhood. More remarkably, the extreme sensitivity of the hybrid approach would theoretically allow astronomers to detect an Earth-like world within the first minute of observation. The sharp images would reveal entire planetary systems at once, allowing researchers to distinguish individual planets from one another and from their host star with unprecedented clarity.

But the real prize lies deeper. Airapetian is hunting for biosignatures—the chemical fingerprints of life itself. His team plans to search for auroras on distant rocky planets, the same shimmering light shows that dance across Earth's polar skies. These extraterrestrial auroras would reveal the presence of nitrogen and oxygen in a planet's atmosphere, elements that on Earth are strongly associated with biological processes. The team would focus on planets orbiting young, active stars similar to our sun, worlds that might harbor either the chemical precursors of life or primitive life itself.

The cost of realizing this dream would be substantial: roughly a billion dollars. Yet for Airapetian, this represents a remarkable shift. What was once dismissed as beautiful but impossible—a starshade in space working in concert with Earth's mightiest telescopes—is now becoming an engineering problem to solve rather than a physicist's fantasy. The path from concept to reality remains long, but the first steps are already underway.