NASA starshade would enable astronomers to directly image rocky exoworlds

A NASA-led team hopes to take a shortcut to direct imaging of extrasolar Earth-like planets. The idea is to use what they call a hybrid telescope composed of an orbital starshade coupled with the next-generation extremely large ground-based optical telescopes.

Positioned some 175,000 km (109,000 miles) away in an elliptical Earth orbit, the starshade would likely first be used in conjunction with the European Southern Observatory’s Extremely Large Telescope, now scheduled to see scientific first light in northern Chile by late 2030.

The starshade would block out the parent star’s light to enable direct optical observations of nearby solar systems and rocky Earth-sized worlds. These planetary systems would all be located within some 20 light-years of Earth (118 trillion miles).

Dubbed the Hybrid Observatory for Earth-like Exoplanets (HOEE), the team has already applied for Phase B NIAC (NASA Innovative Advanced Concepts) funding, which they hope will be granted by 2027.

Current space-based direct-imaging instruments, such as NASA’s James Webb Space Telescope’s Near Infrared Camera and NASA’s planned Roman Space Telescope’s Coronagraph Instrument, cannot directly observe Earth-like exoplanets, the authors of a 2026 paper in the journal Nature Astronomy write.

“We need to go for something that is more efficient and available now: a hybrid observatory that can observe the exoplanetary system in optical light,” Vladimir Airapetian, a senior astrophysicist at NASA Goddard Space Flight Center and a HOEE project team member, told me in Paris.

The challenge is to block light from the star to reveal a planet that, in optical light, would be a billion times fainter than the star itself. To do that, the starshade would create an artificial eclipse to occult the parent star’s light, allowing ground-based observers to receive reflected light directly from the extrasolar planet.

Dubbed an occulter, the starshade would likely feature 48 petals, each 24.5 meters (80 feet) long, and a 50-meter (164-foot)-diameter central disk, the Nature Astronomy paper’s authors note. The starshade would also be capable of being repositioned within 6 meters (20 feet) of accuracy, using some sort of microthrusters, most likely powered by hot hydrogen gas.

“Our team proves that by deploying a starshade to cast a ‘perfect shadow’ over Earth’s largest telescopes, HOEE can suppress stellar glare before it ever enters the atmosphere,” Airapetian says.

The starshade would hover directly on the line of sight between the ground telescope and the target star, offering continuous fine alignment on the celestial target, Mather wrote in a previous presentation. The concept relies on a long elliptical astro-stationary orbit to match Earth’s rotation, using chemical propulsion for station-keeping and solar electric propulsion for retargeting, Mather noted.

HOEE’s much sharper images would also allow astronomers to see entire exoplanetary systems and clearly separate planet images from other Earth-sized planets and the host star itself. This hybrid telescope’s extreme sensitivity would, in principle, enable the detection of an exoearth within the first minute of observation.

HOEE would also enable a definitive path to identifying the chemical signatures of life.

Airapetian wants to find active stars that flare frequently enough to create extrasolar auroras on rocky planets orbiting solar-type F, G and K stars. These would ideally be stars in their first billion years on the hydrogen-burning main sequence. The idea is to look for potential exoearths circling other sun-like stars that might have either precursors of life or primitive life.

“We’re going for the spectral lines from red and green auroras that would signal that the atmospheres of these planets can support nitrogen and oxygen,” Airapetian says.

As for projected costs and the final design?

Airapetian says it would come in at around the billion-dollar range. The final occulter design would likely involve an inflatable structure to keep the total launch mass under 1,500 kg. The idea is that the starshade would efficiently collapse into a standard launch vehicle’s payload, Mather wrote.

The bottom line?

For decades, the starshade was a beautiful but “impossible” dream, Airapetian says. Today, through NASA funding, that dream is becoming a buildable reality, he says.

Who’s behind this story?

Swati Mestri

Swati Mestri holds a bachelor’s degree in Electronics Engineering and has worked as a content editor since 2019. She has experience editing research documents across technology, health care, and materials science, and has a particular interest in technology and space.

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Andrew Zinin

Master’s in physics with research experience. Long-time science news enthusiast. Plays key role in Science X’s editorial success.

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