This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: 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.
Extract — continue reading at the source.
