HELSINKI — China aims to construct an array of telescopes in deep space to search for habitable planets orbiting other stars.

The Miyin project envisions sending four light-collecting telescopes and a beam combiner to Sun-Earth Lagrange point 2. Flying in formation, the spacecraft will use interferometric techniques to provide high angular resolution mid-infrared observations to directly image and characterize exoplanets around stars up to 65 light-years away.

The main objective would be to detect potentially habitable terrestrial planets orbiting Sun-like stars in our neighborhood within the Milky Way.

The project is still in the development phase, but current plans map out on-orbit technology demonstrations in 2024, followed by interferometry experiments conducted aboard the Tiangong space station a year later. 

A prototype of the array would then launch around 2027, before building the five-spacecraft system at L2 in 2030. A further four spacecraft could be added to the array in a second mission phase beyond 2030.

An earlier published journal paper suggests the telescopes and central beam combiner will operate at distances of between 40 and 300 meters from each other. The array will be capable of a spatial resolution of 0.01 arcseconds for systems up to 20 parsecs away.

The concept was presented at an event related to China’s national space day celebrations in Hefei, Anhui province. The event has been held annually since 2016, and was for the anniversary of the launch of the country’s first satellite, Dongfanghong-1, on April 24, 1970.

If approved and deployed, the project would be of great scientific value, according to Sarah Casewell, research fellow and lecturer at the School of Physics and Astronomy at the University of Leicester. 

“The proposed spatial resolution of 0.01 arcseconds is comparable or better than NASA’s proposed Habitable Worlds Observatory, which is likely to have a six-meter-diameter mirror and a coronagraph to image exoplanets in the habitable zones of 100 stars within 25 parsecs,” Casewell told SpaceNews.

Systems comprising multiple space telescopes have been proposed previously, including NASA’s Terrestrial Planet Finder and ESA’s Darwin concepts. NASA is considering an $11 billion project named the Habitable Worlds Observatory which would launch in the 2040s and operate in the ultraviolet, visible and near infrared bands.

“This multi-spacecraft concept I think is unique within planned exoplanet missions right now, and will be complementary to JWST and Habitable Worlds, which has a similar spatial resolution but is likely to have a coronagraph or star shade for high contrast imaging.”

The Miyin mission would also be used to observe other targets such as protoplanetary disks and active galactic nuclei and a range of celestial bodies within our solar system.

The project is a reflection of growing Chinese interest in the study of exoplanets. The design of the mission is being led by the China Aerospace Science and Technology Corporation (CASC). The project, if approved following on-orbit testing, will pose numerous technical challenges surrounding formation flying and interferometry aspects of the mission.

The Chinese Academy of Sciences is meanwhile assessing a pair of proposals for exoplanet-seeking space observatory missions under its Strategic Priority Program on Space Science. These are the Closeby Habitable Exoplanet Survey (CHES) and Earth 2.0 (ET) missions. 

CHES would use astrometry, the same technique used by ESA’s Gaia star-mapping space telescope, while ET would use the transit method to monitor 1.2 million dwarf stars.

Andrew Jones covers China's space industry for SpaceNews. Andrew has previously lived in China and reported from major space conferences there. Based in Helsinki, Finland, he has written for National Geographic, New Scientist, Smithsonian Magazine, Sky...