Scientists in China have proposed building a radio telescope array on the moon’s far side, which, if approved, could become the first operational lunar radio observatory.
The array would consist of 7,200 butterfly-shaped wire antennas to detect ultra-long wavelength cosmic signals that are blocked by the Earth’s atmosphere but are crucial for understanding the early universe, especially the period before the first stars turned on.
While United States scientists have previously proposed similar concepts, China’s version could be built within a decade, leveraging the country’s upcoming robotic and crewed lunar missions, as well as the China-led International Lunar Research Station that is set to take shape by 2035.
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Spanning 30km (18.6 miles) with an effective collecting area of 0.1 sq km, the array would provide resolution and sensitivity high enough to help probe the so-called cosmic dark ages and discover more exoplanets, according to researchers from the China Academy of Space Technology in Xian and the Shanghai Astronomical Observatory.
“The construction of the array will be a highly complex engineering project, involving scientific instruments, relay satellites, robots, lunar surface logistics and communication networks,” the researchers wrote in the latest issue of Chinese Space Science and Technology.
“It will drive innovation across multiple fields, offering high scientific and technological value while strengthening China’s position in deep-space exploration and astronomical research.”
The team did not specify a potential construction site for the array. Finding a large, flat surface in the rugged terrain of the lunar south pole – where the planned research station will be located – could prove challenging.
To overcome technical and logistical hurdles, the researchers proposed a step-by-step approach, with each phase achieving specific scientific goals and testing new deployment technologies.
During the first phase, an initial unit comprising 16 antennas (in a 4×4 configuration) would be deployed by the Chang’e-7 and 8 unmanned missions via lander-based deployment or robotic assembly. With a timeline of one to three years, this phase would mainly map the low-frequency cosmic radio background, laying the foundation for detecting faint signals from the cosmic dark ages.
For the second phase, the array’s core section – about 100 antenna units – would be built using a multi-rocket, multi-payload transport strategy. Astronauts would deploy the antennas during extravehicular activities.
This stage would take three to five years to complete and allow scientists to study the universe’s early history, including the period before the first stars formed and the process that turned hydrogen into glowing gas to light up the universe.
During phase three, the full deployment of all array units would take place with support from the China-led lunar research base. Using multi-lander deployment, the final system would be assembled over five to 10 years, the team estimated.
US researchers have explored similar ideas under Nasa’s Innovative Advanced Concepts Programme. In 2021, Nasa engineers proposed the Lunar Crater Radio Telescope – a 1km-wide dish-shaped telescope inside a crater on the moon’s far side – to be built using wall-climbing robots that would suspend a massive wire mesh.
On Earth, large-scale radio telescope networks, such as the Square Kilometre Array, are being built to achieve high-resolution imaging by linking antennas across vast distances. However, their ability to detect ultra-low frequency signals is severely limited by interference from the Earth’s atmosphere and human-made radio noise.
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