The first successful use of a radio telescope on the moon has kicked off a new era of astronomy that could shed light on the cosmic dark ages – despite a bumpy landing.
NASA’s ROLSES-1 (Radio wave Observations at the Lunar Surface of the photoElectron Sheath) telescope was mounted on the Odysseus lander, an Intuitive Machines spacecraft that made the first ever private lunar landing last year. While Odysseus was the first such spacecraft to survive a landing, it tipped on its side, rendering most of the equipment on board unusable – but the telescope was spared.
“This is the first time that radio astronomy has been done from the moon,” says at the University of Colorado, Boulder, who was part of the team behind ROLSES-1. It consisted of four 2.5-metre-long spring-loaded antennae. Two of the arms accidentally deployed prior to the landing, while the other two were commanded to deploy after the landing.
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That was enough to give the researchers a few hours of observations before Odysseus ran out of power, allowing them to detect radio emissions from Earth and further afield. The observations revealed that, from afar, our planet’s radio signal appears to twinkle because of Earth’s upper atmosphere – something that may also be the case on inhabited alien worlds. “You could use this as a case study when looking for advanced technological life on exoplanets,” says Hibbard.
ROLSES-1 also detected radio signals from elsewhere in the galaxy, the result of high-energy cosmic rays produced by supernovae, black holes and other phenomena interacting with the Milky Way’s magnetic field. The researchers had also hoped to observe radio waves from activity on the sun and Jupiter, but were unsuccessful, as the lander ran out of power. “We missed a solar burst by like a minute,” says Hibbard. “It was really a pity.”
While ROLSES-1 is the first successful radio telescope on the moon, China’s Chang’e-4 mission in 2019 included a similar instrument, but its observations were inconclusive because of noise from the lander. NASA is now set to send many more radio telescopes to the moon, starting with LuSEE-Lite this year, followed by LuSEE-Night and ROLSES-2 in 2026. There are also ambitions to build a massive radio dish in a crater on the moon.
The drive to get these instruments to the moon is because telescopes deployed on the lunar far side can observe the universe unhindered by interference from Earth. That might allow astronomers to detect the first evidence of a faint radio signal from the cosmic dark ages, a period less than a million years after the big bang, before the first stars formed.
“The universe would have been just expanding gas,” says at the University of California, Berkeley. “If we can resolve this feature, it should tell us something about the energy budget of dark matter before there was any astrophysics at all.”
arXiv
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