Racing to build a radio telescope on the moon

The search for extraterrestrial intelligence (SETI) has faced significant challenges in recent years due to increasing radio frequency interference (RFI) from human technology. The high-energy "Wow!" signal detected in 1977, which sparked interest in this field, would be difficult to detect today amidst the noise of satellites, radar, and other human-made signals.

Additionally, the ionosphere obstructs lower-frequency radio waves, making them harder to detect from the ground. This has led scientists and engineers to propose placing a radio telescope on the far side of the moon, an area free from terrestrial interference.

A new paper by lead author David DeBoer of the University of Oxford and his co-authors proposes a mission called the Lunar Farside Transients and Technology Telescope (LFT3). This mission aims to deploy a sophisticated radio antenna on the moon's far side by the end of the decade, with a budget of $150 million using NASA's Commercial Lunar Payload Services (CLPS) program. The LFT3 telescope would operate across HF, VHF, and UHF frequency bands, scanning the cosmos for 20 weeks.

The mission's primary goals include searching for technosignatures, such as the "Wow!" signal, detecting auroras around exoplanets, and observing fast radio bursts (FRBs) and long-period transients. The extreme temperature fluctuations on the moon's surface, ranging from 120°C during the day to -130°C at night, present engineering challenges that are currently manageable. LFT3 will be designed to withstand these conditions and will monitor for three separate signals.

However, the mission faces another engineering challenge: data transmission. With no direct line of sight from the far side to Earth, LFT3 will need to relay data via an orbiting satellite, limiting data transfer to about 100 GB per month. To address this, the mission planners plan to perform preliminary processing and filtering at the telescope itself, sending only highly relevant data back to Earth. This will require significant radiation-hardened computational equipment, a common requirement for deep-space missions.

As of now, the LFT3 mission has not received any funding. However, given the time limit imposed by increasing lunar mission expansion plans, the relatively affordable price tag of $150 million makes it an appealing opportunity. The success of this one-time mission could significantly enhance radio astronomy and our understanding of the universe.