Charlie K. Ashe | Searcharxiv

arXiv2026

The Lunar Farside Transients and Technology Telescope (LFT3) Mission

We present here an overview of the Lunar Farside Transients and Technology Telescope (LFT3) mission to take advantage of the extremely clear radio frequency environment on the lunar farside. Radio observations performed from the lunar farside effectively and fully mitigate two unavoidable limitations of terrestrial-based radio telescopes: (i) the prevalence of interfering radio transmitters from human activity; and (ii) the impact of the Earth's ionosphere. However, in the era of cost-effective access to the Moon, there are many scheduled lunar missions over the next few years, and the window of opportunity to perform radio interference-free observations from the lunar farside is closing fast. LFT3 is the only mission proposed to go to the lunar farside and exploit this unique opportunity in human history. LFT3 will observe in an uncluttered radio environment to conduct unambiguous technosignature searches, transient surveys, solar physics and planetary emissions studies, spectral line observations, and cosmological science observations. LFT3 will provide an important incumbent use of the microwave spectrum for cislunar radio astronomy.

astro-ph.IM↗

arXiv2026

Modelling Radio Frequency Interference on the Lunar Farside

Technological progress is a double-edged sword in the world of radio astronomy: improvements in antennas, receivers, and digital backends increase sensitivity, but rapid growth in terrestrial and orbital communications has caused a steep rise in radio-frequency interference (RFI). Modern datasets have become increasingly contaminated by RFI that is difficult to remove and can mimic or obscure astrophysical signals, complicating the search for objects such fast radio bursts (FRBs), pulsars, and technosignatures. The lunar farside has such been proposed as a site for radio-quiet observations, motivating missions such as the Lunar Farside Transients and Technology Telescope (LFT3) and others. However, planned lunar missions may introduce intended and unintended radio emissions into this protected environment. We use a LFT3-like instrument to model the evolution of the apparent lunar farside RFI environment over the coming years. Using a planned lunar mission catalogue and models for intended and unintended emissions, we estimate the received RFI over the 0.1-2700 MHz frequency range. We find that while intended emissions are concentrated near communications bands, particularly 2.4-2.6 GHz, unintended emissions contaminate broad regions of the LFT3 band. We further find that, under the assumptions of our model, uniform UEMR shielding of at least 30 dB is required to place the maximum interference below the sensitivity of a LFT3-like instrument; more sensitive telescopes would require higher UEMR shielding. We predict that the lunar farside will remain usable for LFT3-like observations, but will become increasingly contaminated as the lunar satellite population grows. This highlights the decreasing window of opportunity for measurements of the lunar farside's radio quiet environment and should inform future mission design and policy choices for the protection of Moon-based radio science.

astro-ph.IM↗