For decades, astronomers have yearned for the day when they could observe the period known as "Cosmic Dawn." This period, which took place roughly 50 million to 1 billion years after the Big Bang, is when the first galaxies in the Universe formed. Observing these galaxies is crucial to understanding cosmic evolution and the forces that govern the Universe (e.g., Dark Matter, Dark Energy, etc.) Thanks to next-generation observatories like the James Webb Space Telescope (JWST), astronomers are starting to get their first look behind the veil.
To get an even better understanding of this cosmological period, scientists from the Royal Astronomical Society (RAS) propose sending the CosmoCube mission to the far side of the Moon. The proposed mission will study the Universe shortly after the Big Bang, before the first stars and galaxies appeared. The concept was presented at the RAS' 2025 National Astronomy Meeting, taking place at Durham University from July 7th to July 11th.
Cosmic Dawn is considered the final frontier of astronomy. Observing this period is a major challenge for astronomers because it coincides with what astronomers call the "Cosmic Dark Ages," a time when the Universe was permeated by neutral hydrogen. The only light sources during this period were the Cosmic Microwave Background (CMB) and photons released by the reionization of neutral hydrogen by the first stars and galaxies. This latter light source is redshifted to the point that it is only visible in parts of the infrared and radio spectrum that are very difficult to observe using modern instruments.
Most of our instruments are subject to a lot of background noise, which makes it difficult to obtain sensitive measurements from this distant cosmic period. On the other hand, the far side of the Moon is not subject to atmospheric or radio frequency interference (RFI). Hence why NASA, the European Space Agency (ESA), the China National Space Agency (CNSA), and other space agencies have proposed building observatories on the far side of the Moon. These plans have become part of multiple lunar exploration programs, including NASA's Artemis Program and China's International Lunar Research Station (ILRS).
Other proposed observatories will investigate phenomena ranging from Fast Radio Bursts (FRBs) and supernovae to radio pulsars. The mission proposed by the RAS would use the Moon's quiet radio environment to listen for an "ancient whisper" from the cosmos. Said Dr Eloy de Lera Acedo, who presented the proposal at the 2025 National Astronomy Meeting:
It's like trying to hear that whisper while a loud concert is playing next door. This makes it really hard to pick up those faint signals from billions of years ago. To detect a special radio signal that comes from hydrogen – the first, most basic and most abundant chemical element – in the early Universe, we need it to be quiet. That's why we're proposing to send a small satellite to orbit the Moon and detect a signal which could hold clues about how everything began and how structures like galaxies eventually formed.
The CosmoCube will consist of a small satellite with a precision-calibrated radiometer operating at low frequencies (10–100 MHz) in lunar orbit. This will allow the mission to detect extremely faint radio signals from the Cosmic Dawn period, which have traveled over 13 billion years to reach us. This mission could shed light on numerous cosmological mysteries, like the Hubble Tension, the discrepancy in the measured rate of cosmic expansion. It could also help astronomers narrow the search for the elusive Dark Matter particle, which accounts for more than 80% of the Universe's mass.
Said Lera Acedo, head of Cavendish Radio Astronomy and Cosmology at the University of Cambridge:
By doing this, CosmoCube aims to help us better understand how our Universe transformed from a simple, dark state to the complex, light-filled cosmos we see today, with all its stars and galaxies. Crucially, it will also help scientists investigate the mysterious dark matter and its role in shaping these cosmic structures.
The Cosmo Cube mission is being developed by a UK-led international consortium with the support of the UK Space Agency's Science Bilateral Program. The project team is already creating functioning prototypes of the instruments it will carry and subjecting them to environmental tests, in collaboration with industry partners like the UK-based company Surrey Satellite Technology Limited (SSTL). The project team envisions the mission being ready to launch in 4 to 5 years, with the ultimate goal of reaching lunar orbit before the end of the decade.
Further Reading: Royal Astronomical Society