CosmoCube is roughly the size of a small carry-on suitcase and will use the Moon as a shield to listen for a signal from the earliest period of the universe.
The CosmoCube mission has received funding from the UK Space Agency and hopes to launch within the next five years, according to Nature Astronomy.
Led by the University of Cambridge, the international team is seeking a signal from the first days of nuclear fusion in stars.
Hearing the hydrogen line
Also known as the 21 centimetre line, this refers to a radio frequency emitted by hydrogen atoms from the cosmological ‘dark ages’, between the Big Bang and Cosmic Dawn, where reionisation occurred.
This signal is over 13.5 billion years old and is particularly difficult to pick up with Earth-based detection, due to interference from FM radio, satellites and telecommunications drowning it out.
“This emission from hydrogen after the Big Bang, but before the first stars, will hopefully allow us to understand the role of dark matter in the early universe, how it worked to pull together hydrogen into the first stars and galaxies,” said lead author Professor Eloy de Lera Acedo from Cambridge’s Cavendish Laboratory.
The Moon will function as a natural shield for the satellite
As Cosmocube’s orbit passes the far side of the Moon, there will be 40 minutes of protection from Earth’s racket. Over a planned two-year mission of two-hour orbits, the satellite will build up thousands of hours of data, operating at extremely low frequencies – between 10 and 50 MHz, safely outside the range of ground-based telescopes.
“There’s no other place where you can get the sort of shielding you need to detect such a faint signal, while at the same time looking at the whole of space,” said de Lera Acedo, who is also affiliated with the Kavli Institute for Cosmology. “The far side of the Moon is really the only option: it solves multiple problems at once, opening a clear window to the very early universe.”
When in orbit, CosmoCube will unfold a lightweight radio antennae to detect the signal. CosmoCube will monitor and correct its own electronics with a ‘Dicke switched’ calibrator to cancel out drifts and noise inside the satellite to ensure the data is as accurate as possible.
Back on Earth, the data will be evaluated with advanced Bayesian statistical methods to remove foreground noise, such as radio emissions from our galaxy. Computer simulations and in-flight measurements will also be used to reconstruct how the antennae respond to different parts of the sky and space to further clean up any remaining distortions.
“Aside from the science, what makes our mission unique is its size: we’re probing the earliest, deepest parts of the dark ages that others don’t reach, but with a compact, relatively low-cost platform,” said de Lera Acedo.
A state-of-the-art small satellite
The mini satellite features a state-of-the-art fully integrated miniature radiometer, using the so-called RF-Systems-on-Chip (RFSoCs). The CosmoCube space platform (‘SSTL-21’) is being developed in the UK by Surrey Space Technology Limited (SSTL), which specialises in the manufacturing of small satellites.
“CosmoCube is aiming to do some ambitious science from a very small satellite in a challenging environment, and to do that requires some clever design techniques,” said co-author Dr Will Grainger from STFC RAL Space. “We’ve worked with the project partners to develop representative models of the satellite and its payload. These have been tested in our facilities to ensure the thermal performance allows the payload to operate and perform the required sensitive measurements under the different temperature conditions it will experience whilst in orbit around the Moon. In the future, we hope to further develop the full payload in preparation for a full mission.”
“This could be a real UK success story: the hardware, the software, the implementation and the technology is all being developed here, and it could help us answer one of the most profound questions in the universe,” said de Lera Acedo.
