Lunar orbiter to listen for radio signals from cosmic "Dark Ages"
The National Radio Astronomy Observatory (NRAO) has announced a new addition to NASA’s upcoming moon-shot Artemis program. From the silent skies on the far side of the Moon, the DAPPER spacecraft will listen out for radio signals from the “Dark Ages” of the universe, before the first stars fired up.
Beginning around 370,000 years after the Big Bang, the universe settled into quite a dull existence. For millions of years after that, pretty much the only things around were huge clouds of hydrogen gas, but as everything started to cool down, pockets of that gas condensed and collapsed to form the first stars and black holes. With those stars came the first ever light, ending the Dark Ages and transitioning to a time often called the “Cosmic Dawn.”
So far, the earliest signal we’ve detected comes from radio waves produced by hydrogen from 180 million years after the Big Bang, likely caused by radiation from the first stars interacting with the hydrogen around them. That means it comes from during the Cosmic Dawn – but can we look even further back in time, to the Dark Ages?
That’s the goal of the Dark Ages Polarimetry Pathfinder (DAPPER). This spacecraft will use a specialized radio receiver and a high-frequency antenna to listen out for faint radio signals from the early universe. It’ll need a very radio-quiet environment to do this, and the other side of the Moon is ideal.
“No radio telescope on Earth is currently able to definitively measure and confirm the very faint neutral hydrogen signal from the early universe, because there are so many other signals that are much brighter,” says Richard Bradley, senior research engineer at NRAO’s Central Development Laboratory (CDL). “At CDL we are developing specialized techniques that enhance the measurement process used by DAPPER to help us separate the faint signal from all the noise.”
And now the NRAO has revealed that DAPPER will be launched as part of NASA’s Artemis program. This program, detailed earlier this week, will see US astronauts return to the Moon in 2024. It won’t be a fleeting visit this time either – the plan is to set up a permanent human presence there, laying the groundwork for eventual crewed missions to Mars.
By making DAPPER part of this program, it should reduce the costs of the mission compared to a standalone project. The plan is to launch DAPPER from the Lunar Gateway, a proposed Moon-orbiting space station that will act much like the International Space Station.
A prototype of the receiver will be designed and developed by NRAO engineers over the next two years, before testing and, hopefully, deployment.