A team of British scientists and engineers is to drill three kilometres through the ice of Antarctica to try to find signs of life in a lake buried under a glacier.
The mission will use hot water to melt its way through the ice to reach Lake Ellsworth, which has been isolated from the outside world for at least 125,000 years and possible as long as a million years.
The team hopes to be the first to sample a sub-glacial Antarctic lake.
Lake Ellsworth is thought to be among more than 350 such bodies of water that have remained unfrozen thanks to geothermal heat seeping into them from the Earth's core.
The BBC reports that exploring sub-glacial lakes may help scientists design missions to search for life on other worlds such as Jupiter's moon Europa, which is thought to feature a liquid ocean beneath a thick layer of ice.
The lakes may also hold clues to future climate impacts.
An engineering team leaves the UK later this week along with 70 tonnes of gear needed for the project.