According to A Brief History of the Future in 2343 work began on collecting asteroids for water ice:
Ideas had been proposed as far back as the 20th century about using lasers to melt portions of asteroids and focusing the gas to drive them through space. Therefore experimental laser tugs were sent to the Asteroid Belt to bring water ice back to the Moon. The only modification that was made to the three-hundred-year-old design was that a funnel was used to direct the outgoing gases. This meant that the lump could be directed more accurately to its destination without causing too much mass loss.To my surprise, when I researched this topic I found very little on the internet about collecting asteroids made of water ice. I found an article on Popular Mechanic about why it matters that there's so much water in the asteroid belt, but not actually about harvesting asteroids. It seems a lot of the water isn't in frozen form, but embedded in minerals within the rock.
I did find quite a lot about mining asteroids though, which I've written about before. But there is another reason why asteroids are so interesting. According to a recent article on Chemistry World, the website of the Royal Society of Chemistry, asteroids may hold the key to life on Earth.
‘The water and organics on Earth didn’t form with the planet, they came in later on asteroids,’ explains Harold Levison, a chief planetary scientist at Southwest Research Institute, Boulder, US. But we don’t know the details of how this happened or what exactly these asteroids carried with them.There are missions at the moment to take samples of asteroids Ryugu and Bennu.
Ann Marie Thomas is the author of four medieval history books, a surprisingly cheerful poetry collection about her 2010 stroke, and the science fiction series Flight of the Kestrel. Book one, Intruders, and book two Alien Secrets, are out now. Follow her at http://eepurl.com/bbOsyz