Water is really amazing. It is one of the primary reasons we exist. We need it to live, and many people need to live near it. it is one of our world engines, affecting almost everything we experience from weather to thirst to a relaxing bath. It is absolutely essential to our species.
Water is also essential to space exploration. When searching for life elsewhere in the universe, we typically begin by searching for water. It will satisfy the biological needs of astronauts. It can be used to shield us from cosmic radiation, to grow plants and food, and eventually produce rocket fuel. Our current rockets utilize massive amounts of liquid propellant to escape the earth’s gravity well. This means that launching from the planet’s surface is incredibly inefficient and very expensive. As much as 90% of a rocket’s mass is the propellant, limiting the size of the payload it can actually deliver to space. The solution to this problem is in-situ or space-based fuel production. If we can develop the means to produce fuel in space, we can refuel spacecraft in orbit and eliminate the need to haul huge amounts of fuel from earth’s surface. Producing fuel in this manner is one of the key strategies which will allow humans to become a spacefaring civilization. This is also the exact business plan of one FuelSpace's favorite companies: Shackleton Energy.
Asteroids, comets, moons, and even the atmospheres of other planets are all sources of water that can be mined. It is highly likely that the oceans of our own planet are a result of asteroid and comet strikes during the late heavy bombardment of earth. During this period of time, Jupiter’s gravity created chaos in the asteroid belt and earth was bombarded by millions of asteroids, many containing huge amounts of water in the form of ice. Many scientists now believe this is one of the primary reasons that our planet now holds so much water. This means that asteroids were potentially the seeds for life here on earth.
A large asteroid can potentially hold more freshwater than is found on all of earth, making them extremely attractive targets for water mining. Planetary moons can also hold an abundance of water. Our own moon is thought to contain huge amounts of water in the form of ice sheltered in deep craters on the surface. Such areas are never exposed to the sun and therefore contain vast quantities of minable ice. Jupiter’s moon Europa has been one of the most attractive locations in the solar system in our search for life. Europa took it a step further in 2013 by exposing her undergarmets. Scientists have discovered what they believe are huge geysers of liquid water on Europa.
Water can also be found on planets, and not just in liquid form. The atmospheres of some planets can be used to produce water. Mars is the most likely candidate for human exploration in the near future, and the Martian atmosphere is primarily composed of carbon dioxide. This carbon dioxide can be combined with a small amount of hydrogen brought from earth and, using basic chemical processes, can be used to produce methane and water. Both of which can then be utilized to produce rocket fuel. Here on Earth Natural Gas Vehicles (NGVs), which are powered by methane, are making huge inroads into the commercial fleet markets (trucking, mining, rail, marine, etc.) and rockets are next on the industry's hit list. Liquid methane rocket fuel is less expensive than traditional RP-1 which is derived from oil-based kerosene, and it is also highly abundant in space. In the future, one could easily fuel up liquid methane powered rockets on Saturn's moon Titan. The moon holds vast oceans of liquid methane which will eventually be tapped as a refueling depot. Elon Musk's Rocket Wizards over at at SpaceX have mentioned Methane as a potential fuel for Mars missions, and next year will begin testing a liquid methane powered Raptor engine. The Raptor will be designed as a higher thrust version of the Merlin engine line currently in production on the Falcon 9 rocket.
Water is essential to human survival and will be an integral part of our expansion into space. Lucky for us, it is readily available and throughout our solar system, as long as we know where to look.