Asteroid mining is the ultimate high-risk, high-reward business. While there are undoubtedly billions—some argue trillions—of dollars' worth of valuable minerals and metals in near-Earth asteroids, a host of questions remain about the practicality of harvesting them. How much technology is required to identify asteroids and extract the materials? How difficult will it be to return them to Earth or other desired destinations? And how much will the upfront costs be?

A few companies, such as Planetary Resources, have begun to try to answer these questions, and it seems the initial responses aren't entirely positive. The venture has decided to put its initial focus on Earth observation rather than deep space asteroid mining. But another asteroid company, Deep Space Industries, appears to be pressing ahead. On Tuesday, that company announced its intent to fly the world’s first commercial interplanetary mining mission, Prospector-1.

Under the company's new timeline, Deep Space Industries plans to launch the Prospector-X mission in 2017 into low-Earth orbit as a technology test bed for further development of low-cost exploration spacecraft. Then, "before the end of this decade," the company would launch Prospector-1 to rendezvous with a near-Earth asteroid and investigate its value as a source of mineral resources.

"Now we can say with confidence that we have the right technology, the right team, and the right plan to execute this historic mission,” said Rick Tumlinson, chairman of the board and co-founder of Deep Space Industries. “Building on our Prospector-X mission, Prospector-1 will be the next step on our way to harvesting asteroid resources.”

The company says its small, 50kg spacecraft will use a water-based propulsion system that expels superheated water vapor to generate thrust. Such a system was chosen because the first product mining companies will seek to extract from asteroids is water. They will hope to re-sell this water to NASA or other space agencies engaged in deep space exploration, as it can be broken down into liquid hydrogen and oxygen, both of which are powerful rocket propellants. Using a water-based propulsion system will also allow the company's prospecting spacecraft to refuel while working. Such an ethos is part of the new space vision to "live off the land" as humans and machines extend further into space.

It is far from clear whether Deep Space Industries will succeed with its Prospector missions or find a way to ever turn a profit from space. But it is good to see some speculative miners getting out there and trying. A space resources 'gold rush' would certainly lower the cost of access to space and jump-start its colonization.