Space, it has been said, is big. Really big.

But big enough for two companies that want to mine near-Earth asteroids?

A venture announced Tuesday in California hopes so.

Deep Space Industries says it wants to start sending miniature scout probes, dubbed "Fireflies," on one-way missions to near-Earth asteroids as soon as 2015. Larger probes, "Dragonflies," that will bring back 50- to 100-pound samples from prospective targets could be on their way by 2016, company CEO David Gump told reporters.

The goal is to extract metals, water and compounds that can be used to make spacecraft fuel from the chunks of rock that float within about 50 million kilometers (31 million miles) of Earth. Gump said the ability to produce fuel in space would be a boon for NASA, as the U.S. space agency shifts its focus toward exploring deeper into the solar system.