A startup backed by top Google executives and film director James Cameron on Tuesday unveiled a plan to mine asteroids for precious minerals and water.

Planetary Resources used a space museum in the Pacific Northwest city of Seattle as a launching pad for a bold plan to prospect on resource-rich chunks of rock not far from Earth in space.

"The promise of Planetary Resources is to apply commercial innovation to space exploration," said former NASA astronaut Tom Jones, an advisor to the startup.

"They are developing cost-effective, production-line spacecraft that will visit near-Earth asteroids in rapid succession, increasing our scientific knowledge of these bodies and enabling the economic development of the resources they contain."

Planetary Resources said that it was "poised to initiate" space mining missions in what it predicted would become a multibillion dollar industry.

A single 500-meter platinum-rich asteroid contains the equivalent of all the Platinum Group Metals mined in history, according to the startup, whose backers include Google co-founders Larry Page and and Eric Schmidt.

"Many of the scarce metals and minerals on Earth are in near-infinite quantities in space," said Planetary Resources co-founder Peter Diamandis, who created the X Prize.

"As access to these materials increases, not only will the cost of everything from microelectronics to energy storage be reduced, but new applications for these abundant elements will result in important and novel applications."

Water-rich near-Earth asteroids (NEAs) could be springboards for deep space exploration by serving as fueling and supply depots, according to the startup.

"Water is perhaps the most valuable resource in space," said Planetary Resources co-founder Eric Anderson.

"In addition to supporting life, water will also be separated into oxygen and hydrogen for breathable air and rocket propellant."

More than 1,500 of the approximately 9,000 known NEAs are as reachable as the moon in terms of how much energy it would take for the trip, according to the startup.

The company has developed the first in what it said will be a family of prospecting spacecraft dubbed Arkyd-100 Series.

"Our mission is not only to expand the world's resource base," said Planetary Resources chief engineer Chris Lewicki.

"We want to increase people's access to, and understanding of, our planet and solar system by developing capable and cost-efficient systems."