Billionaire investors in a small, Seattle-area company that aims to one day mine resources on asteroids have not been deterred by an unmanned rocket explosion that destroyed their test satellite, the company said on Wednesday.

Privately held Planetary Resources counts Google Inc Chief Executive and co-founderLarry Page and Chairman Eric Schmidt among its backers, along with Virgin Group founder Richard Branson, Ross Perot Jr., former Microsoft Corp executive Charles Simonyi and John Whitehead, the former chief executive of Goldman Sachs Group Inc.

"Everyone knows what we are doing is audacious; if we didn't have some failures now and then it would be stunning," said Chris Lewicki, president and chief engineer at Planetary Resources.

"Fortunately we have got some very supportive and visionary investors," he said. "They know we're in this for the long run and we've already moved on to the next thing."

The Redmond, Washington-based company makes a profit from technology contracts with NASA and other private customers, involving propulsion and instruments, Lewicki said.

It plans to eventually extract water, fuel and minerals from asteroids near Earth. But as an interim step, it is developing small satellites with miniature sensors that can communicate with Earth to test its technology.

Rather than using dedicated launch vehicles that can cost millions per launch, Planetary Resources satellites are small enough "to hitch a ride into space with larger, primary payloads," the company said.

That's how the Arkyd 3, a 12-inch by 4-inch unit weighing 10 pounds, came to be aboard the Antares rocket that exploded on Tuesday.

The rocket was built and launched by Orbital Sciences Corp and was mainly intended to carry a Cygnus cargo ship with supplies for the International Space Station.

Lewicki said Arkyd 3 was insured, but he declined to give details.

In any case, the setback will not affect the development of its next satellite, known as the Arkyd 6, which has been in development for several months and will be about twice as large as Arkyd 3, he said.

The company achieved "most of our objectives" with Arkyd 3, the company said.

Arkyd 6 is scheduled for launch in the third quarter of next year, and Planetary Resourceswill use Spaceflight Services Inc of Tukwila, Washington, to configure the ride on a commercial launch vehicle in the United States.

A6 is an "engineering demonstrator" that will orbit earth and is designed to test software, computing systems and the satellite's ability to know where it is pointed and to maneuver, Lewicki said.

Eventually, he added, the company plans to create the Arkyd 300 Series Rendezvous Prospector, which will actually orbit target asteroids.