A newly established US company, Deep Space Industries, Tuesday announced a plan to harvest near-earth asteroids.

It is the second company with such an ambitious plan. Another venture, the Planetary Resources Inc of Seattle, jointly backed by Google founders and explorer and filmmaker James Cameron, went public with proposals for similar mission last year, reported Xinhua.

Deep Space Industries said that it would create "the world's first fleet of commercial asteroid-prospecting spacecraft" and had planned to launch a fleet of asteroid-prospecting spacecraft out into the Solar System to hunt for resources, vowing to develop a "breakthrough process for manufacturing in space".

The company said as a first step of the mission, it would be launching small unmanned probes, named FireFlies and with a mass of about 25 kg, in 2015 on journeys that will last two to six months.

The next step will be sending bigger spacecraft, dubbed Dragonflies, to collect samples and bring them back to the Earth. These expeditions will take two to four years.

"Using resources harvested in space is the only way to afford permanent space development," said David Gump, chief executive officer of Deep Space Industries.

"More than 900 new asteroids that pass near Earth are discovered every year. They can be like the Iron Range of Minnesota was for the Detroit car industry last century - a key resource located near where it was needed. In this case, metals and fuel from asteroids can expand the in-space industries of this century."

Deep Space Industries' move turned the asteroid mining into a two-horse race. Some scientists are highly sceptical of the idea of asteroid mining, though new technologies have made it possible to exploit the rare metals present in the space rocks.