Scientists using the Hubble Space Telescope have discovered two new objects beyond Pluto for Nasa's New Horizons spacecraft to visit.
Analysis of an initial 200 Hubble images, taken between June 16 and June 26, showed that at least two Kuiper Belt objects might be within range of New Horizons.
"I am delighted that our initial investment of Hubble time paid off," Matt Mountain, director of the Space Telescope Science Institute that oversees Hubble science observations, was quoted as saying.
New Horizons spacecraft, launched in 2006, is on track to become the first probe to visit Pluto in July 2015, some 4.7 billion miles from Earth in the Kuiper Belt.
Nasa has already given go ahead to Hubble Space Telescope to conduct an intensive search for a suitable outer solar system object that the New Horizons (NH) spacecraft could visit after the probe streaks though the Pluto system in July 2015, Nasa said in a statement.
The Kuiper belt is a debris field of icy bodies left over from the solar system's formation 4.6 billion years ago. Though the belt was hypothesized in a 1951 science paper by astronomer Gerard Kuiper, no Kuiper belt objects were found until the early 1990s.
So far over 1,000 Kuiper belt object (KBO) have been cataloged, though it is hypothesised many more KBOs exist.
From June 16 to June 26, the New Horizons team used Hubble to perform a preliminary search to see how abundant small Kuiper belt objects are in the vast outer rim of our solar system.
Hubble looked at 20 areas of the sky to identify any small KBOs. The team analysed each of the pilot program images with software tools that sped up the KBO identification process.
Hubble's sharp vision and unique sensitivity allowed very faint KBOs to be identified as they drifted against the far more distant background stars, objects that had previously eluded searches by some of the world's largest ground-based telescopes.
The Hubble Space Telescope is a project of international cooperation between Nasa and the European Space Agency.