NASA's Hubble Telescope revealed the presence of three Kuiper Belt objects (KBOs) that could be a potential destination for the New Horizons spacecraft after it visits Pluto in July of 2015.

A Kuiper Belt is an object made up of primordial debris, none of these KBOs have ever been visited by an Earthly spacecraft, NASA reported.

"This has been a very challenging search and it's great that in the end Hubble could accomplish a detection - one NASA mission helping another," said Alan Stern of the Southwest Research Institute (SwRI) in Boulder, Colorado, principal investigator of the New Horizons mission.

KBOs are about 10 times larger than the typical comet, but only about 1 or 2 percent the size of Pluto. Since they have not been heated by the Sun, KBOs are in a state of deep-freeze preservation which could allow researchers to gain insight into how our universe looked as far back as 4.6 billion years ago. 

The research team started searching for KBOs back in 2011 using large ground-based telescopes; they succeeded in finding a few, but none that would be reachable with the fuel supply aboard the New Horizons spacecraft. By this September the team had finally identified one KBO that would be "definitely reachable" and two others that were most likely able to be explored. 

"We started to get worried that we could not find anything suitable, even with Hubble, but in the end the space telescope came to the rescue," said New Horizons science team member John Spencer of SwRI. "There was a huge sigh of relief when we found suitable KBOs; we are 'over the moon' about this detection."

KBOs are extremely small and faint, so the finding of these objects was the result of a "needle-in-haystack" search. The three target KBOs are about 1 billion miles past Pluto, and are between 15 and 32 miles across.

The New Horizons team expects to submit such a proposal to NASA in late 2016 for an extended mission that will allow them to fly by one of the KBOs in question.