Pluto nearly fills the frame in this image from the Long Range Reconnaissance Imager (LORRI) aboard NASA's New Horizons spacecraft, taken on July 13, 2015.
NASA has selected the potential next destination for the New Horizons spacecraft after its historic July 14 flyby of the Pluto system - a planetoid that lies nearly a billion miles beyond the dwarf planet.
This remote Kuiper Belt object (KBO) known as 2014 MU69 was one of two identified as potential destinations and the one recommended to NASA by the New Horizons team.
Although NASA has selected 2014 MU69 as the target, as part of its normal review process the agency will conduct a detailed assessment before officially approving the mission extension to conduct additional science.
"Even as the New Horizon's spacecraft speeds away from Pluto out into the Kuiper Belt, and the data from the exciting encounter with this new world is being streamed back to Earth, we are looking outward to the next destination for this intrepid explorer," said John Grunsfeld, chief of the NASA Science Mission Directorate at the agency headquarters in
Washington.
"While discussions whether to approve this extended mission will take place in the larger context of the planetary science portfolio, we expect it to be much less expensive than the prime mission while still providing new and exciting science," said Mr Grunsfeld.
Like all NASA missions that have finished their main objective but seek to do more exploration, the New Horizons team must write a proposal to the agency to fund a KBO mission.
That proposal - due in 2016 - will be evaluated by an independent team of experts before NASA can decide about the go-ahead.
Early target selection was important; the team needs to direct New Horizons towards the object this year in order to perform any extended mission with healthy fuel margins.
New Horizons will perform a series of four manoeuvres in late October and early November to set its course towards 2014 MU69 - nicknamed "PT1" (for "Potential Target 1") - which it expects to reach on January 1, 2019.
Any delays from those dates would cost precious fuel and add mission risk, NASA said.
New Horizons was originally designed to fly beyond the Pluto system and explore additional Kuiper Belt objects.
The spacecraft carries extra hydrazine fuel for a KBO flyby; its communications system is designed to work from far beyond Pluto; its power system is designed to operate for many more years; and its scientific instruments were designed to operate in light levels much lower than it will experience during the 2014 MU69 flyby.
Scientists estimate that PT1 is just about 45 kilometres across; that's more than 10 times larger and 1,000 times more massive than typical comets, but only about 0.5 to 1 per cent of the size (and about 1/10,000th the mass) of Pluto.
As such, PT1 is thought to be like the building blocks of Kuiper Belt planets such as Pluto.
Unlike asteroids, KBOs have been heated only slightly by the Sun, and are thought to represent a well preserved, deep-freeze sample of what the outer solar system was like following its birth 4.6 billion years ago.