NASA’S NEW HORIZONS spacecraft, launched in January 2006, is closing in on its primary target, the dwarf planet Pluto. Arrival at the icy outer world is on track for 14 July 2015.
But when it reaches Pluto, New Horizons won’t be able to stop and admire the scenery. By necessity (ie. orbital mechanics and the fact that it doesn’t have a rocket motor to slow itself down) it will go sailing straight past, after having given us our first-ever close up glimpse of what used to be called the ninth planet. (I still do call it the ninth planet. Ed.)
This was always the plan. And the plan also calls for a second stage for the mission – a visit to one or more other icy worlds that orbit the Sun far beyond Pluto.
They’re called Kuiper Belt objects (KBOs), as they belong to a family of small, ice bodies that live in that part of the Solar System, called the Kuiper Belt.
The aim is to redirect New Horizons – once it has passed Pluto – onto a course that will take it near one or more of these KBOs.
But even though astronomers have been hunting for candidate KBOs for some years, they’ve yet to find one that is in the right place for New Horizons to visit. Yet there are probably some there that they just can’t see at the moment. So they’ve put out a call for help from the telescope best suited to spot any hidden KBOs – the Hubble Space Telescope.
This week, the Hubble Space Telescope Time Allocation Committee – the body that decides who gets to use the telescope – has recommended it be pressed into service.
The telescope will examine a small region of space to see if it can spot any KBOs. The first step will be doing a pilot study to see if Hubble can indeed spot KBOs in that region and at that distance – 8 billion kilometres from the Sun.
If it finds any, that will give the astronomers enough confidence to push ahead with a deeper, longer search to find the candidate KBOs for New Horizons to visit.
Image courtesy NASA.