NASA’s New Horizons spacecraft is about to fly past the most distant space rock we have ever visited. Since zooming by Pluto in 2015, the probe has been heading ever further from home, towards a tiny world called 2014 MU69. It is set to arrive on New Year’s Day.
We do know that it is a mere 30 kilometres or so across – less than 2 per cent of Pluto’s diameter – which has made getting there incredibly difficult. “It’s a lot harder than Pluto,” says mission leader Alan Stern. “Instead of being the size of the continental US, it’s the size of Boston. Being 100 times smaller means it’s 10,000 times fainter.”
As happened at Pluto, New Horizons will not be communicating with Earth during closest approach, because it will be focused on gathering all the science it can during the high-speed flyby. Whenever it does turn back to point at Earth to transmit data it will take more than 6 hours for its data to traverse the distance between us. So when are we going to get to find out what MU69 looks like?
WHAT KINDS OF IMAGES OF 2014 MU69 WILL BE AVAILABLE WITHIN DAYS OF THE FLYBY?
The downlinks from New Horizons around its 1 January 2019 flyby of 2014 MU69 will not contain its highest-resolution images. Instead, they will be photos that the team is reasonably confident will contain an image of 2014 MU69. Two “failsafe” downlinks are planned for before the closest approach, and three “New York Times” downlinks are planned over the two days after closest approach. These are Rosetta OSIRIS images of comet 67P/Churyumov-Gerasimenko, scaled to be approximately the same size that the New Horizons images of 67P are expected to be, with some processing to add blur and speckle noise (for a variety of reasons, New Horizons LORRI images of MU69 will not look as crisp as Rosetta OSIRIS images of 67P). They are at a phase angle of 10 degrees, similar to the 11-degree phase at which New Horizons will see MU69 from a distance.
Sources:
http://www.planetary.org/blogs/emily-lakdawalla/2018/what-to-expect-new-horizons-mu69-ultima-thule.html