After almost two months, the New Horizons probe has sent back the clearest images of Ultima Thule to date – which are, most likely, the clearest we'll ever get. The new images were snapped just minutes before the spacecraft made its closest pass of the Kuiper Belt object on January 1, in what the science team calls a risky "stretch goal" of the project.
To those who have been following the drip-feed of data and photos of Ultima Thule, the new shots look pretty similar to the last batch. But they're actually about four times sharper, with a spatial resolution of just 110 ft (33 m) per pixel. The science team notes that this is the highest spatial resolution of any images ever snapped by New Horizons – after all, the craft flew three times closer to Ultima Thule than it did to Pluto during that 2015 flyby.
These new shots were taken about six and a half minutes before New Horizons's closest pass of Ultima Thule, when the craft was 4,109 mi (6,628 km) from the object. Getting such sharp images from that close is incredibly impressive when you remember that New Horizons was zipping past at over 32,000 mph (51,500 km/h). Training its cameras onto a relatively small object at that speed is no small feat, let alone managing to get such high resolution snaps out of it.
"These 'stretch goal' observations were risky, because there was a real chance we'd only get part or even none of Ultima in the camera's narrow field of view," says Alan Stern, Principal Investigator of the New Horizons project. "But the science, operations and navigation teams nailed it, and the result is a field day for our science team! Some of the details we now see on Ultima Thule's surface are unlike any object ever explored before."
These new shots bring the odd landscape of Ultima Thule into sharper focus. Along with the large crater on the smaller lobe, the images highlight the smaller pits along the top, at the night/day border, in more detail. The mysterious bright spots also stand out more, especially the "collar" where the two lobes meet.
New Horizons may have completed its flybys of Pluto and Ultima Thule, but the spacecraft isn't done yet. It will continue to examine other Kuiper Belt objects, and although it'll be from a much longer distance than it did Ultima, it should still be able to see them in higher detail than Hubble. There's even a chance that another flyby target could be found.
In the meantime, data and images are set to continue pouring in until mid-2020, so we may not have seen the last of Ultima Thule.