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December 27, 2018

The PI's Perspective: Anticipation on Ultima's Doorstep!

The New Horizons spacecraft is healthy and on final approach to the first close-up exploration of a Kuiper Belt object in history, and the farthest exploration of any world, ever.

In just a few days, on New Year's Eve and New Year's Day, New Horizons will swoop three times closer to our target—2014 MU69 (nicknamed Ultima Thule)—than we flew past Pluto. The anticipation is palpable now: we are on the verge of an important scientific exploration almost 20 years in the making and, in many ways, unlike any other ever attempted.

I'm writing this just days before the New Horizons flyby of "Ultima," and will be my last until the flyby is completed. The pace of activity here at mission control at the Johns Hopkins Applied Physics Laboratory is intense. Mission operations, encounter operations, navigation operations, and science team efforts are all proceeding in parallel, along with an increasing pace of public affairs and engagement activities. Given that pace, here are some updates to help you prepare for and be involved in next week's historic flyby:

• We continue to receive and analyze optical navigation images of Ultima made daily on New Horizons. These images, combined with radio tracking of the spacecraft, help our navigators determine if we need to update files on the spacecraft's main computers to improve our flyby observation pointing and closest approach timing. The final chance to update these files occurs only a day before the flyby itself.


• The highest resolution imagery we are attempting—an eye-popping 35 meters (about 115 feet) per pixel—is a stretch goal, requiring us to know exactly where both Ultima and New Horizons are as they pass one another at over 32,000 mph in the darkness of the Kuiper Belt. (And by the way, out there the Sun is only about as bright as a full moon on Earth, so Ultima is only very, very faintly lit). If we succeed at this observation, we'll have far better imaging resolution of Ultima than we got at Pluto (where best resolution was 70-80 meters, or 230-260 feet, per pixel). If we don't, other imaging observations will still exceed most of the Pluto imaging. And while we don't want to fail, you should know that that these stretch-goal observations are risky. But with risk comes reward, and we would rather try than not try to get these, and that is what we will do.

To pick up for NASA TV, we're providing coverage of our flyby events and press conferences on several channels, including the mission website (https://pluto.jhuapl.edu), the Johns Hopkins Applied Physics Lab's YouTube channel (https://www.youtube.com/user/jhuapl), APL's Twitter feed (@jhuapl). We've posted the schedule of events and channels at https://pluto.jhuapl.edu/News-Center/Where-to-Watch.php; bookmark that page and check back for updates!

As New Horizons closes in on Ultima these final few days before closest approach, our team and people across the world are anticipating the flyby and its scientific results. What will we find when we explore an ancient building block of planets so very well preserved since the dawn of our solar system, 4.5 billion years ago when it was created? No one knows. But soon we will know, beginning in just days!

And that's my final report before the flyby of Ultima on New Year's Eve and New Year's Day. I hope you'll always keep exploring — just as we do!

–Alan Stern