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October 22, 2019

The PI's Perspective: Looking Back and Exploring Farther

University of Colorado "Pluto at perihelion party" flyer. (Courtesy of Fran Bagenal)

New Horizons and its seven scientific instruments are healthy and performing well. As our spacecraft plows ever deeper into the Kuiper Belt – billions of miles from home – we continue to collect many kinds of new data.

But before I say more about that, I want to reflect a little. Precisely 30 years ago last month, in September 1989, Pluto passed its perihelion, which means it passed as close to the Sun as it ever gets. While perihelion is still almost 3 billion (!) miles away, it still represented the easiest time to reach Pluto. After all, its farthest point from the Sun is almost 5 billion miles away! Back in 1989, the Pluto science community celebrated the perihelion passage with parties (like the one whose flyer is shown here) and hoped for a future mission to explore this distant planet.

In those intervening 30 years we prevailed to see a mission to explore Pluto funded, designed, launched and flown across the solar system. That mission went through many iterations but ultimately came to be known as New Horizons. The result of New Horizons' brief but powerful flyby is that we now know more about Pluto after its initial exploration that we did about any other planet when it was first explored. We know so much, in fact, that we long for a follow-up orbiter to answer the many questions and quandaries that New Horizons raised by becoming the first mission there.

But I digress; the subject of if and when we fly a follow-up orbiter mission to Pluto is a subject for the next Planetary Decadal Survey. What I want to tell you about next is what has been taking place on New Horizons since I last wrote, and what is immediately ahead.

Most of our current operations involve the continued downlink of 2014 MU69 flyby data to Earth, which will go on for at least another year. But we're also taking new data at a fast clip. Last month we observed a variety of Kuiper Belt objects (KBOs) and dwarf planets in the distance for comparison to both MU69 and Pluto.

Our view of Pluto has expanded since 1989 from a distant point of light to a planet we now know to be a scientific wonderland. See the online version of this map at nationalgeographic.com (Credit: National Geographic)

We also conducted a thorough calibration campaign of all seven scientific instruments, so that we can make the most of the observations of MU69 and more distant worlds. This was the first complete instrument calibration campaign on New Horizons since shortly after the Pluto flyby. These complex calibrations, which our team designed, built and then tested for months before they were carried out, performed flawlessly. They will be transmitted to Earth over the next year, along with the remaining MU69 data and new Kuiper Belt science observations.

Another important activity was the upload of new, more capable software to the Long Range Reconnaissance Imager (LORRI), the telescopic CCD camera aboard New Horizons. This upgrade allows LORRI to take longer exposures and detect fainter science targets than ever before. We transmitted the software in July and tested it – successfully -- in early September. Starting in December, when we next make KBO observations, this new capability will be in regular use for KBO exploration!

There's a lot of activity on the science front too. First up are continued, essentially 24/7, plasma and dust observations of the outer heliosphere in the Kuiper Belt. These unique measurements improve on what the Voyagers collected when they traversed the same distances from the Sun in the 1990s and 2000s, because the instruments aboard New Horizons were built so much later and are therefore much more capable than their Voyager counterparts. But in addition, the New Horizons plasma and dust observations teach us about how that environment modifies the surfaces of KBOs and dwarf planets – adding to the storehouse of knowledge about the worlds in the solar system's third zone, the Kuiper Belt.

We also just this month delivered a new set of MU69 flyby and other data to the open-source NASA Planetary Data System, or PDS. After peer review, the PDS will release these New Horizons data for anyone in the word to access!

And we also recently had a new suite of Pluto surface feature names approved. Key individuals and missions that paved the way for the historic exploration of Pluto and the Kuiper Belt were honored in these 14 Pluto feature names. Read more about the names here and see the map below.

Newly named official features on the map of Pluto. (Credit: NASA/Johns Hopkins Applied Physics Laboratory/Southwest Research Institute/Ross Beyer)

Coming next? As alluded to, in December we plan on making some distant KBO observations we didn't even know were possible until September. We'll get a relatively close look at one KBO (though it will still be just a point of light), and we'll observe another at a different viewing geometry to see how its surface scatters light – and give us insight into surface properties like its porosity and roughness.

And if that wasn't enough, our science team reported dozens of new results at last month's Division for Planetary Sciences meeting, and we and the broader scientific community are preparing to submit almost 20 new research papers on Pluto and MU69 to the planetary science journal Icarus.

And that's my report for now. I plan to write again in a few months. Meanwhile, I hope you'll keep on exploring — just as we do!

–Alan Stern

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