Pluto: What a Journey!

This blog is from Hal Weaver, who joined the New Horizons team in May 2002, his first assignment after taking a job at the Johns Hopkins University Applied Physics Laboratory. He started out as the principal investigator for the LOng Range Reconnaissance Imager (LORRI) and in 2003 became the New Horizons project scientist.

Now that most of the New Horizons science data have been downlinked to Earth, it seems only fitting to reflect on the long journey that took us to the frontier of our solar system. Below are some personal memories I’d like to share about this incredible voyage of discovery.

The pre-launch years were a time of intense activity for the New Horizons project. As soon as New Horizons received its funding in 2002, the team worked feverishly to deliver the spacecraft to Kennedy Space Center in time for the earliest possible launch window and the shortest flight time to Pluto. As we struggled to deliver the systems and instruments to the spacecraft during the spring of 2005, the payload team started having Sunday morning telecons to stay on track. This was typical behavior across the New Horizons project—people doing whatever it took to meet the looming deadlines. A camaraderie developed that would sustain us throughout the entire mission, and I feel privileged to have worked with such an outstanding group of engineers, managers and scientists.

The New Horizons spacecraft was shipped to Kennedy Space Center/Cape Canaveral Air Force Station in September 2005, where various tests were run to demonstrate readiness for launch. We passed the Mission Readiness Review with flying colors on Dec. 13, 2005. But there was still some high drama during NASA’s Flight Readiness Review at the Cape in January 2006, when a launch vehicle technical issue threatened an indefinite delay. Fortunately, the NASA administrator ultimately decided it was safe to launch, and away we went on Jan. 19, the fastest spacecraft ever to leave the Earth! Watching the picture-perfect launch of New Horizons with the rest of the science team, and then hugging each other as we savored the moment, was one of my favorite experiences during the mission.

New Horizons Spacecraft launch
The left image shows the New Horizons spacecraft during testing at Kennedy Space Center in fall 2005. At right, New Horizons lifts off from Cape Canaveral Air Force Station on Jan. 19, 2006. Credit: NASA

The aperture door of the LOng Range Reconnaissance Imager (LORRI) was finally opened Aug. 29, 2006, and its first images of a star cluster looked great. But in early September, the New Horizons Guidance and Control system’s lead engineer appeared ashen-faced at my office door announcing that LORRI had accidentally been pointed at the sun. Anyone who has worked with telescopes knows that focusing sunlight on a sensitive detector can overheat and destroy the detector. Fortunately, the sun was only briefly slewed across the LORRI detector, and LORRI survived without any degradation in performance. This experience was a poignant reminder that constant vigilance would be needed to ensure a successful Pluto flyby.

The Pluto encounter in July 2015 was the highlight of the New Horizons mission, with enough memories to fill an entire book. But I truly will never forget the scene in my office just after midnight on July 13, when I displayed on my computer screen the last full-frame image of Pluto taken by LORRI, which had just been downlinked from the spacecraft. There were five other colleagues in my office – the team that produced the beautiful color images displayed for the world the next morning – and we all gasped at the iconic “heart” of Pluto and marveled at the diversity of the terrain surrounding it. During media interviews leading up to the encounter, I frequently stated that an important objective of the New Horizons mission was to transform Pluto from the pixelated view seen from Earth into a real world, with complexity and diversity. As the figure below demonstrates, mission accomplished!

The Pluto image to the left was taken by the Faint Object Camera of the Hubble Space Telescope in 1994 and is representative of the highest resolution achieved from Earth. The Pluto image to the right was taken by New Horizons just 16 hours before closest approach in July 2015. This LORRI image is the raw, compressed version seen by New Horizons scientists shortly after midnight on July 13, but it still clearly demonstrates the dramatic increase in science content available from a flyby mission. Credits: NASA/ESA/A. Stern and M. Buie (left image); NASA/JHUAPL/SWRI (right image)

I can’t believe a year has passed since NASA’s New Horizons spacecraft successfully executed its historic encounter with the Pluto system. People around the world have been captivated by the incredible new views of Pluto and its moons provided by New Horizons. As much as I love planetary astronomy and spacecraft missions, I love my family even more and want to thank them for their support while I indulged my scientific passions.

I’m deeply appreciative of the opportunity to participate in this grand adventure, and I’m looking forward to the January 2019 New Horizons encounter with the Kuiper Belt object 2014 MU69, which might be the most primitive body ever visited by a spacecraft.

Hal Weaver
New Horizons Project Scientist Hal Weaver
Credits: JHUAPL/Mike Buckley