While the Eastern Seaboard was starting to stir early Tuesday morning, July 14, hundreds of space scientists working on NASA’s New Horizons mission were wide awake at the Johns Hopkins University Applied Physics Laboratory in Maryland, getting a close-up view of Pluto sent overnight from a spacecraft 3 billion miles away.
Among the awestruck scientists was Rutgers alumnus Matthew Hill, who found the moment a fulfillment of his childhood fascination with space.
While their feet remained planted firmly on Earth, Hill and his colleagues felt like they were riding that grand-piano-sized spacecraft to the outermost reaches of the solar system. Almost two hours later, New Horizons would make its closest approach to Pluto – just 7,800 miles from the dwarf planet’s surface. Its cameras would snap furiously and start sending back even more finely detailed pictures the next day.
The mission to Pluto is a milestone for scientists and space enthusiasts, because now humankind has closely explored every known planet in the solar system.
Hill is the lead instrument scientist for the PEPSSI instrument aboard New Horizons. That instrument – officially the Pluto Energetic Particle Spectrometer Science Investigation – has already detected nitrogen escaping from the atmosphere of Pluto. That finding is already giving scientists new insights into the makeup of the planet’s atmosphere.
“Back when I was a kid in the ‘70s and ‘80s, I was interested in all of this stuff,” said Hill, recalling the Voyager space missions to the solar system’s largest planets: Jupiter, Saturn, Uranus and Neptune. Today both of the Voyager probes send back data from the frontiers of interstellar space.
But Hill’s interests drifted away from space after he graduated from Red Bank Catholic High School in 1989. The Eatontown native took a few years off to play in a heavy metal rock band and then enrolled in Brookdale Community College. When he started at Rutgers in 1994, his focus was not on astronomy but nuclear physics.Still, the expertise he gained at Rutgers put his career back on an interplanetary trajectory.
“I looked for a job the summer before I started graduate school at the University of Maryland,” Hill said. “One of the first people who called me back was the person who ended up being my Ph.D. mentor – Doug Hamilton – and he was working on Voyager.”
Hill worked with Hamilton on energetic particle instruments, which he continues to do today. Those instruments look for pieces of atoms – ions, atomic nuclei and protons.
Detailed photos of Pluto from the closest approach have started to dribble in, but Hill notes that it will take 16 months for the treasure trove of data captured during the hours of closest approach to be sent back to Earth. Because of limited power and the small antenna on the spacecraft, data return to Earth at a pokey one kilobit per second, a speed comparable to early dial-up modems.
But Hill won’t have to wait that long for his data.
“The PEPSSI instrument is not a camera,” he said. “We don’t take up that much bandwidth or data volume, so they’re going to get us out of the way early. We’re actually getting pretty much everything next month.”
He started working on the New Horizons mission in 2007, well after the spacecraft was launched and just as it approached Jupiter. That flyby would give scientists the chance to exercise their instruments and capture more detailed images and measurements of Jupiter than was possible with the comparatively low-tech instruments of earlier missions. Jupiter also gave New Horizons a gravity slingshot boost toward its ultimate target.
Hill appreciates the perspective that older scientists have given him of earlier missions.
“They’d talk about when they were there for the first flyby of Uranus or Jupiter, and I thought that sounded exciting,” he said. “Here’s my chance to be involved in something like that.”
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