Of our solar system’s nine planets, tiny, frozen Pluto is the only one that’s never been visited by a spacecraft. And at three billion miles away, the runt of the planetary litter is incredibly difficult to study from Earth. But this year NASA and the Johns Hopkins University Applied Physics Laboratory will check the iceball off their exploration agenda as they launch New Horizons–a compact, 1,000-pound spacecraft that they hope will offer some insight into the orb that, right now, is just a blurry smudge of light in the outer reaches of space.

Long-Distance Linkage

New Horizons project manager Glen Fountain stands behind the door of the Mission Operations Center at the Johns Hopkins Applied Physics Laboratory near Baltimore, from which members of the New Horizons team will track all of the spacecraft’s activity. Because the probe will travel about three billion miles to reach Pluto, all outgoing commands and incoming data will be transmitted through NASA’s Deep Space Network of antenna stations.

Testing 1, 2, 3

If the New Horizons mission doesn’t go as planned, researchers will miss their best chance to study Pluto during this lifetime-the planet is now headed toward the farthest-away stretch of its 248-year elliptical orbit around the sun. The spacecraft must endure a barrage of prelaunch tests. Here, the probe sits in its “test yoke” during the mass-properties test, conducted to determine how mass is distributed throughout the craft and to help mission engineers find its center of gravity. The tanks in the foreground supply nitrogen to the air bearings in the mass-properties machine so that the craft literally floats on a cushion of nitrogen.

Keeping the Craft in Line

Yanping Guo, leader of the New Horizons Mission Design Team, stands in front of the 60-foot dish antenna at the Johns Hopkins Applied Physics Laboratory’s Satellite Communications Facility. After launch, Guo and her team, who designed the probe’s path to Pluto, will work with the mission operations and navigation teams to keep New Horizons on track.

Dishing Up the Data

New Horizons will use a “dish stack” of three antennas to transmit information between Earth and its deep-space destination. The most powerful of the three-the high-gain antenna-forms the base of the stack, with a large dish that covers nearly a full side of the probe. The medium-gain antenna, which uses a much smaller dish, rests directly above the high-gain antenna, and the low-gain antenna sits at the top. During testing, the spacecraft team used the gold squares seen on the dish surfaces to align the craft and ensure that it was facing the correct direction.