NASA’s New Horizons Spacecraft Sends Signal From Pluto to Earth

NASA's New Horizons is the first spacecraft to explore Pluto up close. Use the resources below to make the most out of this historic event - humankind's first close up view of this cold, unexplored world in our solar system.

 In July 2015, NASA — and the United States — will complete the reconnaissance of the planets by exploring the Pluto system with New Horizons. The fastest spacecraft ever launched, New Horizons has traveled more time and distance — more than nine years and three billion miles — than any space mission in history to reach its primary target. Its flyby of Pluto and Pluto’s system of at least five moons on July 14 will complete the initial exploration of the classical solar system while opening the door to an entirely new realm of mysterious small planets and planetary building blocks in the Kuiper Belt. The flyby will also cap a five-decade-long era of solar system reconnaissance that began with Venus and Mars in the early 1960s, and continued through first looks of Mercury, Jupiter and Saturn in the 1970s and Uranus and Neptune in the 1980s. Meaningfully, the July 14 flyby of Pluto will occur 50 years to the day after humans first explored Mars with NASA’s Mariner 4 on July 14, 1965.Reaching this “third” zone of our solar system — beyond the inner, rocky planets and outer gas giants — has been a space science priority for years, because it holds building blocks of our solar system that have been stored in a deep freeze for billions of years. In the early 2000s the National Academy of Sciences ranked the exploration of the Kuiper Belt — and particularly Pluto and its largest moon, Charon — as its top priority planetary mission for the coming decade. New Horizons — a compact, lightweight, powerfully equipped probe packing the most advanced suite of cameras and spectrometers ever sent on a first reconnaissance mission — is NASA’s answer to that call. Pluto, the largest known body in the Kuiper Belt, offers an extensive nitrogen atmosphere, complex seasons, strangely distinct surface markings, an ice-rock interior that may harbor an ocean, and at least five moons for study. Among Pluto’s five moons, its largest — Charon — may itself sport an atmosphere or an interior ocean, or both, and possibly even evidence of recent surface activity. The smaller moons (named Nix, Hydra, Styx and Kerberos) are scientifically valuable bonuses, since New Horizons officially began in 2001 as a mission to just Pluto and Charon, years before the four smaller moons were even discovered.

Hazards to flight may exist in the Pluto system due to debris ejected from Pluto’s small satellites. New Horizons mission planners are conducting an intensive search for hazards in May and June 2015 and are prepared, in the unlikely event that significant hazards are found, to divert the craft’s trajectory or use its dish antenna as a shield to protect the spacecraft. New Horizons’ six-month encounter with the Pluto system started in January 2015 and culminates in the July flyby. Its suite of seven science instruments — which includes cameras, spectrometers, radio science, and plasma and dust detectors — will map the geology of Pluto and Charon; map their surface compositions and temperatures; examine Pluto’s atmosphere and search for an atmosphere around Charon; study Pluto’s smaller satellites; and look for rings and new satellites around Pluto. Teams operating and navigating the spacecraft have been using ever-improving imagery from New Horizons to refine their knowledge of Pluto’s location and skillfully guide New Horizons toward a target point about 7,750 miles (12,500 kilometers) from Pluto’s surface. That targeting is critical, since the computer commands that will orient the spacecraft and point its science instruments are based on knowing the exact time and place that New Horizons passes Pluto. And the work doesn’t end with this July’s flyby. Because it gets one shot at its target, New Horizons is designed to gather as much data as it can, as quickly as it can — taking about 100 times more data on close approach than it can send home before flying away. Although the spacecraft will send select, high-priority datasets home in the days just before and after close approach, the mission will continue returning the data stored in onboard memory for a full 16 months.