January 10, 2006
NASA's First Pluto Mission Sets Sights on Solar System's Unexplored Frontier
NASA looks to complete the initial reconnaissance of the planets with the launch this month of New Horizons, the first mission to distant Pluto and the Kuiper Belt. That region of ancient, icy objects is unlike any other worlds in the solar system.
Unlike the inner, rocky planets (like Earth) or the outer gas giants, Pluto is a wholly different type of planet known as an "ice dwarf," commonly found in the Kuiper Belt region billions of miles from the Sun. Pluto and its large moon Charon are the gateway to this mysterious frontier—the National Academy of Sciences has ranked the exploration of Pluto-Charon and the Kuiper Belt among the highest priorities for space exploration, citing the fundamental scientific importance of these bodies to advancing our understanding of the solar system.
"Exploring Pluto and the Kuiper Belt is like conducting an archeological dig into the history of the outer solar system, a place where we can peek into the ancient era of planetary formation," says Dr. Alan Stern, New Horizons principal investigator, from the Southwest Research Institute Department of Space Studies in Boulder, Colorado. "New Horizons represents almost 17 years of work by the scientific community to finally launch a mission to complete the reconnaissance of our planetary system. For the explorer in all of us, New Horizons is a dream come true."
For the first time since Voyager 2 swept past Neptune in 1989, a NASA spacecraft will set its electronic eyes and sensors on a truly new world, a place we've never seen in any detail. "We can only imagine what New Horizons will tell us about this frontier of our solar system—and that's the essence and excitement of exploration," says New Horizons project scientist Hal Weaver of APL.
Designed and built at APL, New Horizons is set to launch from Cape Canaveral Air Force Station, Florida, during a 29-day window that opens January 17, 2006. The compact, 1,050-pound piano-sized probe will lift off aboard NASA's most powerful launch vehicle, the Lockheed Martin Atlas V-551, followed by a boost from a Boeing STAR 48B kick-stage solid propellant motor. It will be the fastest spacecraft ever launched, reaching lunar orbit distance in just 9 hours and passing Jupiter 13 months later.
Lifting off during the first 17 days of its launch window allows New Horizons to fly past Jupiter in early 2007 and use the planet's gravity as a slingshot toward Pluto. The Jupiter flyby trims the trip to Pluto by as much as 5 years—and gives the mission team a chance to test the spacecraft's instruments and flyby capabilities on Jupiter and its intriguing system of moons. The flyby is also an important opportunity for bonus science before New Horizons reaches its primary targets in the Pluto system.
The New Horizons science payload is the most capable suite of instruments ever launched on a first reconnaissance mission to an unexplored planet. It includes imaging infrared and ultraviolet spectrometers, a multi-color camera, a long-range telescopic camera, two particle spectrometers, a space-dust detector, and a radio science experiment. The dust counter was designed and built by students at the University of Colorado in Boulder—the first student-built instrument on a NASA planetary mission. Southwest Research Institute managed development of the science payload.
Depending on when it actually launches, New Horizons could reach the Pluto system as early as mid-2015. It will conduct a 5-month study possible only from the close-up vantage of a spacecraft, characterizing the global geology and geomorphology of Pluto and Charon, mapping their surface compositions and temperatures, and examining Pluto's atmospheric composition and structure. New Horizons will also study the small moons recently discovered in the Pluto system. As part of an extended mission, the team plans to make similar observations at one or more objects in the Kuiper Belt.
The APL team built the spacecraft to handle the long distance and cold conditions at Pluto, which will be more than 3 billion miles (nearly 5 billion kilometers) from Earth when New Horizons arrives. Thermal blankets around the spacecraft retain heat from the operating electronics, keeping onboard temperatures safe without relying on large, excess heaters. New Horizons carries a large 2.1-meter (83-inch) dish antenna, capable of sending science and status data from a range of billions of miles.
The spacecraft will "sleep" in electronic hibernation for much of the cruise to Pluto. Operators will turn off all but the most critical electronic systems and check in with the spacecraft once a year to check out the critical systems, calibrate the instruments and, if needed, perform course corrections. In between checkouts, the spacecraft will send back a beacon signal each week, coded "red" or "green" to give operators an instant read on spacecraft health. Keeping most of the craft in hibernation both lowers the chance of equipment failures and decreases mission operations costs.
The entire spacecraft, drawing electricity from a single radioisotope thermoelectric generator (RTG), operates on less power than a pair of 100-watt household lightbulbs. The instruments collectively draw less than 28 watts and represent a degree of miniaturization unprecedented in planetary exploration.
"This is a once-in-a-lifetime opportunity, in the tradition of the Mariner, Pioneer, and Voyager missions, to set out for first looks in our solar system," says APL's Glen Fountain, New Horizons Project Manager. "Whether you're talking about planets, moons, asteroids, or comets, the great lesson of planetary science is that you never understand a place until you actually go there. When we've gone to each planet we've had to rethink what we thought about the solar system, and the same thing will happen at Pluto."
New Horizons is the first mission in NASA's New Frontiers Program of medium-class spacecraft exploration projects. Stern leads the mission and science team as principal investigator. APL manages the mission for NASA's Science Mission Directorate and will operate the spacecraft in flight. The mission team also includes Ball Aerospace Corporation, the Boeing Company, NASA Goddard Space Flight Center, NASA Jet Propulsion Laboratory, Stanford University, KinetX, Inc., Lockheed Martin Corporation, the University of Colorado, the U.S. Department of Energy, and number of other firms, NASA centers, and university partners.