Yes, we all know Pluto is no longer an official planet, merely a dwarf, but it still enjoyed full planet status when New Horizons rocketed from Cape Canaveral, Florida, on Jan. 19, 2006. Plutos demotion came just seven months later, a sore subject still for many. Were kind of running the anchor leg with Pluto to finish the relay," Stern says. The sneak peeks of Pluto in recent weeks are getting "juicier and juicier," says Johns Hopkins project scientist Hal Weaver. "The science team is just drooling over these pictures."The Hubble Space Telescope previously captured the best pictures of Pluto. If the pixelated blobs of pictures had been of Earth, though, not even the continents would have been visible. The New Horizons team is turning "a point of light into a planet," Stern says. An image released last week shows a copper-colored Pluto bearing a large, bright spot in the shape of a heart. Scientists expect image resolution to improve dramatically by Tuesday. The 7,767-mile span at closest approach is about the distance between Seattle and Sydney. New Horizons, weighing less than 1,000 pounds including fuel, has seven instruments that will be going full force during the encounter. Its expected to collect 5,000 times as much data, for instance, as Mariner 4.Were going to rewrite the book," Weaver says. "This is itthis is our once-in-a-lifetime opportunity to see it."The team gets one crack at this. Were trying to hit a very small box, relatively speaking," says Mark Holdridge, the encounter mission manager. "Its 60 by 90 miles, and were going 30,000 mph, and were trying to hit that box within a plus or minus 100 seconds."The only planet in our solar system discovered by an American, Pluto actually is a mini solar system unto itself. Plutojust two-thirds the size of our own moonhas big moon Charon thats just over half its size, as well as baby moons Styx, Nix, Hydra, and Kerberos. The names are associated with the underworld in which the mythological god, Pluto, reigned. New Horizons will observe each known moon and keep a lookout for more. Scientists involved in the 700 million effort want to get a good look at Pluto and Charon, and get a handle on their surfaces and chemical composition. They also plan to measure the temperature and pressure in Plutos nitrogen-rich atmosphere and determine how much gas is escaping into space. Temperatures can plunge to nearly minus-400 degrees. Bill McKinnon, a New Horizons team member from Washington University in St. Louis, Missouri, expects to see craters and possible volcanic remnants. A liquid ocean and a rocky core may lie beneath the icy shell. Anybody who thinks that when we go to Pluto, were going to find cold, dead ice balls is in for a rude shock," McKinnon says. "Im really hoping to see a very active and dynamic world."Pluto has tantalized astronomers since its 1930 discovery by Clyde Tombaugh using the Lowell Observatory in Flagstaff, Arizona. Some of Tombaughs ashes are aboard New Horizons. His two children, now in their 70s, plan to be at Johns Hopkins for the encounter. With its tilted, elongated 248-year orbit, Pluto has made it only a third of the way around the Sun since its discovery. The amount of sunlight that reaches Pluto is so dim that at high noon, it looks like twilight here on Earth. The massive surrounding Kuiper Belt, in fact, is called the Twilight Zone. The New Horizons team has its eyes on a few much smaller objects in the Kuiper Belt, and is hoping for a mission extension as the spacecraft continues toward the solar system exit on the heels of NASAs Voyagers 1 and 2 and Pioneers 10 and 11.For now, signals take 4hours to travel one way between New Horizons and flight controllers in Maryland. New Horizonsscience instruments will be cranked up to collect maximum data Tuesday, leaving no time to send back data. In fact, scientists wont be absolutely certain of success until Tuesday night, 13 hours following New Horizonsclosest approach, when it "phones home."It will be Wednesday before the closest of Plutos close-ups are available for release. And it will be well into next yearOctober 2016before all the anticipated data are transmitted to Earth. What is the significance of this mission? What do you find extraordinary about it?