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Barring any unfortunate surprises, New Horizons is now studying the Pluto system up close with seven different science instruments, including cameras capable of picking out features on the dwarf planet's surface as small as the ponds in New York City's Central Park.

The spacecraft's observations will help researchers map the surfaces of Pluto and Charon in detail; characterize the two bodies' geology; and shed light on Pluto's wispy, dynamic atmosphere, among other things.

Researchers said they can't wait to get a look at the close-approach data. Their appetites have been whetted by observations gathered over the past few weeks showing that Pluto and Charon are complex worlds with surprisingly diverse surfaces.

For example, Pluto sports a polar ice cap and a huge, bright, heart-shaped feature, as well as a giant dark patch mission scientists have dubbed "the whale." Charon, for its part, is scored by craters and canyons, and harbors an enigmatic, 200-mile-wide (320 km) dark blotch at its north pole.

"The Pluto system is enchanting in its strangeness, its alien beauty," Stern said Monday (July 13) during a NASA news conference. "We are already seeing complex and nuanced surfaces that tell us of a history for these two bodies [Pluto and Charon] that is probably beyond our wildest dreams on the science team."

New Horizons is now operating in a nine-day-long "close encounter mode" that runs through Thursday (July 16). But don't expect a big data dump at the end of the week: It will take New Horizons up to 16 months to beam all its observations home. And team members won't even know if the flyby was successful until about 9 p.m. EDT tonight (0100 GMT Wednesday), when the probe's handlers expect to receive a check-in message. (New Horizons can't simultaneously gather observations and send information back to Earth.)

That status update will likely quell a bit of nervousness among the team members, because New Horizons is traveling so fast — 30,800 mph (49,570 km/h) relative to Pluto — that a collision with a piece of debris in the dwarf planet system as small as a grain of rice could be fatal. [New Horizons Wears 'Bulletproof Vest' (Video)]

Analyses suggest that dire outcome is extremely unlikely — but it's possible nonetheless.

"Formally, we're able to set model limits at around 1 in 10,000 [odds] that the spacecraft will be lost due to a debris strike," Stern said during Monday's news conference. "But we've also been very honest that we're flying into the unknown. This is the risk you take with all kinds of exploration.