About 10 p.m. Saturday, Champagne bottles were popped and cake cut at the Johns Hopkins Applied Physics Laboratory when scientists received word from a spacecraft 3 billion miles away.
They had successfully brought the New Horizons spacecraft out of hibernation for the last time as it nears the climax of a nearly decade-long journey to observe Pluto close up. Over the first half of 2015, it is expected to get the clearest view man has ever had of the distant dwarf planet.
"We are so very looking forward to turning this very fuzzy little image of a distant planet into something real," said Alan Stern of the Southwest Research Institute, the principal investigator of the New Horizons mission. "Our knowledge of Pluto is like our knowledge of Mars, 50 years ago."
Scientists at the Laurel lab, which NASA tasked with planning and managing the mission, had beamed out timed instructions for the wake-up in August. Right on schedule, New Horizons sent a radio signal indicating it had switched to "active" mode that reached NASA's Deep Space Network station in Canberra, Australia, on Sunday, at 9:53 p.m. Saturday in Eastern time.
They had awoken the spacecraft 17 times before since its 2006 launch, in semiannual checkups and also as New Horizons flew past Jupiter in 2007. But it was nonetheless nerve-racking, said Hal Weaver, New Horizons project scientist at the Hopkins lab.
"Even though we've done it many times, this is the one for the big show," Weaver said.
Everything on the spacecraft appears in good condition and ready to go for observations of Pluto set to begin in January, he said. It will make its closest pass by the planet July 14, at a distance of 7,700 miles.
Scientists know relatively little about Pluto, an object smaller than Earth's moon and more than 15,000 times farther away, even though it has been nearly a century since it was first discovered. Only in recent years have ground-based telescopes been developed that are powerful enough to see it in any detail, though the images are grainy and in low resolution compared to observations of closer heavenly bodies.
New Horizons is scheduled to take its first images of Pluto and the objects orbiting around it Jan. 25, Weaver said. The spacecraft is carrying both a compact multicolor camera and a high-resolution telescopic camera.
By mid-May, New Horizons' view of Pluto is expected to exceed that of the Hubble Space Telescope.
Other observations, using instruments including advanced imaging infrared and ultraviolet spectrometers, two powerful particle spectrometers and a space-dust detector, will begin Jan. 15. The instruments will study the chemical makeup of Pluto's atmosphere and surfaces, map its topography, see how it reacts with the solar wind, and look for rings.
Tribune reporter Deborah Netburn contributed to this article.