A spacecraft travelling more than 4.6 billion kilometres from Earth has been brought out of “hibernation” as NASA prepares for its planned encounter with Pluto in 2015.

In a statement, NASA confirmed that the New Horizons spacecraft switched from hibernation to “active” mode on Saturday night, bringing the nine-year voyage into a new and highly anticipated phase.

Operating on pre-programmed computer commands, New Horizons is currently 260 million kilometres from Pluto.

NASA reported that it took more than four hours for the radio signal to transmit to the space agency’s Deep Space Network station, located in Canberra, Australia.

New Horizons didn’t wake up to any old alarm clock buzzer. English tenor Russell Watson recorded a special version of “Where My Heart Will Take me,” for New Horizons. The song was also played in mission control after the wake-up was confirmed.

“This is a watershed event that signals the end of New Horizons crossing of vast ocean of space to the very frontier of our solar system, and the beginning of the mission’s primary objective: the exploration of Pluto and its many moons in 2015,” said Alan Stern, the spacecraft’s principal investigator, in a statement.

New Horizons began its voyage in 2006. Since then, the spacecraft has spent approximately two-thirds of its time in hibernation, in an effort to reduce the risk of system failures. Pre-programmed sequences “woke” it up two or three times a year for various maintenance tasks. During hibernation, the spacecraft would send a “beacon-status tone” back to Earth each week.

“Technically, this was routine, since the wake-up was a procedure that we’d done many times before,” project manager Glen Fountain said. “Symbolically, however, this is a big deal. It means the start of our pre-encounter operations.”

Equipped with high-resolution telescopic camera, infrared and ultraviolet spectrometers and other technology, New Horizons is set to begin “observing” Pluto’s system on Jan. 15. Officials say the mission’s closest approach will occur in mid-July.

The spacecraft is the farthest any space mission has ever traveled to reach its target, NASA said.