If you think it's hard waking up after a nine-hour plane flight, imagine doing so after a space voyage of nine years and three billion miles. On Saturday, NASA's New Horizons deep space probe woke itself up from hibernation mode as it began preparations for its flyby of Pluto and its moons next July. Having traveled 2.9 billion miles (4.6 billion km) from Earth and with 162 million miles (260 million km) to go, the signals announcing the awakening took four hours and 26 minutes to cover the distance to NASA’s Deep Space Network station in Canberra, Australia.

Monitored by the New Horizons team at Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, the unmanned spacecraft came out of hibernation automatically due to its preprogrammed instructions on December 6 at 9:53 pm EST and the confirmation signal was sent 90 minutes later.

The US$650 million New Horizons mission was launched January 19, 2006 atop an Atlas V rocket from Cape Canaveral, Florida. The unmanned 1,054 lb (478 kg) nuclear-powered probe was sent on a 9.5-year mission to fly by Pluto and then on to study selected objects in the Kuiper Belt. Sent on a slingshot trajectory using the gravitational pull of Jupiter, New Horizons passed the orbit of Neptune on August 24 and will rendezvous with Pluto on July 14 of next year, which it will pass at a distance of 8,000 mi (13,000 km).

During its passage, it has undergone 18 periods of hibernation ranging from 36 to 202 days in length as a way to conserve onboard resources, limit wear and tear on components, and reduce time on the Deep Space Network. While in hibernation, the spacecraft remained in a powered-down mode while the computers monitored the probe's health and sent back weekly beacon signals to mission control.

Nasa says that over the next few weeks the New Horizons team will carry out systems checks on the spacecraft and write new commands to guide it through the flyby. On January 15, the seven-instrument payload, which includes a compact multicolor camera, a high-resolution telescopic camera will begin observations.

"New Horizons is on a journey to a new class of planets we've never seen, in a place we’ve never been before," says New Horizons Project Scientist Hal Weaver, of APL. "For decades we thought Pluto was this odd little body on the planetary outskirts; now we know it’s really a gateway to an entire region of new worlds in the Kuiper Belt, and New Horizons is going to provide the first close-up look at them."

Source: NASA

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