rationalskepticism.org

NASA’s New Horizons spacecraft comes out of hibernation for the last time on Dec. 6. Between now and then, while the Pluto-bound probe enjoys three more weeks of electronic slumber, work on Earth is well under way to prepare the spacecraft for a six-month encounter with the dwarf planet that begins in January.

“New Horizons is healthy and cruising quietly through deep space – nearly three billion miles from home – but its rest is nearly over,” says Alice Bowman, New Horizons mission operations manager at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md. “It’s time for New Horizons to wake up, get to work, and start making history.”

Since launching in January 2006, New Horizons has spent 1,873 days in hibernation – about two-thirds of its flight time – spread over 18 separate hibernation periods from mid-2007 to late 2014 that ranged from 36 days to 202 days long.

In hibernation mode much of the spacecraft is unpowered; the onboard flight computer monitors system health and broadcasts a weekly beacon-status tone back to Earth. On average, operators woke New Horizons just over twice each year to check out critical systems, calibrate instruments, gather science data, rehearse Pluto-encounter activities and perform course corrections when necessary.

New Horizons pioneered routine cruise-flight hibernation for NASA. Not only has hibernation reduced wear and tear on the spacecraft’s electronics, it lowered operations costs and freed up NASA Deep Space Network tracking and communication resources for other missions.
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