Ground control teams lost radio contact with New Horizons for about 80 minutes on Saturday when the spacecraft put itself in an automated safe mode after it switched over from its primary to its backup computer. What triggered the computer switch is under investigation.
With New Horizons about 3 billion miles from Earth, radio signals traveling at the speed of light take about 4.5 hours to arrive and another 4.5 hours to get the spacecraft’s return messages.
“Full recovery is expected to take from one to several days,” NASA wrote in a status report on Saturday. “New Horizons will be temporarily unable to collect science data during that time.”
On Sunday, ground controllers planned to relay a final batch of instructions to New Horizons to prepare for its July 14 flyby of Pluto, the only major body in the solar system that has not yet been visited by a robotic spacecraft.
The “encounter program” includes software to prohibit the very type of automated safe mode that New Horizons executed Saturday afternoon.
“Encounter mode short-circuits the on board intelligent autopilot so that if something goes wrong, instead of calling home for help, which is what most spacecraft do and what New Horizons does during cruise flight, it will just stay on the timeline. It will try to fix the problem, but it will rejoin the timeline because if it ‘went fetal,’ as we say, if it just called home for help, it could miss the flyby,” New Horizons lead scientist Alan Stern told Discovery News before Saturday’s problem.
Read more at Discovery News
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