New Horizons went into safe mode briefly on Saturday, but the glitch won鈥檛 affect the overall Pluto mission (Image: Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute (JHUAPL/SwRI)
A hiccup in the final days of New Horizons鈥� decade-long journey to Pluto won鈥檛 affect any important science results, NASA says.
Mission controllers are in regular contact with the spacecraft as it nears its final approach on 14 July, but at 5.54 pm GMT last Saturday it suddenly went silent. About 80 minutes later, the NASA tracking station at Tidbinbilla in Australia regained contact with the craft, which had gone into 鈥渟afe mode鈥�, where it stops collecting data.
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鈥淭he spacecraft is in full contact again,鈥� says Glen Nagle, a spokesman for the CSIRO鈥檚 Canberra Deep Space Communication Complex at Tidbinbilla. 鈥淪o it鈥檚 OK. It鈥檚 downlinking data and receiving commands.鈥�
Since it takes 4.5 hours for signals travelling at the speed of light to reach the craft 鈥� making 9 hours in total for the return journey 鈥� resuming normal operations was always going to take time. Later on, NASA revealed the fault wasn鈥檛 a result of software or hardware on board, but rather some commands sent to the craft. 鈥淭he underlying cause of the incident was a hard-to-detect timing flaw in the spacecraft command sequence that occurred during an operation to prepare for the close fly-by,鈥� . 鈥淣o similar operations are planned for the remainder of the Pluto encounter.鈥�
Charon orbiting Pluto (Image: Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute (JHUAPL/SwRI)
Normal operations should resume tomorrow, NASA says.
鈥淚t鈥檚 a good thing it happened now and not on Tuesday next week,鈥� says Nagle, when the Pluto fly-by is due to occur. At the moment, the craft鈥檚 main job is taking increasingly close pictures of the dwarf planet. As a result, a couple of approach images will not have been recorded over the weekend.
The crucial science will be done as the craft passes Pluto, but Nagle says even if the fault had occurred closer to the crucial fly-by moment, data would not have been lost.
鈥淓ven if we stayed out of contact with the craft and re-established contact, say, two weeks from now, the spacecraft still would have done everything it needed to do at encounter time. The command set is on board,鈥� says Nagle. 鈥淚t would take an extraordinary set of circumstances [to make it fail] because each piece of equipment on New Horizons has a backup to keep it going.鈥�
