On July 4th, for about an hour and twenty minutes, my heart stopped. This was the amount of time that New Horizons was quiet. No contact, no data, nothing but the lonely black of space. In this time, the craft did what it was programmed to do. It transferred control to its backup computer, which told the main computer to enter safe mode and suspend all non-essential functions. Then the backup computer attempted to re-establish contact with Earth, 5 Billion Kilometres away.
Contact has been re-established with the craft and its backup computer has been transmitting telemetry data back to mission engineers on Earth in order to determine the problem and move control back to the main computer. Since the shut down, mission engineers have been able to determine the problem and expect mission operations to continue on July 7th, meaning the mission will continue as planned.
So what went wrong? Will it happen again? How can we be sure the mission will be a success?
NASA answered the first two questions in a recent press release. “The 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 flyby. No similar operations are planned for the remainder of the Pluto encounter,” according to a NASA release.
And the answer to the third question, how can we be sure it will be a success? We can never be sure that any mission will be a success. With so many moving parts, such vast distances to cover, and such long missions, we can only do our best to ensure that everything works as well as it can. We can work together and build the best spacecraft we can using the knowledge we have obtained through centuries of scientific innovation.
But we will find out for sure a week from tomorrow.