While people throughout the U.S. were enjoying a holiday weekend, NASA scientists were battling an eleventh-hour glitch in the New Horizons mission. The spacecraft, now nine years into its journey, is just days from giving mankind its closest look at Pluto ever. But on July 4, NASA scientists lost contact with the spacecraft for over an hour, due to a timing glitch that overloaded the spacecraft's computer systems. The mission team, working around the clock, has since restored communications and says the July 14 flyby hasn't been endangered by the glitch. New Horizons is expected to begin gathering data once again when its approach sequence begins tomorrow.
Out of Sync
When New Horizons' autopilot detected the glitch, it placed the spacecraft in safe mode, switching controls over to the backup computer. Then, it sent a distress signal of sorts, as well as data to help engineers fix the problem. Engineers immediately stepped into action, forgoing any Independence Day celebrations. The New Horizons team said on Sunday that they'd determined the nature of the error and that it was a “hard-to-detect timing flaw” in a command sequence that occurred as the spacecraft prepared for its up-close Pluto flyby. Engineers were conducting a number of data transfers that apparently overwhelmed the craft's internal computer. But it was familiar territory: New Horizons has entered "safe mode" for various reasons nine times over its more than 3,000-day journey. Working around the clock, the team patched together a fix and beamed it back to New Horizons. “New Horizons is operating flawlessly, it's on course, and all of the instruments in the payload are functioning," Jim Green, NASA's director of Planetary Science said Monday. New Horizons will return to normal science operations on Tuesday, principal investigator Alan Stern said, and its rendezvous with Pluto is still on. Unfortunately, New Horizons won’t be collecting data in the interim, but the temporary hiatus won’t affect any of the primary research objectives of the mission, according to NASA. “These observations from far away aren’t nearly as important as the observations we'll get from within the Pluto system," Stern said in a teleconference Monday. "The weighted loss is far less than 1 percent.”
The Big Approach
Manmade space probes have photographed and studied every planetary body in our solar system except Pluto. But, alas, our journey to this furthest dwarf planet is about to come to an end. On July 14, New Horizons will pass 7,750 miles from the surface of Pluto, which is about 2.9 billion miles away from Earth. Just for perspective, it takes radio signals traveling at the speed of light 4.5 hours to reach New Horizons from Earth. As New Horizons executes its flyby, it will snap plenty of photos of Pluto and its system of moons. These will be used to map their surfaces and get unprecedented insights into their surface composition and atmospheric patterns. New Horizons is certainly one of the blockbuster cosmic events of 2015 – and what's any good blockbuster without its dramatic tension? Follow along with all our updated reporting of New Horizons' progress here.