RENEE MONTAGNE, HOST: Over the weekend, the scientists in charge of an historic mission to Pluto had a heart-stopping moment. They lost contact with their spacecraft just as it neared the dwarf planet. NPR's Geoff Brumfiel picks up the story from there.</s>GEOFF BRUMFIEL, BYLINE: Jim Green is NASA's guy overseeing the Pluto mission. On July 4, he was sitting by his phone.</s>JIM GREEN: I was at home waiting for a call from my son and his wife, who were giving birth to my grandson (laughter).</s>GEOFF BRUMFIEL, BYLINE: But when it rang, it wasn't his son. It was the head scientist from the Pluto mission. The spacecraft had spent almost a decade getting there, and with just a week to go, he told Green they'd lost contact. Green's first thought?</s>JIM GREEN: Something catastrophic could've happened, you know, where it could've hit something.</s>GEOFF BRUMFIEL, BYLINE: Maybe a space rock. Fortunately, around an hour and a half later, the spacecraft got back in touch. Its computers were in safe mode. Here's what happened. The spacecraft was processing photos of Pluto when scientists on Earth told it to start doing something else. The multiple commands overloaded the computers, and they crashed. In other words...</s>JIM GREEN: We had too many windows open.</s>GEOFF BRUMFIEL, BYLINE: Researchers say they've solved the problem. They begin a week of intense observations later today. And as for Green's other big call - well, that came a little later and the news was also good - a healthy baby grandson.</s>JIM GREEN: We cracked open the champagne, and I had two toasts to make.</s>GEOFF BRUMFIEL, BYLINE: Geoff Brumfiel, NPR News.
NASA had a heart-stopping moment over the weekend, when engineers lost contact with a spacecraft they sent to Pluto. A computer crash was behind the problem.