NASA has lost contact with a spacecraft that’s been orbiting Mars for more than a decade. Maven abruptly stopped communicating to ground stations over the weekend. NASA said this week that it was working fine before it went behind the red planet. When it appeared again, there was only silence. Launched in 2013, Maven has been studying the upper Martian atmosphere and its interaction with the solar wind since 2014. It also serves as a communication relay for NASA’s two Mars rovers, Curiosity and Perseverance.