NASA has lost contact with a spacecraft that has orbited Mars for more than a decade.

Maven, an acronym for Mars Atmosphere and Volatile Evolution, abruptly stopped communicating with ground stations on Dec. 6. NASA said this week that it was working fine before it went behind the red planet. When it reappeared, there was only silence.

Launched in 2013 and having entered Mars' orbit in September 2014, Maven began studying the upper Martian atmosphere and its interaction with the solar wind. Scientists ended up blaming the sun for Mars losing most of its atmosphere to space over the eons, turning it from wet and warm to the dry and cold world it is today.

This combination of ultraviolet spectrum images shows atmospheric features of the planet Mars in 2022, left, and the planet's nort

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