NASA is keeping Voyager 1 alive by switching off instruments and heaters one by one—but it cannot let the spacecraft become so cold that its fuel lines freeze. If those lines fail, Voyager could lose

With its power fading about four watts a year, Voyager 1 is being kept alive one switched-off instrument at a time, against a hard limit: let it get too cold and the fuel lines that feed its antenna-pointing thrusters could freeze. Nearly half a century after it left Earth, Voyager 1 is being kept alive one switch at a time. Its power supply fades a little every year, so mission engineers at NASA have been turning off instruments and heaters in a careful sequence, trading capab... [5146 chars]