Lander (spacecraft) a landing which should have come on 25 December 2003 was not received. Indeed, no communication was ever established and "Beagle 2" was declared lost on 6 February 2004. The proposed 2009 British Beagle 3 lander mission to search for life, past or present was not adopted. The French/ESA NetLander mission for 2007 or 2009, with an orbiter and 4 landers, was cancelled because it was too expensive. Its successor, Mars MetNet, a multi-lander mission for 2011–2019 was not adopted by the ESA. The American Mars Exploration Rovers "Spirit" and "Opportunity" were launched in June and July 2003. They reached
Sol (day on Mars) 39 minutes and 35.244 seconds. The sidereal rotational period of Mars—its rotation compared to the fixed stars—is only 24 hours, 37 minutes and 22.66 seconds. The solar day lasts slightly longer because of its orbit around the sun which requires it to turn slightly further on its axis. When a spacecraft lander begins operations on Mars, the passing Martian days (sols) are tracked using a simple numerical count. The two Viking missions, Mars Phoenix and the Mars Science Laboratory rover "Curiosity" count the sol on which each lander touched down as "Sol 0", as will the InSight mission. Mars Pathfinder