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
Timekeeping on Mars 1 (MY1) beginning on the northern spring equinox (L 0) that occurred on April 11, 1955. Although described as "arbitrary", this choice for an initial date of the count results in the great dust storm of 1956 occurring in MY1. This system has been extended by defining Mars Year 0 (MY0) as beginning May 24, 1953, and so allowing for negative year numbers. Long before mission control teams on Earth began scheduling work shifts according to the Martian sol while operating spacecraft on the surface of Mars, it was recognized that humans probably could adapt to this slightly longer diurnal