The Mars Global Surveyor (MGS) was launched in November 1996 and attained Mars orbit in September 1997. In late 2003 it was still in operation, its mission having been extended twice since the nominal end date of January 31, 2001. Mars Global Surveyor was the first successful mission of the National Aeronautics and Space Administration (NASA) to be launched to Mars since Viking in 1976. The only other spacecraft to reach Mars in the intervening decades were the Soviet Phobos 2 in 1989, which lasted only two months in Mars orbit before losing contact with Earth, and NASA's Mars Pathfinder, a lander-rover combination that was launched a month after Mars Global Surveyor but reached Mars 2 months ahead of it, and transmitted data from the planet's surface for 85 days. Mars Global Surveyor was conceived as a low-cost replacement for the Mars Observer spacecraft that was lost in 1993, and carries four of the original six Mars Observer science instruments.