The spacecraft's longevity is a testament to innovative engineering, and it has enabled scientists to develop an unprecedented understanding of how the martian landscape and seasons have been changing over time. When Mars Global Surveyor launched on November 7, 1996, it carried with it a limited amount of propellant, and the spacecraft was expected to run out of fuel in April of 2003, ending the capability to steer the ship with small engine thrusters and point the science instruments accurately. In August of 2001, the Mars Global Surveyor team implemented a clever "angular momentum management" strategy that minimized the need for thrusters to help stabilize and balance the spacecraft and kept it on target over viewing areas on the surface of Mars. Part of the angular momentum management scheme tipped the spacecraft at an angle 16 degrees backwards (instead of pointing straight down at the surface), which effectively cut the use of fuel by 800%.