Chang'e 2

Mission Type: Orbiter

Launch Vehicle: Long March 3C

Launch Site: Xichang, Peoples Republic of China

References: NSSDC Master Catalog: Chang'e 2

1 Oct 2010: Launch

China's second lunar probe, Chang'e-2, ceased orbiting the moon after completing its preliminary missions. It is set to explore outer space travelling 1.5 million kilometers away from the Earth's surface to the L2 Lagrangian point.

Lagrangian points are locations in space where gravitational forces and the orbital motion of a body balance each other. They were discovered in 1772 by the French mathematician Louis Lagrange, who was working on a solution to the "three-body problem". There are five Lagrangian points in the Sun-Earth system, and Chang'e-2 will fly to one nearest Earth.

L2 lies in the Earth's shadow and is exposed to less sun radiation than other Lagrangian points. That makes it an ideal place for scientists to put space telescopes when they want to observe the universe. Several US and European satellites now occupy that spot. China has never tried to send a satellite so far before. Chang'e-2's new mission will pose a big challenge to the country's ability to track and control (satellites) in deep space.

This is the first time scientists have tried to pilot a satellite out of a moon orbit and take it to the L2 point. Previous satellite trips to the point have all started from Earth. The new mission therefore places great pressure on scientists to accurately calculate the point at which the Chang'e-2 must leave its orbit around the moon and make off for the Lagrangian point.

Chang'e-2 entered L2?s orbit in 2011 after spending 77 days traveling away from its previous orbital path around the moon.

Chang'e-2 was launched on Oct 1 this past year. Its chief mission was to test out technology needed to enable an unmanned craft to softland on the moon. China's third lunar probe, Chang'e-3, is to attempt such a landing in 2013. China has a three-stage plan for exploring the moon. Chang'e-2 and Chang'e-3 are part of the second stage, which is to lead to an unmanned moon landing. The third stage is to result in a sample of moon rock being brought back to Earth in 2017.

- CREDIT: NASA