Chang'e 2

Overview

Chang'e 2 is a Chinese lunar exploration mission and the second spacecraft in the Chinese Lunar Exploration Program. Launched on October 1, 2010, by the China National Space Administration (CNSA), Chang'e 2 was designed to follow up on the successes of its predecessor, Chang'e 1, by performing high-resolution imaging of the lunar surface and testing technologies for future missions. The mission is named after Chang'e, the Chinese goddess of the Moon.

Mission Objectives

The primary objectives of the Chang'e 2 mission included:

High-resolution imaging of the lunar surface, particularly the Sinus Iridum region, to prepare for the landing of the Chang'e 3 rover.
Testing and validation of key technologies for future lunar missions.
Conducting scientific experiments to enhance our understanding of the Moon's composition and environment.

Spacecraft Design

Chang'e 2 was based on the design of Chang'e 1 but incorporated several improvements. The spacecraft had a mass of approximately 2,480 kilograms and was equipped with a suite of scientific instruments, including:

A high-resolution camera capable of capturing images with a resolution of up to 1 meter.
A laser altimeter to measure the topography of the lunar surface.
A gamma-ray spectrometer to analyze the elemental composition of the lunar surface.
A solar wind ion detector to study the interaction between the solar wind and the Moon.

Launch and Trajectory

Chang'e 2 was launched aboard a Long March 3C rocket from the Xichang Satellite Launch Center. Unlike Chang'e 1, which took a more circuitous route to the Moon, Chang'e 2 used a direct transfer trajectory, reaching lunar orbit in just 112 hours. This direct approach allowed the spacecraft to conserve fuel and extend its operational lifespan.

Lunar Orbit and Operations

Upon reaching the Moon, Chang'e 2 entered an elliptical orbit with a perilune (closest approach) of 100 kilometers and an apolune (farthest distance) of 15 kilometers. The spacecraft then transitioned to a circular orbit at an altitude of 100 kilometers to begin its primary mission phase. During this phase, Chang'e 2 conducted high-resolution imaging of the lunar surface, focusing on the Sinus Iridum region.

Extended Mission

After completing its primary mission objectives, Chang'e 2 embarked on an extended mission to explore other celestial bodies. In April 2012, the spacecraft was directed towards the L2 Lagrange point, a stable point in space approximately 1.5 million kilometers from Earth. Chang'e 2 successfully reached L2 and conducted observations of the solar-terrestrial environment.

In December 2012, Chang'e 2 was redirected towards the asteroid 4179 Toutatis. The spacecraft performed a successful flyby of the asteroid on December 13, 2012, capturing detailed images and data. This marked the first time a Chinese spacecraft had visited an asteroid, demonstrating China's growing capabilities in deep space exploration.

Scientific Contributions

Chang'e 2 made several significant contributions to lunar and planetary science:

High-resolution images of the lunar surface provided valuable data for future lunar missions, including the selection of landing sites for Chang'e 3.
Topographic data from the laser altimeter improved our understanding of the Moon's geological features.
Elemental analysis from the gamma-ray spectrometer enhanced our knowledge of the Moon's composition.
Observations of the solar wind interaction with the Moon contributed to space weather research.

Legacy and Impact

Chang'e 2's successful mission demonstrated China's growing expertise in space exploration and laid the groundwork for subsequent missions in the Chinese Lunar Exploration Program. The mission's achievements in high-resolution lunar imaging, deep space navigation, and asteroid exploration have been recognized as significant milestones in the history of space exploration.