Chang'e 2
Encyclopedia
Chang'e 2 is a Chinese unmanned
lunar probe
that was launched on 1 October 2010. It was a follow-up to the Chang'e 1 lunar probe, which was launched in 2007. Chang'e 2 was part of the first phase of the Chinese Lunar Exploration Program
, and conducted research from a 100-kilometer-high lunar orbit in preparation for a 2013 soft landing by the Chang'e 3
spacecraft. Chang'e 2 was similar in design to Chang'e 1, although it featured some technical improvements, including a more advanced onboard camera with a resolution of one meter. Like its predecessor, the probe was named after a Chinese goddess of the moon
. The total expenditure for the Chang'e 2 mission was approximately CN¥
900 million, or .
After completing its primary objective, the probe left lunar orbit for the L2 Lagrangian point
, to test the Chinese tracking and control network, making the China National Space Administration
the third space agency after NASA and ESA to have visited this point. It entered orbit around L2 on 25 August 2011, and is expected to remain there until the end of 2012.
and Yong-Chun Zheng of the NAOC
, the spacecraft also had a shorter Earth-to-Moon cruise time of 5 days, rather than 12 days. The probe's launch rocket had two more boosters to accomplish this more direct route to the Moon. Furthermore, its laser altimeter's footprint was smaller than Chang'e 1's, achieving 5-meter vertical accuracy in its estimate of the Moon's radius. It also pulsed more frequently - five times per second rather than just once per second, as Chang'e 1's altimetere did. Additionally, the probe's main camera had a spatial resolution of 10 meters, rather than 120 meters.
Late in the mission, Chang'e 2's orbit was lowered to an elliptical one, with the same apolune (100 kilometers) as Chang'e 1, but with a perilune of only 15 kilometers. Tracking for the mission was performed with an X-band radio capability, which was not available for Chang'e 1.
Zheng also remarked that "the mission goals of CE-2 [were] focused into the high resolution image for the future landing site of CE-3 lunar lander and rover. The key technology about soft landing on the Moon will be tested in the CE-2 mission. The success of CE-2 will provide an important technical basis for the successful implementation of China's future lunar exploration."
aboard a Long March 3C
rocket from Xichang Satellite Launch Center
in Xichang
, Sichuan
. The spacecraft entered an orbit with a perigee of 200 kilometers and an apogee of 380,000 kilometers, and separated from the carrier rocket as planned. It was the first time that a Chinese lunar probe directly entered an Earth-Moon transfer orbit without orbiting the Earth first. After the launch, Chang'e 2 arrived in its lunar orbit within 4 days and 16 hours, much faster than the 12 days taken by Chang'e 1. Later, the probe lowered its orbit to 100 km (62.1 mi), with a perilune of 15 km (9.3 mi). Chang'e 2 entered its 100 km working orbit on 9 October 2010 after three successful brakings. On 8 November 2010, China announced the success of all of Chang'e 2's mission objectives, and published lunar surface images with a resolution of up to 1.3 metres (4.3 ft).
, to test the Chinese tracking and control network. The probe reached L2 on 25 August 2011 at 11:27 p.m. Beijing time (14:27 UTC), after a 77-day cruise. It is expected to remain there until the end of 2012. The probe beamed its first batch of data from L2 in September 2011.
on 1 October, in a symbolic celebration of the country's 61st anniversary.
After orbiting the Moon for nearly a year, the probe became the first object to reach the L2 Lagrangian point
directly from lunar orbit, travelling further than any previous Chinese space probe.
Robotic spacecraft
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...
lunar probe
Exploration of the Moon
The physical exploration of the Moon began when Luna 2, a space probe launched by the Soviet Union, made an impact on the surface of the Moon on September 14, 1959. Prior to that the only available means of exploration had been observation. The invention of the optical telescope brought about the...
that was launched on 1 October 2010. It was a follow-up to the Chang'e 1 lunar probe, which was launched in 2007. Chang'e 2 was part of the first phase of the Chinese Lunar Exploration Program
Chinese Lunar Exploration Program
Chinese Lunar Exploration Program , also known as the Chang'e program, is a program of robotic and human missions to the Moon undertaken by the China National Space Administration , the space agency of the People's Republic of China...
, and conducted research from a 100-kilometer-high lunar orbit in preparation for a 2013 soft landing by the Chang'e 3
Chang'e 3
Chang'e 3 is a Chinese lunar exploration mission, incorporating a robotic lander and rover. Scheduled for launch in 2013 as part of the second phase of the Chinese Lunar Exploration Program, it will be China's first lunar rover, and the first spacecraft to make a soft landing on the Moon since the...
spacecraft. Chang'e 2 was similar in design to Chang'e 1, although it featured some technical improvements, including a more advanced onboard camera with a resolution of one meter. Like its predecessor, the probe was named after a Chinese goddess of the moon
Chang'e
Chang'e may refer to:* Chang'e - a traditional Chinese lunar goddess* The Chinese Chang'e space program, part of the Chinese Lunar Exploration Program :** Chang'e 1 - the first CLEP lunar orbiter, launched on 24 October 2007...
. The total expenditure for the Chang'e 2 mission was approximately CN¥
Chinese yuan
The yuan is the base unit of a number of modern Chinese currencies. The yuan is the primary unit of account of the Renminbi.A yuán is also known colloquially as a kuài . One yuán is divided into 10 jiǎo or colloquially máo...
900 million, or .
After completing its primary objective, the probe left lunar orbit for the L2 Lagrangian point
Lagrangian point
The Lagrangian points are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects...
, to test the Chinese tracking and control network, making the China National Space Administration
China National Space Administration
The China National Space Administration is the national space agency of the People's Republic of China responsible for the national space program. It is responsible for planning and development of space activities...
the third space agency after NASA and ESA to have visited this point. It entered orbit around L2 on 25 August 2011, and is expected to remain there until the end of 2012.
Design
Chang'e 2 was broadly similar to the Chang'e 1 mission, but had important differences. While Chang'e 1 operated in a 200-kilometer orbit, Chang'e 2 flew at only 100 kilometers, allowing for higher-resolution images and more precise science data. The probe also possessed a higher-resolution camera, able to resolve features as small as 1 metre across from orbit. According to Qian Huang of the Shanghai Astronomical ObservatoryShanghai Astronomical Observatory
Shanghai Astronomical Observatory , is an astronomical observatory located in Shanghai, China. It has a long history of astrometry, and also operates the Sheshan 25m radio telescope as part of the Chinese VLBI array and the EVN. It was formed in 1962 from the merger of the Xujiahui and Sheshan ...
and Yong-Chun Zheng of the NAOC
NAOC
NAOC may refer to:* Nagano Organizing Committee of the 1998 Winter Olympic Games* National Astronomical Observatory of China* National Airborne Operations Center, the Boeing E-4B aircraft...
, the spacecraft also had a shorter Earth-to-Moon cruise time of 5 days, rather than 12 days. The probe's launch rocket had two more boosters to accomplish this more direct route to the Moon. Furthermore, its laser altimeter's footprint was smaller than Chang'e 1's, achieving 5-meter vertical accuracy in its estimate of the Moon's radius. It also pulsed more frequently - five times per second rather than just once per second, as Chang'e 1's altimetere did. Additionally, the probe's main camera had a spatial resolution of 10 meters, rather than 120 meters.
Late in the mission, Chang'e 2's orbit was lowered to an elliptical one, with the same apolune (100 kilometers) as Chang'e 1, but with a perilune of only 15 kilometers. Tracking for the mission was performed with an X-band radio capability, which was not available for Chang'e 1.
Zheng also remarked that "the mission goals of CE-2 [were] focused into the high resolution image for the future landing site of CE-3 lunar lander and rover. The key technology about soft landing on the Moon will be tested in the CE-2 mission. The success of CE-2 will provide an important technical basis for the successful implementation of China's future lunar exploration."
Mission summary
Chang'e 2 was launched on 1 October 2010 at 10:59:57 UTCCoordinated Universal Time
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...
aboard a Long March 3C
Long March 3C
The Long March 3C , also known as the Chang Zheng 3C, CZ-3C and LM-3C, is a Chinese orbital carrier rocket. It is launched from Launch Complex 2 at the Xichang Satellite Launch Centre. A 3-stage rocket with two strapon liquid rocket boosters, it is a member of the Long March 3 rocket family, and...
rocket from Xichang Satellite Launch Center
Xichang Satellite Launch Center
The Xichang Satellite Launch Center also known as Base 27 , is a People’s Republic of China space vehicle launch facility approximately 64 km northwest of Xichang City, Liangshan Yi Autonomous Prefecture in Sichuan Province....
in Xichang
Xichang
Xichang is a city in and the seat of the Liangshan Yi Autonomous Prefecture, in the south of Sichuan province, People's Republic of China. In 2004 it had a population of 126,700.-Geography:...
, Sichuan
Sichuan
' , known formerly in the West by its postal map spellings of Szechwan or Szechuan is a province in Southwest China with its capital in Chengdu...
. The spacecraft entered an orbit with a perigee of 200 kilometers and an apogee of 380,000 kilometers, and separated from the carrier rocket as planned. It was the first time that a Chinese lunar probe directly entered an Earth-Moon transfer orbit without orbiting the Earth first. After the launch, Chang'e 2 arrived in its lunar orbit within 4 days and 16 hours, much faster than the 12 days taken by Chang'e 1. Later, the probe lowered its orbit to 100 km (62.1 mi), with a perilune of 15 km (9.3 mi). Chang'e 2 entered its 100 km working orbit on 9 October 2010 after three successful brakings. On 8 November 2010, China announced the success of all of Chang'e 2's mission objectives, and published lunar surface images with a resolution of up to 1.3 metres (4.3 ft).
L2 mission
On 8 June 2011, Chang'e-2 completed its extended mission, and left lunar orbit for the L2 Lagrangian pointLagrangian point
The Lagrangian points are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects...
, to test the Chinese tracking and control network. The probe reached L2 on 25 August 2011 at 11:27 p.m. Beijing time (14:27 UTC), after a 77-day cruise. It is expected to remain there until the end of 2012. The probe beamed its first batch of data from L2 in September 2011.
Significance
The launch of the probe coincided with the National Day of the People's Republic of ChinaNational Day of the People's Republic of China
The National Day of the People's Republic of China is celebrated every year on October 1. It is a public holiday in the People's Republic of China to celebrate their national day.The PRC was founded on October 1, 1949 with a ceremony at Tiananmen Square...
on 1 October, in a symbolic celebration of the country's 61st anniversary.
After orbiting the Moon for nearly a year, the probe became the first object to reach the L2 Lagrangian point
Lagrangian point
The Lagrangian points are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects...
directly from lunar orbit, travelling further than any previous Chinese space probe.
See also
- Chinese Lunar Exploration ProgramChinese Lunar Exploration ProgramChinese Lunar Exploration Program , also known as the Chang'e program, is a program of robotic and human missions to the Moon undertaken by the China National Space Administration , the space agency of the People's Republic of China...
- China National Space AdministrationChina National Space AdministrationThe China National Space Administration is the national space agency of the People's Republic of China responsible for the national space program. It is responsible for planning and development of space activities...
- Chang'e 1, Chang'e 2's immediate predecessor, launched in 2007
- Chang'e 3Chang'e 3Chang'e 3 is a Chinese lunar exploration mission, incorporating a robotic lander and rover. Scheduled for launch in 2013 as part of the second phase of the Chinese Lunar Exploration Program, it will be China's first lunar rover, and the first spacecraft to make a soft landing on the Moon since the...
, a robotic lunar lander and rover, planned for launch in 2013 - Exploration of the MoonExploration of the MoonThe physical exploration of the Moon began when Luna 2, a space probe launched by the Soviet Union, made an impact on the surface of the Moon on September 14, 1959. Prior to that the only available means of exploration had been observation. The invention of the optical telescope brought about the...
- Future lunar missions
- Robotic exploration of the MoonRobotic exploration of the Moon-Pioneer program:*Pioneer 0 – failure – orbiter*Pioneer 1 – failure – orbiter*Pioneer 2 – failure – orbiter*Pioneer 3 – failure – flyby...
- 2010 in spaceflight2010 in spaceflightThe year 2010 saw a number of notable events in spaceflight. These included the first test flight of the SpaceX Dragon spacecraft, which is intended to conduct commercial resupply missions to the International Space Station under the Commercial Orbital Transportation Services program, and the...