China will push ahead with its lunar exploration program despite the United States' decision to suspend its return to the moon, a senior space exploration scientist has said.
// www.chinadaily.com.cn
China Ready For Another Lunar Encounter
Sep 27, 2010
Sydney, Australia (SPX) Sep 27, 2010 - China could launch its second lunar probe within days. The Chang'e 2 spacecraft was originally built as a back-up to China's first lunar orbiter, Chang'e 1, which was launched successfully in 2007. Rather than mothballing the spare spacecraft, China has sensibly planned a follow-up mission that will examine the Moon even more closely than the first.
// www.spacedaily.com
China could launch its second lunar probe
within days.
The Chang'e 2 spacecraft was originally built as a back-up to China's first lunar orbiter, Chang'e 1, which was launched successfully in 2007. Rather than mothballing the spare spacecraft, China has sensibly planned a follow-up mission that will examine the Moon even more closely than the first.
Chinese officials claim that they have greater confidence in their ability to track and navigate the spacecraft, which leads to a faster trip. This is fair enough, but it will also possibly
reduce the exposure of Chang'e 2 to Earth's radiation belts. This could help the longevity of some instruments, but it's probably not a core reason for the change.
Reaching the Moon, Chang'e 2 will be placed in an orbit "100 kilometres closer to the Moon", according to a Xinhua report. The math is simple. Chang'e 1 was placed in an orbit of roughly 200 kilometres, so we can expect
Chang'e 2 to orbit at roughly 100 kilometres above the surface. The orbital altitude has halved!
This means that Chang'e 2 is China's first "close encounter" probe with the Moon.
This is a fairly low orbit that will allow very close studies of the surface. NASA's Lunar Reconnaissance Orbiter (LRO) is currently in a similar orbit.
It was stated that Chang'e 2 will return higher resolution images than its predecessor. It's clear that the camera itself is a better instrument (Chang'e 1's resolution was around 120 metres), but some of the improvements in the images will also be a result of the lower orbit.
Chinese statements speak of resolutions between one metre and seven metres, depending on the distance to the Moon...
It was stated that Chang'e 2 will return higher resolution images than its predecessor. It's clear that the camera itself is a better instrument (Chang'e 1's resolution was around 120 metres), but some of the improvements in the images will also be a result of the lower orbit. Chinese statements speak of resolutions between one metre and seven metres, depending on the distance to the Moon.
It's a fairly large difference, and it suggests a lot of variation in the orbit. It is probable that Chang'e 2 will mostly operate in a near-circular polar orbit, like its predecessor. The spacecraft could be directed into a very low orbit during the final phases of its mission. Some reports have spoken of passes across the surface lower than 10 kilometres, a trajectory that will probably be performed during the final phases of the mission.
What will the spacecraft see?
The resolution won't be as good as LRO, which can see details on other spacecraft that have landed on the Moon. But China will be able to map the Moon with greater precision, and can use its existing global lunar map from Chang'e 1 as a reference framework for the new data...
It is unclear how long the mission of Chang'e 2 will last. Keeping a spacecraft in a lower orbit requires more navigational skill, and also leads to a faster orbital decay. It's possible that this mission will end much sooner than Chang'e 1, but this will be an acceptable compromise for the closer look...
~ В ближайшие дни Китай может отравить к Луне ещё один аппарат - Chang'e 2.
Chang'e 2 будет находится на низкой орбите: 100 км над лунной поверностью (Chang'e 1: 200 км).
Chang'e 2 будет иметь камеру с разрешением от 7 м до 1 м, в зависимости от высоты над поверхностью Луны (разрешение камеры Chang'e 1: 120 м).
Что аппарат сможет рассмотреть?
Его возможности не так хороши как у LRO, который может видеть детали космических аппаратов севших на поверхность Луны, но Китай будет способен создать карту лунной поверности с большой точностью и сможет теперь использовать для этого данные от Chang'e 1.
В настоящее время точно не известно, как долго продлится миссия Chang'e 2.
Чанъэ-2
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