Earlier this week, China took another step towards becoming a major power in space with the launch of the Chang’e-3 lunar probe. On board this vehicle is the Yu Tu (Jade Rabbit) lunar rover, a vehicle that is designed to deploy from the vehicle once it reaches lunar orbit and explore the surface independently. If all continues to go to plan, the Chang’e-3 will reach the Moon by December 14th, and its arrival will certainly be historic.
For starters, the probe’s landing in Sinus Iridum, a basaltic lava plane in the Moon’s northern hemisphere, will be the first spacecraft to make a soft landing on the Moon in 37 years. In addition, it will the be the first time China has landed a spacecraft and a rover on the Moon. This is the latest in the Chang’e program, a series of robotic and human missions that ultimately seeks to put Chinese cosmonauts on the Moon.
The Chang’e-3 mission incorporates two major components – the Lander and the Jade Rabbit rover, which is named after the companion of the Moon goddess Chang’e in Chinese mythology. The three-stage Chang Zheng 3B (Long March 3B) launch vehicle that is being used to send the Chang’e-3 probe to the Moon is roughly a functional equivalent of SpaceX’s Falcon 9 rocket, the heaviest rocket in their fleet.
After launching on Monday from the Xichang Satellite Launch Centre, the rocket was placed into an Earth-Moon transfer orbit and conducted its first separation. Shortly thereafter, its second stage engines were engaged to effect course corrections and bring the lander and rover into lunar orbit. Then came two crucial burns from the third stage engines, which put the Chang’e-3 probe into a parking and then highly elliptical translunar orbit.
Throughout all this, the probe slept, and will continue to do so until it burns its own engines to enter lunar orbit tomorrow.Then will come the tricky bit, landing safely without any input from controllers on Earth. This requires a combination of inertial guidance, extremely precise range and velocity measurements, image recognition, and a pretty fast computer – not to mention a certain amount of luck.
Once landed, the six-wheeled rover will begin exploring the surface and collecting soil samples for analysis. As with other rovers, energy will be provided by a series of solar panels and information obtained during its mission will be sent back to Earth for further analysis. In addition, real-time video and pictures will be captured by the rover’s arsenal of cameras, all of which will be sent back to Earth and shared via Chinese media outlets.
In addition to being a first for China’s space program, the Jade Rabbit also has the added distinction of being outfitted with what is arguably the most sophisticated scientific equipment of any previous rover. Most notable is a powerful ground-penetrating radar capable of penetrating up to 30 meters (100 ft) of lunar soil or about 100 m (330 ft) of lunar crustal material, and analyzing the underlying structure.
The rover is also equipped with an Alpha Particle X-ray Spectrometer (APXS) that uses particle-induced X-ray emission and X-ray fluorescence to determine the abundance of elements within rock and soil samples. The instrument can also find hidden materials, such as water of crystallization, which is otherwise difficult to detect remotely. Finding water on the Moon is an ongoing objective for space agencies, and crucial to plans for future settlement.
Then there is the Lunar Ultraviolet Telescope (LUT), which is designed to act as the first long-term astronomical observatory to ever be placed on the Moon’s surface. The vacuum environment and slow rotation of the lunar environment make an ideal location for near-UV observations that cannot be carried out from beneath the Earth’s obscuring atmosphere.
Another optical instrument is the Extreme Ultraviolet Camera intended to monitor the Earth’s plasmasphere, which is a magnetically active region within the magnetosphere but above the ionosphere. It works by viewing light with a wavelength of 30.5 nm which is scattered from helium ions in the plasmasphere. The lander is also hosting several other cameras and a lunar soil probe.
As already stated, the landing site for Chang’e-3 is in the general area of Sinus Iridum, a northwestern extension to the Mare Imbrium basaltic plane which is surrounded from the northeast to the southwest by the Montes Jura mountain range. A precise location has not yet been announced by Chinese authorities, but it has been widely speculated that it will take place within the vicinity of crater Laplace A – a crater that is about 9 km in diameter.
This is certainly an exciting time, as we are likely to learn plenty of new things about the Moon in the next few weeks! And in the meantime, be sure to check out this animation of the Change’e-3 entire mission- from launch to touchdown and deployment on the Moon, courtesy of
Sources: gizmag.com, nasaspaceflight.com