There's a very futuristic reason to explore the Bay of Rainbows, aside from the fact that it's a famous feature of dark patches on the Moon visible from Earth. It's a region of ancient lava flows, from a time when the Moon was full of active volcanoes. Many of these lava flows have left long, deep tunnels beneath the surface of the Moon — just as lava leaves tunnels behind on Earth, too. These lava tunnels are predicted to be regions where humans might start building Moon colonies, because being underground is a good way shield lunar inhabitants from the radiation bombarding the Moon's surface from space.


Ouyang Ziyuan, one of the chief scientists on the Chang'e-3 mission, said in an interview:

The Chang'e 3 mission will achieve three "firsts". Number one: space observation from the moon. This is the dream of many astronomers because atmosphere, wind, snow and pollution don't obstruct visibility as they do on earth. The result is also better because of the longer periods of uninterrupted observation from the moon due to it orbiting the earth. One day of observation on the moon is equivalent to 14 days on earth. Number two: we have an ultraviolet camera on the lander to monitor the earth. This camera is different from the one used by America's Apollo 16. Ours can see the formation of the earth's plasmasphere and its density change. It's better than a satellite, which can only record data section by section as it orbits around the earth. On the moon it can observe half of earth at a time without moving. This is something people have always wanted to do. Number three: we will be the first to learn the structure and layers of the moon 100 meters below its surface with radars installed at the bottom of the rover. As the rover drives on the lunar surface, it will be as it can cut and see what's 100 meters below. These three highlights are what no other countries have done so far.


Yutu will spend three months (about 3 lunar days) exploring a 3-km region, and it has the ability to see 100 meters underground with ground-penetrating radar. This will help scientists understand the structure of the lunar regolith and possibly find lava tunnels that might be good settlement areas. It also has a spectrometer to analyze the chemical composition of the regolith and rocks. Yutu will also be sending high-definition images, including panoramas, back to Earth.

The Chang'e lander has its own, one-year, mission. It has powerful, HD science cameras that can send at a rate of one image per second. Though the lander can't move, it will deploy a powerful telescope which will remain on the Moon, and can see much farther than Earth-based telescopes because there is no atmospheric distortion.


Yutu means Jade Rabbit in Chinese. We can't say how excited we are to see Jade Rabbit hopping across the lunar landscape, taking humanity one step closer to building homes on another world.

Thanks to Jesse B. for the screenshots and research!