Chang’e 3 – The Third Chinese Robotic Lunar Probe Mission
Chang’e 3 is the third robotic lunar probe mission launched in December 2013.
The primary contractor for the probe was the China Academy of Space Technology (CAST). Chang’e was operated by China National Science Administration (CNSA).
Chang’e 3 was launched as a part of the second phase of the China Lunar Exploration Programme (CLEP).
It was designed to study the lunar surface with the help of the Yutu rover.
This mission made China the third country to soft-land on the Moon’s surface.
The Spacecraft
Chang’e 3 lunar probe consists of two modules:
- The Service Module
- The Lunar Landing Vehicle (着陆器) with a total mass of 3,700~3,800kg
The Lunar Landing Vehicle was China’s first nuclear-powered spacecraft. It was equipped with a radioisotope thermoelectric generator (RTG). The RTG was designed to support the spacecraft operations for 12 lunar months.
The vehicle consisted of:
- A Soft Lander (~1200 kg carrying four scientific instruments)
- A Lunar Rover – Yutu (1.5m tall, ~120kg)
The Mission
The spacecraft was launched onboard the CZ-3B rocket from the Xichang Satellite Launch Centre on 1 December at 17:30 UTC.
The spacecraft was initially parked in a 100km circular lunar orbit. After separating from the Service Module, the Lunar Landing Vehicle descended to a 100x15km elliptical orbit.
At perigee, the LLV fired its thrusters and slowly descended to 100m above the Moon’s surface.
After hovering at this altitude for a while, the vehicle lowered to 4m on a suitable landing site.
On 14 December, the LLV shut off its engines and had a free-fall in northern Mare Imbrium.
Later, a six-wheeled lunar rover Yutu rolled onto the lunar surface.
What Is YUTU?
The Lunar Rover (月球车) designated Yutu (Jade Rabbit) was designed and built by CAST. It was a solar-powered, six-wheeled robotic vehicle. Yutu could propel itself across the lunar surface after landing.
Yutu lost the ability to rove in January 2014. It traveled 114m (377 feet) across the lunar surface. According to Xinhua News Agency, Yutu experienced a mechanical control abnormality. The abnormality occurred due to the complicated lunar surface environment.
Yutu onboard equipment included:
- A radar for detecting the structure beneath the Moon’s surface
- An optical telescope to capture images of the lunar surface
- A mechanical collector to collect lunar soil samples for analysis
Yutu continued to function until mid-2016 while stationary. Although its mission was designed to last for 3 months, Yutu set a new record.
It became the moon rover with the most prolonged operation on the lunar surface.
Did You Know?
Chang’e 3 was launched atop an enhanced variant of the CZ-3B launch vehicle.
The rocket featured six improvements specifically tailored for Chang’e 3 mission, including:
- A dual laser-inertial / GPS guidance system
- Improved orbit insertion accuracy
- Increased launch windows
- A 1,300 kg increase in payload capacity
Chang’e 3 Mission Timeline
November 2009
- SASTIND and CAS approved the concept design of the probe
- The program entered the prototype development stage
November 2011
- The simulated hovering and soft-landing of the Lunar Landing Vehicle succeeded
- The field test of the Lunar Rover succeeded
March 2012
- The prototype development completed
- The development of the flying example commenced
Photo: Pexels.
