PolyU-made space instruments complete lunar sampling for Chang’e 5

In support of the Nation’s first lunar sample return mission, a research team at The Hong Kong Polytechnic University (PolyU) developed and manufactured one of the key systems for this historic undertaking, namely the “Surface Sampling and Packing System”, in collaboration with the China Academy of Space Technology. The PolyU-developed system accomplished the tasks of automatic sample collection and packaging on the lunar surface following the soft landing of the Chang’e 5 probe on 1 December 2020. The vehicle carrying the samples is currently on course back to Earth, and is expected to touch down in China’s Inner Mongolia region next week.
The collection of lunar samples is a landmark occasion in the history of our Nation’s space exploration programme. It is a great testament to our University’s cutting-edge research capability that PolyU was the only tertiary institution in Hong Kong to contribute to the Chang’e 5 mission.

Dr LAM Tai-fai

Chairman of Council, PolyU

Chang’e-5 is the world’s first lunar-sample return mission in more than 40 years, aiming to bring back a large amount of lunar samples of up to two kilograms via robotic means. The probe adopts two methods of moon surface sampling: one uses a robotic arm for multiple-point surface sample collections, and the other is to drill underground. The team led by Professor YUNG Kai-leung, Sir Sze-yuen Chung Professor in Precision Engineering, Chair Professor of Precision Engineering and Associate Head of Department of Industrial and Systems Engineering, PolyU, was tasked in 2011 to develop the “Surface Sampling and Packing System”, a comprehensive system for lunar surface sampling, packaging and sealing.

Dr LAM Tai-fai, Chairman of Council, PolyU, remarked, “The collection of lunar samples is a landmark occasion in the history of our Nation’s space exploration programme. It is a great testament to our University’s cutting-edge research capability that PolyU was the only tertiary institution in Hong Kong to contribute to the Chang’e 5 mission. Furthermore, the fact that Hong Kong-based scientists at PolyU developed some of the most critical components for the project is a fantastic accomplishment for the whole city, proving that Hong Kong can play an important role in supporting our Nation in making significant strides in the fields of space exploration and science.”

Mr Alfred SIT, Secretary for Innovation and Technology of the HKSAR Government, said, “Over the years, PolyU has actively participated in our Nation’s space exploration projects by developing highly sophisticated space instruments for our country. In the Chang’e 5 lunar exploration project, PolyU fully demonstrated its rich experience accumulated in national and international space projects, its cutting-edge technology as well as its innovative thinking. PolyU’s efforts in research are in line with and complementary to the Government’s goal of developing Hong Kong into an international innovation and technology hub.”

Professor Jin-Guang TENG, PolyU President, said, “The Chang’e 5 lunar mission has been watched closely by the entire world, since it will help the scientific community uncover some of the Moon’s secrets and mysteries. I am immensely proud that PolyU researchers developed the pioneering ‘Surface Sampling and Packing System’ to facilitate the success of this milestone mission. By contributing to such a sophisticated national space project, the University has demonstrated its substantial research competence and commitment to producing breakthrough solutions that push forward the frontiers of technology and science. PolyU will continue to devote itself to the pursuit of research excellence and the creation of innovations that benefit Hong Kong, the Nation and our world.”

Professor Yung expressed the pride he and his team felt to be part of this ground-breaking accomplishment. He said, “Collecting a large amount of lunar samples via robotic means was unprecedented. From research, through design to manufacturing, the development of this system has required a very high level of innovation, precision and reliability. A small glitch anywhere in the complex chain of necessary tasks could have instantly negated all the costly efforts made by those involved in the mission. Thanks to the support of the Nation, the University and the experts at PolyU Industrial Centre, we were able to produce this cutting-edge space-qualified instrument that has successfully acquired samples from the lunar surface. We are indebted to the Nation in entrusting such a critical responsibility to PolyU.”

Consisting of two samplers for collecting loose and sticky forms of lunar regolith, two near-field cameras, as well as a packaging and sealing system, the “Surface Sampling and Packing System” has more than 400 components constructed in different materials including titanium alloy, aluminum alloy and stainless steel, which make the instruments light in weight but at the same time durable and strong enough to withstand the harsh space environment.

Talking about the challenges of the project, Professor Yung said, “As our system needed to operate on the sun-facing side of the Moon where the ground temperatures could be as high as 110 degree Celsius, this innovation had to be highly sophisticated and capable of functioning under extremely high temperatures. It also needed to withstand the extreme space environment during travel to and landing on the Moon which meant enduring impact and shock during lift-offs and landings, high vacuum on the moon, exposure to solar wind and cosmic rays, as well as high-speed re-entry to Earth’s atmosphere.”

“To meet the limited payload requirement, we had to be innovative in our mechanism design and be stringent in weight control. For example, the two samplers are more than a tool to acquire lunar regolith. They are also used to pick up and move the sample container from the lander to the ascender atop,” Professor Yung continued.

Features of the Surface Sampling and Packing System:

Sampler A – Around 35 cm in length, Sampler A, in the shape of a shovel, is specifically engineered for collecting loose regolith. The vibration and impact during the closing of the sampler is an elaborate design to dislodge excessive debris, chisel away large pieces of regolith, tightly enclose the samples and precisely deposit the selected samples into the container without contaminating the surrounding.
Sampler B – Around 30 cm in length, Sampler B is used for collecting sticky samples by coring into the ground with teeth-like metal flaps when opened. It captures the targeted samples through the closing of these metal flaps. The piston inside the sampler pushes the sticky samples into the container during depositing of the sample when the flaps gradually open.
Near-field Cameras – Heat resistant up to 130 degree Celsius, a near-field camera is attached to each sampler. This camera provides a monitoring and vision guidance function to help select scientifically valuable lunar samples. The vision guidance function also enables the sampler to deposit the samples into the container, grip the container and transfer it into the ascender precisely.
Sealing and Packaging System – Weighing 1.5 kilograms, of which the sample container weighs only 360 grams and is used to seal and store the lunar samples for retuning to Earth, this system includes deployment of a funnel to protect the sample container from contamination when the lunar regolith is deposited and a sweeping action to brush away excessive sample to ensure the container lid can be closed properly.
Being the only tertiary institution in Hong Kong that possesses international deep space qualification experience, PolyU has been contributing to the Nation’s space projects since 2010. As part of the Nation’s lunar exploration programme, Professor Yung collaborated with the China Academy of Space Technology to develop a “Camera Pointing System” for Chang’e 3 in 2013 and for Chang’e 4’s historic landing on the lunar far side in 2019, and a Mars Camera for Tianwen 1 in 2020. The “Surface Sampling and Packing System” will be used for the Chang’e 6 mission as well.

PolyU has actively participated in other space exploration projects, designing and manufacturing a number of sophisticated space tools in the past decade. These include the “Mars Rock Corer” for the European Space Agency’s 2003 Mars Express Mission and the “Soil Preparation System” for the Sino-Russian Space Mission in 2011.