As millions of people watched the lander-ascender combination of China’s Chang’e-5 spacecraft touch down successfully on the moon surface and unfold its solar panels in awe and excitement, researchers from the Space Mechanics Team of Tianjin University cheered with a mixed feeling of relief and pride.
Being part of the efforts to ensure the lunar probe’s successful landing, the research team led by Professor Cui Yuhong and Professor Wang Jianshan has engaged in building ground experimental landing site for test landing on extraterrestrial lunar body.
“We designed and built a simulated moon surface with multiple lunar terrains like rocks, craters and slopes and offered more than 20 terrain combination options,according to technical parameter requirements” said Prof. Cui Yuhong.
On the trial ground, the team then simulated the gravity of the moon, about one-sixth of the gravity on Earth, to test the force and deformation of the lander's soft-landing design.
Senor Engineer Xu Jiafu (in the center) together with team researchers
They developed a 1 / 6G gravity simulation slope that can not only simulate the friction coefficients of various surface obstacles posed by rocks or craters and different landing surfaceson the lunar surface, but also withstand the landing impact of a model weighing several tons, meeting the strict requirements on geometric characteristics, stiffness, elastic modulus and surface friction index of the simulated lunar surface.
Another contribution the team made to the mission was their study about theinteraction between a rocket plume and lunar dusts, which shed light on the design of Chang’e-5 probe’s soft-landing control system.
“The lunar surface was eroded by the exhaust plume and a large amount of lunar dusts are entrained into a high-velocity spray. This high-speed lunar dust can have many adverse effects on the normal operation of the lunar landers like blocking the sights and damaging facilities,” Prof. Wang Jianshan said, “Our research proposes a gas-particle two-way coupled method for simulating the interaction, which proves quite credible after its results were compared with Apollo lander measured data and other simulation results and showed good agreement.”
It is learnt that the Space Mechanics Team of Tianjin University has participated in the national major science and technology projects such as the "lunar exploration project" and the "Mars exploration program" in last decade. Their research methods and achievements have been adopted by the chang'e-3, 4 and 5 landers, and will also be applied to the future Chang'e landers, providing important research methods and reference data for China's lunar exploration project.
By Eva Yin
