He told the country’s first congressional hearing into UFOs that an analysis by the National Autonomous University of Mexico concluded the remains were about 1,000 years old.
His claims have been greeted with widespread scepticism, including on China’s Zhihu, a platform similar to Quora.
In response to questions from the public, the CASC’s official account – which primarily shares educational content – replied: “As of now, in our space activities we have not found any conclusive evidence of the existence of aliens.”
Other users on the platform expressed doubts about the bodies presented to the Mexican lawmakers, suggesting they were fakes that had been designed to look like a stereotypical alien.
Others pointed out that previous discoveries of this kind have turned out to be the remains of mummified children who had elongated skulls as a result of the practice of having their heads bound in cloth or rope.
Some of Maussan’s critics have pointed to his involvement in presenting these discoveries, while others say he has claimed to have talked to both extraterrestrials and the Virgin Mary.
It also heard from two pilots who said that they had witnessed unidentified flying objects.
Chinese researchers have previously grappled with a mystery experienced by Yang Liwei, the country’s first astronaut, who described hearing knocking sounds while in space.
In his autobiography A Day in Space, Yang described them as “erratic, occurring day and night, without a discernible source from outside or within the spacecraft, resembling a wooden hammer striking an iron barrel”.
Upon returning to Earth, technicians attempted to replicate the mysterious noise but were unsuccessful, despite over a year of experimentation.
“I never heard the sound again. However, the noise re-emerged during [later space flights]. But by then, I recognised it as a normal phenomenon,” Yang wrote.
But scientists finally found an explanation during the 2018 Lunar Palace 1 closed-system survival experiment, when they came across a similar sound and concluded it was probably caused by changes in the spacecraft’s shape due to variations in temperature and pressure.
In March, Zhou Jianping, the chief designer of China’s manned space programme, said encountering aliens could prove beneficial.
“[If we met aliens], our astronauts would try to find a way to communicate with them. Meeting aliens could lead to cooperation beyond our planet, going further than any international partnership we have known,” he said.