Chinese astronauts plan on conducting a reproductive experiment on the country's new space station using monkeys.
The information was revealed by a scientist involved in the project, reports South China Morning Post.
The experiment will be carried out in Wentian, the largest module of the space station, primarily used for life sciences experiments, said Zhang Lu, a researcher at the Chinese Academy of Sciences in Beijing who is leading the development of supporting equipment for scientific studies on China's Tiangong space station.
Whether monkeys would cooperate remained uncertain, according to a Shanghai-based life scientist who has used them in experiments.
Despite being raised in cages, laboratory monkeys may exhibit negative responses such as decreased activity, hair pulling, or refusal to eat, according to the researcher, who asked to remain anonymous.
The monkeys can become frightened during the rocket trip to the space station.
The scientist further explained that on the ground, a monkey in panic mode might be soothed with toys, music, or even by simply being allowed to interact with other monkeys. The astronauts will face a new task in figuring out how to take care of the monkeys and keep them content and comfortable in space.
The Wentian module has two biological test cabinets which currently have only enough room for algae, fish or snails, but they are expandable and reconfigurable.
Zhang, in a speech posted on social media by the academy on Monday, said some studies involving mice and macaques will be carried out to see how they grow or reproduce in space after studying smaller creatures.
"These experiments will help improve our understanding of an organism's adaptation to microgravity and other space environments."
The challenges of a life sciences experiment in space increased exponentially with the size of the animals used, said Kehkooi Kee, a professor with the school of medicine at Tsinghua University who led an in-orbit stem cell experiment conducted by Chinese astronauts.
However, larger animals, especially the monkeys, shared more similarities with humans.
According to Kee, the astronauts will need to feed them and deal with the waste.
These experiments will be necessary as more nations plan on long-term settlements in orbit around the moon or Mars, he said.
Human breeding in space
Whether humans could breed in space is a question that has been pondered for decades.
In 1992, Jan Davis and Mark Lee, a married couple, were transported to the International Space Station by the United States' Endeavour space shuttle. To the best of NASA's knowledge, no astronauts have engaged in sexual activity in space, though.
Such docking manoeuvres are trickier than most people think, according to Adam Watkins, an associate professor of reproductive and developmental physiology at the University of Nottingham in the United Kingdom, as per SCMP.
First of all, it's challenging to maintain close contact while in zero gravity, Watkins wrote in a letter to Physiology News Magazine in 2020. Second, holding erections and arousal in space is more difficult than it is on Earth as astronauts experience lower blood pressure.
Apart from that, the sheer lack of privacy on shuttles and spacecraft means there are no rooms into which two astronauts can retreat for some time together, he stated.
Harmful effects of cosmic ray exposure
During the Cold War, scientists from the former Soviet Union managed to train a few mice to transcend their physical limitations and engage in intercourse during an 18-day space flight.
Some showed signs of pregnancy, but none gave birth after returning to Earth, reports SCMP.
The researchers suspected that long-term exposure to cosmic rays, which are hundreds of times stronger in orbit than on Earth, could hurt the quality of sperm and eggs.
Some ground experiments suggested that the absence of gravity could damage testicles and some other reproductive organs, leading to a significant decline in the sex hormone levels of test animals.
But other studies produced more positive results.
Long-term health monitoring data collected on the ISS found that testosterone levels dropped near a launch or return mission, but the readings remained normal most of the time the astronauts were in orbit.
A Nasa experiment on the ISS found that gravity changes and radiation had little impact on human sperm.
China is currently the only nation operating its own space station.
Mengtian, the last major module, docked with the main structure of the station on Tuesday, paving the way for the full operation of the facility before the end of this year.
The Chinese space station can host up to six astronauts in private quarters.
Tiangong, which means heavenly palace, is expected to be the largest human outpost in near-Earth orbit after the retirement of the ISS in the next few years.