How many challenges will astronauts have to overcome to return to the moon?

At the end of February this year, the Japan Aerospace Exploration Agency announced two candidate astronauts, a 46-year-old World Bank risk management expert and a 28-year-old surgeon. They will participate in the US-led "Artemis Project" and strive to achieve the first Japanese landing on the moon. Previously, NASA announced the selection of 28 "Artemis Project" astronauts, including 14 women, echoing the action named after the moon goddess. So, what is special about the new era of manned lunar landing in terms of astronaut selection and training? What new technologies may astronauts use to overcome new challenges?

Japan Aerospace Exploration Agency announces two astronaut candidates

"Return to the Moon" focuses more on people

In 1969, Armstrong's "small step" was a "giant step" for human exploration of the outer planets. After that, the "Apollo Project" sent 12 astronauts to the moon in batches. The goal of the "Artemis Project" is not only to "visit the moon", but its "ambition" and complexity are far greater than its "predecessors".

The plan is to build a space station called "Gateway" in lunar orbit, which can serve as the base camp for the "return to the moon" mission, sending astronauts to the moon from time to time to develop lunar resources, and can serve as an outpost for manned landings on Mars. At the right time, it will send pioneers to Mars to try to build a new home. In contrast, the SLS heavy rocket and the Orion spacecraft, which successfully flew together after more than 10 years of ups and downs, are only the "appetizer" in the entire plan, and the construction of the "Gateway" is the "first course". In more complex systems, the needs and limitations of astronauts must be considered more.

The lunar space station will be jointly built by the United States, Europe, Japan and other parties. The main body consists of core modules such as power and propulsion systems, living and logistics systems, international living modules, as well as functional modules such as refueling modules and airlock modules. It is expected to be able to dock with the Orion spacecraft, "Starship" and cargo supply spacecraft at the same time. After the completion of the space station, it will become the main base for the implementation of the "Artemis Project". The Orion spacecraft and the Japanese White Crane spacecraft will be responsible for replenishing personnel and cargo from the earth to the space station, and the "Starship" will be responsible for sending people and goods from the space station to the moon (and possibly Mars in the long run). This is equivalent to establishing a semi-permanent "post station" in the Earth-Moon space, which is expected to carry out complex lunar missions lasting several months.

Therefore, whether the Gateway can support the long-term stay of multiple astronauts has always been the focus of attention. Not long ago, some aerospace engineers who participated in the design work said that the astronaut living area of ​​the Gateway is too small, making it difficult for astronauts to stand and move around, and most of the space in the cabin is likely to be filled with equipment noise and vibration, which will seriously affect the physical and mental health of astronauts. To eliminate doubts, the project team decided to build a real-size living cabin model to test whether there are hidden dangers that threaten astronauts, so as to launch the first module of the Gateway as planned in 2024.

Schematic diagram of the "Gateway" space station (Source: NASA)

Before the lunar space station is completed, astronauts will also have heavy tasks to do. According to the plan, the third mission of the "Artemis Project" is a manned lunar landing operation. At that time, the astronauts will board the Orion spacecraft, which will be sent to the lunar orbit by the SLS heavy rocket and dock with the lunar module modified from the "Starship" launched in advance. Then, the astronauts will enter the lunar module and land at the South Pole of the Moon.

This time, the astronauts' trip to the moon is expected to be more fulfilling than the "Apollo Project". It may have less excitement and fun of exploration, but it will carry out more detailed and trivial scientific research activities, focusing on finding possible water resources, investigating geological conditions, and laying the foundation for the subsequent establishment of a lunar base.

New challenges are everywhere

Nowadays, more and more ordinary space tourists have visited the International Space Station. Will the new era of manned lunar landing plans included in the space station project relax the physical selection standards for astronauts? The answer may be just the opposite.

It is not difficult to see from the "Artemis Project" that the manned lunar landing plan in the new era has fully absorbed the lessons learned from the long-term operation of the space station.

Humans have never been stationed on an alien planet for a long time. The experience of living in space is generally in sealed facilities in low-Earth orbit, which is significantly different from the environment on the lunar surface. Therefore, astronauts will face many new problems when they stay on the lunar surface for a long time, including physiological adaptability in different gravity environments, radiation hazards and protection, mental health maintenance, and the "blind spots" of space medicine.

The space station is close to zero gravity, while the gravity on the lunar surface is about 1/6 of that on Earth. If astronauts live on the lunar space station and go to the lunar surface to work from time to time, their bodies need to constantly adjust to the gravity environment that is very different from that on the ground. This irregularly changing gravity environment is likely to cause unpredictable damage to the astronauts' cardiovascular system, immune system, nervous system, skeletal muscles, etc.

What's more troublesome is that astronauts work and live in the "lunar circle" for a long time, basically losing the protection of the Earth's magnetic field and being more vulnerable to the threat of cosmic radiation. Physical discomfort is likely to be a common condition, and some serious radiation symptoms are even more worrying.

In fact, the manned lunar mission in the new era is more complicated. It may be the first time that humans have truly carried out long-term activities outside near-Earth space, and the issue of cosmic radiation protection must be addressed. This will also provide more guiding experience for future manned Mars exploration missions.

In addition, astronauts on the moon are far away from the earth's environment, their activities are limited, their interpersonal relationships are simple, and they must always guard against risks such as cosmic radiation, equipment failure, and injuries. For example, the day and night environment on the moon is very different from that on the earth. The day and night alternate for a long time, the temperature difference between day and night can reach 300 degrees Celsius, and there are deserts and dead silence everywhere, which will inevitably affect the astronauts' biological clocks and physical and mental states, causing behavioral and cognitive decline.

Since it takes at least two and a half days to fly back to Earth from the moon, once an astronaut has physical abnormalities and urgently needs emergency treatment, it is impossible to send people back to the ground as quickly as possible or receive emergency support from the ground like on a low-Earth orbit space station. This puts higher demands on the space life support system.

In short, the long-term mission of astronauts in the "lunar circle" will be a greater challenge to their physical and mental quality and the space medical system, and the selection work will only be more rigorous. Considering that the astronauts' lunar scientific research mission is "to a higher level", the standards in the professional field cannot be relaxed either.

More qualified "helpers"

The environment is more unfriendly and the tasks are more arduous, which requires astronauts to have more complete comprehensive qualities.

NASA's selection criteria for Artemis astronauts are: at least 1,000 hours of jet piloting experience or at least three years of work experience in STEM (science, technology, engineering, mathematics) related fields. It is worth mentioning that this is the first time in history that NASA requires astronaut applicants to have a master's degree in a STEM field.

The reason for setting such a high threshold is that NASA believes that compared with low-Earth orbit missions, moon landing and long-term residence in the "lunar circle" require astronauts to have higher physical and mental qualities, creative potential, etc., and astronauts must also pay more attention to teamwork and exert overall effectiveness. In addition, this lunar scientific expedition and experimental mission is not the same as the "Apollo Project", which puts forward special requirements for the professional background and scientific literacy of astronauts.

Starting from 2022, the first batch of astronauts selected for the "Artemis Project" will receive two years of training. Specific projects include operating and maintaining the space station, spacewalks, flying supersonic trainer aircraft, and learning complex robotic operation skills.

After completing basic training, they must undergo special intensive training for the lunar mission. For example, they must improve their endurance and adaptability to the lunar landing and lunar environment, learn to operate lunar spacecraft, and become familiar with flight procedures and missions, not to mention passing the core parts of the mission - lunar landing and lunar surface activity training, lunar residence training, lunar scientific exploration and experimental operation training, etc. Depending on the situation, the training involves individual and group cooperation, or even large-scale joint exercises involving cross-system and full-system participation.

However, thanks to the great development of virtual reality and digital technology, high-quality astronauts will have more "helpers" before landing on the moon in the future. For example, expensive and cumbersome physical and real-life training projects will gradually be eliminated, and astronauts can complete lunar module flight training, space station and lunar surface residence training on a panoramic simulator, and simulated operation assessments involving various scientific surveys and experimental equipment are no problem.

Looking to the future, with the advancement of big data applications and information technology, astronaut selection and training will obtain richer and more diverse data support. Artificial intelligence may participate in mission planning and personnel optimization to ensure the "optimal solution" for selecting astronaut teams for specific flight and scientific research missions. (Author: Li Song)