Nestled in an Alpine valley in northwestern Slovenia, the Planica Nordic Centre is not only a place famous for ski jumping but also a scientific hub where researchers study human physiology and medicine in space and extreme environmental conditions.

As secondary school students participating in a University of Ljubljana space science summer school recently visited the centre, the valley was brimming with activity - ski jumpers were training for the coming season and many hikers were getting ready to explore the surrounding trails.

The students' destination was the nearby hotel, Dom Planica, which provides accommodation for world-class athletes but also houses a Jožef Stefan Institute (IJS) laboratory, which has been part of the centre since its opening.

Going from Planica to space

The students were greeted by Igor Mekjavić, a researcher at the IJS Department of Automation, Biocybernetics and Robotics who established the advanced research laboratory.

"The Planica laboratory is home to an international team of researchers who regularly carry out research in sports medicine and human physiology and medicine in space or extreme environments," said Mekjavić, who is considered one of the world's leading experts in environmental and space physiology.

Projections by many space agencies indicate that man will land on the Moon again in the next few years to work and live there for a longer period of time.

However, plans for astronaut missions to Mars are an even bigger step. "Our main task is therefore to study how to best prepare humans for a long stay in space. That is why we are recreating zero-gravity conditions in the laboratory and studying their impact on humans," Mekjavić said while leading the group of students through the research facility.

Horizontal lying down is the standardised way to simulate the weightlessness experienced by astronauts during space exploration, and so volunteers who lie on beds for a number of days play a key role in research at the Planica laboratory.

"We then study how they adapt to a weightless environment, particularly under hypoxic conditions, when the oxygen level in the air is lower than under normal conditions," Mekjavić explained. "These are the conditions that are likely to be present in future spacecraft and habitats on the Moon and Mars."

The oxygen concentration in the air is controlled by simulating altitude conditions. As altitude increases, partial pressure of oxygen in the air decreases. The hotel contains altitude rooms, which at first glance seem like any other standard hotel room, but they are in actually technologically sophisticated rooms where researchers use special equipment to change the conditions.

Like being in a sci-fi movie

This week, they have started a new experiment. "We will simulate a 60-day space mission together with the participants of the study The Effect of Vibration Training during Hypoxic Inactivity."

They will compare and evaluate different training strategies for life in spacecraft, which could prevent the loss of muscle and bone mass and changes in astronauts' cardiovascular system, which are the key health problems they face.

The researchers will also study the participants' sight, which astronauts tend to start losing after spending a lot of time in space. The research results will help not only astronauts but also people on Earth.

"We expect twelve research teams from around the world, mostly Europe, to visit us," Mekjavić said. The study will be done in two stages: the first will run until December 2024, while the second will take place from April to July 2025.

The main research venue will be the IJS Laboratory of Gravitational Physiology, which due to a "human centrifuge" resembles a scene from a science fiction film.

The centrifuge spins on its own axis at extreme speed and can subject participants to strong gravitational forces, same as the ones experienced during rapid acceleration or sudden manoeuvres while in aircraft, on space flights or extreme rides at amusement parks.

Researchers can alter the effect of gravity on the participant and develop training countermeasures to counteract the negative physiological changes that occur in a weightless environment, Mekjavić said.

The laboratory is one of only three institutions where the European Space Agency is researching whether it would be smart to put such a machine in spacecraft and future habitats on the Moon and Mars.

Training new scientists

The centre is dedicated to research but it is also an education hub, a key component in the chain of training new scientists that will mould the future of space missions.

During their visit, the secondary school students, some of whom may be one of these future researchers, learned about a new master's degree programme about human physiology and medicine in space. Called SpaceMed, it will be launched in October.

The six-year study programme is the result of cooperation between the Jožef Stefan International Postgraduate School, University of Caen Normandie and the Charite medical school in Berlin.

After six months in France and six months in Germany, programme participants will come to Slovenia where they will learn how to conduct space medicine tests and research in general.

One of the students present during the tour was Aleš Rus, who recently won a silver medal at the 17th International Olympiad on Astronomy and Astrophysics in Brazil. He was part of the five-member Slovenian team that won two golds and two silvers to rank among the top five teams in the world.