Learning by resting – in space on Earth

"Crewed spaceflight will continue to be important in the future in order to carry out experiments in microgravity, but we must make it as safe as possible for the astronauts," says Hansjörg Dittus, DLR Executive Board Member for Space Research and Technology. “This bed rest study conducted by DLR, NASA and ESA offers space researchers from all over Europe and the USA the opportunity to work together and jointly acquire as much scientific knowledge about human physiology as possible."

"The DLR Space Administration is using funds provided by the Federal Ministry for Economic Affairs and Energy to finance the experiments by German scientists, all of whom were selected by ESA to participate in the study. Germany's strong participation in the ISS utilisation programme is an excellent framework for German university institutes and research facilities to exploit these unique opportunities – and the findings are relevant to ongoing space research, as well as to terrestrial applications," says Thomas Galinski, the DLR Space Administration Project Director responsible for the study.

The 12 female and 12 male volunteers will spend 60 days in the beds in :envihab, which is part of the DLR Institute of Aerospace Medicine in Cologne. They will remain there for 89 days, including the pre-test and recovery phases. All experiments, meals, and leisure pursuits will take place lying down during the bed-rest phase. The participants will be restricted in their movements, so that the strain on muscles, tendons and the skeletal system is reduced. The beds are angled downwards towards the head end by six degrees. This will simulate the displacement of bodily fluids experienced by astronauts in a microgravity environment.

Leticia Vega, Associate Chief Scientist for International Collaborations for NASA’s Human Research Program, explains: "Both effects are similar to what astronauts experience in space. Although the effects of weightlessness are primarily investigated on the International Space Station, analogues such as :envihab are helpful when studying certain research topics under controlled conditions on Earth. These findings will later be validated on the ISS."

The motto – 'For space and Earth'

"In international collaborations, ESA is planning safe and sustainable long-term missions into the depths of space. To make these missions possible, various risks to the astronaut’s health, and hence to the mission itself, must be minimised," adds Jennifer Ngo-Anh, Team Leader in Human and Robotic Exploration at ESA. "AGBRESA allows us to address the issue of muscular atrophy caused by weightlessness. But other stresses such as cosmic radiation, isolation, spatial restrictions and other issues are on our research agenda as well."

Human physiological research in weightlessness or under simulated conditions is not only important for astronauts to be able to maintain their health and performance in space, but also for people on Earth. Space medicine therefore also encompasses health research for terrestrial applications, in all areas of prevention, diagnostics and treatment.

DLR will provide the premises, the doctors, the support and nutrition team, and the scientists. ":envihab offers the best conditions for this study. We are able to accommodate, care for and study 12 volunteers simultaneously, while also conducting a large number of experiments", says Jens Jordan, Director of the DLR Institute of Aerospace Medicine. "Adjacent to the test facility, we have an MRI system and the DLR short-arm human centrifuge is close by. In a world first, we will be using the centrifuge to test whether, during a long-term bed-rest study, artificial gravity can be used to prevent or counteract the physiological changes experienced in a weightless environment." A large number of experiments will be conducted for this purpose on, among other things, cardiovascular function, balance and muscle strength, accompanied by cognitive tests and invasive examinations such as muscle tissue biopsies, microdialysis, measurement of electrical muscle activity and regular blood sampling.

The human body – a machine that dispenses with things it does not need

The human body is designed for efficiency, which is hardly surprising as its supply of food remained uncertain during many evolutionary stages and conserving strength was important. The result is that the body noticeably reduces all functions and resources that are rarely used – or not used at all – in the medium to long term. The loss of strength and decrease in muscle mass that amateur athletes start to feel after a few weeks without training can reach significant levels among astronauts living in a weightless environment during prolonged space missions. In the absence of gravity, a loss of considerable muscle and bone mass occurs, bodily fluids move into the upper part of the body and the strain on the entire cardiovascular system is reduced, leading to a drop in performance. In short, degeneration in space takes place in fast-forward mode compared with Earth.