The breakdown of bone mass is one of the greatest challenges during longer stays in space. Without gravity, the body lacks a crucial stimulus – mechanical loading. Bones are, however, living tissue that responds to loading and continuously renews itself. When this stimulus is missing, the balance between bone formation and bone resorption is disrupted. The consequence: the body loses bone mass within a short period of time.

For missions to the Moon or Mars, this is a serious medical risk. The longer people stay in microgravity, the stronger the effects on the musculoskeletal system become: the bones become less load-bearing, and the risk of fractures increases. The question of how bones can remain healthy and regenerate under these extreme conditions is therefore one of the central challenges of space medicine. This is exactly where the research of David Sipos and Sebastian Scholpp in the project “cOSmicStrain” at the Institute of Machine Design and Manufacturing (IDD) in the Department of Mechanical Engineering under the leadership of Professor Andreas Blaeser begins.

Can gravity be replaced?

The TU research team is investigating whether the absence of gravity can be compensated by targeted mechanical stimuli. The focus is on cells responsible for bone formation and regeneration. The central question is: Can bone growth still be stimulated when gravity as a natural stimulus is absent? To investigate this, the researchers are developing experimental systems that allow mechanical influences to be controlled and analyzed in a targeted manner. The goal is to better understand which signals cells need to trigger growth and regeneration – even under conditions that do not exist on Earth.

When engineering meets cell biology

The special approach of the project lies in the combination of engineering sciences and biology. While biological research often observes how cells react to their environment, the team at IDD follows an engineering approach: mechanical conditions are deliberately adjusted to systematically analyze their influence. Methods from materials and process development, fluid mechanics, and biofabrication are used.

Thus, it is possible to investigate how individual cells react to pressure, flow movements, or deformations and what role these stimuli play in bone growth. As a result, biological microprocesses become visible and controllable. Cell growth no longer appears merely as a biological process, but as a process that can be deliberately influenced. This understanding opens new perspectives for the development of intelligent biomaterials and future regenerative therapies.

Research under real space conditions

A decisive framework for the research is the “Cellbox Programme” of the German Aerospace Center at the German Aerospace Center (DLR), supported by the startup company Yuri GmbH. Here, biological experiments are not only simulated in the laboratory, but carried out under real conditions of microgravity. Cell cultures are studied over longer periods aboard the International Space Station (ISS), while comparison experiments take place under artificial Earth gravity.

For the researchers at IDD, this offers a special opportunity: hypotheses from the laboratory can be tested under extreme conditions. Microgravity thus becomes an experimental space in which fundamental biological processes can be observed particularly clearly. The research is part of a larger initiative that deals with the effects of microgravity on biological systems. The goal is to better protect the health of astronauts on future long-term missions and to gain new insights into the adaptability of the human body.