ESA – Extended space dive

The Vivaldi experiment started its third and final campaign last month at the Medes space clinic in Toulouse, France, with the longest immersion and an additional head-down bed rest study running in parallel with a total of 20 participants.

Vivaldi’s immersion

During Vivaldi III, 10 volunteers lie down in containers similar to bathtubs covered with a waterproof fabric. This keeps them dry and evenly suspended in water.

Submerged to above the torso and keeping arms and head above water, participants experience a sensation of floating without physical support – something close to what astronauts feel while on the International Space Station.

For the whole 10 days, volunteers remain in this position inside the containers filled with water. Participants take part in a wide range of medical experiments and scientific studies to help researchers understand how space affects the human body.

During meals, they use a floating board and a neck pillow. For bathroom breaks, participants are temporarily transferred onto a trolley, maintaining their laid-back position at all times.

The previous two Vivaldi campaigns involved a dry immersion study over five days with women and men volunteering. This latest edition expands the scope, combining a 10-day dry immersion and a 10-day head-down bed rest phase in parallel, each involving 10 male participants.

The two techniques, dry immersion and head-down bed rest, can mimic spaceflight conditions.

“By extending the duration of dry immersion and comparing it to bed rest, we are refining our understanding of how these analogues simulate life in space, the different physiological effects and how they complement each other,” says Ann-Kathrin Vlacil, team leader for enabling science in human exploration at ESA.

Simulating body changes in space, on Earth

In weightlessness, astronauts’ bodies go through a wide array of changes due to lack of gravity – they lose muscle and bone density, the shape of their eye globes can change, and fluids shift to the brain.

Dry immersion takes weight off the body, creating conditions similar to weightlessness, while head-down bed rest mimics the fluid shifts and inactivity experienced in space due to microgravity.

Both methods induce physiological changes affecting the neurological, cardiovascular and metabolic systems.

Researchers are also looking into hormonal changes, immune responses and connections between the nervous and vision systems. 

This space analogue on the ground allows scientists to make hands-on medical assessments and closely monitor body changes in real time.

Down to Earth

Vivaldi campaigns aim to mitigate health risks in astronauts and design better countermeasures for human exploration beyond Earth, but the research could also translate into better healthcare on Earth.

“Bridging the gap between spaceflight and ground-based research is essential for human space exploration. Our findings have significant implications for Earth-based medicine, particularly in ageing-related conditions,” explains Marc-Antoine Custaud, group lead of the ESA bed rest and dry immersion campaigns from the University of Angers, France.

Results may also help design new treatments for patients bedridden for long periods of time, the elderly and those with musculoskeletal conditions.