In the next fifteen years, NASA, the Chinese Space Agency and SpaceX will take a new step in space exploration by sending the first human space missions to Mars. But this plan faces many challenges, including the distance separating us from the Red Planet. Even during opposition, when Mars and Earth are closest to each other, the distance is approximately 55 million kilometers. As a result of using conventional propellant systems, which are chemical rockets, a trip to Mars could take six to nine months, resulting in a mission duration of approximately three years, including operations on the planet’s surface.

Staying in microgravity conditions for such a long time poses a number of problems for the human body, including exposure to solar and cosmic radiation. To solve this problem, NASA is currently working on the possibilities of reducing transit time and developing deep sleep technologies that would allow the crew to sleep for most of the journey. NASA’s NIAC program presented the Study of Torpor in Animals for Space Health in Humans (STASH) project, a deep sleep method developed by experts from California biotechnology firm Fauna Bio Inc.

There are branches of biotechnology that study the characteristics of mammals in order to develop new drugs for human health. One such area is the study of the phenotypes of hibernating mammals and their application in space exploration to reduce risks to crew health. A long stay in space poses special challenges, and studies on the ISS, including NASA’s twin studies, allow us to evaluate the effects of microgravity on the human body. Among the consequences: muscle atrophy, weakening of bone tissue, negative impact on organs, vision, cardiovascular and nervous systems. In addition, the provision of space expeditions will take several months.

The solution to these problems could be for crews to use deep sleep during space travel. This approach will ensure that the crew is healthy and ready for a mission on the planet’s surface when they reach Mars. Developed in collaboration with BioServe Space Technologies at the University of Colorado Boulder, Project STASH is a deep sleep laboratory to be used on the ISS. The experiment involves two rooms where the rodents will be present and the ambient temperature will be reduced to 4 °C to induce deep sleep.

The system will also be equipped with devices that measure the animals’ metabolism in real time, monitoring oxygen consumption, body temperature and heart rate. One of the short-term goals of the STASH project is to study scientific aspects of deep sleep in microgravity, including assessing its ability to protect against muscle and bone loss.

Medium-term missions include testing bioactive molecules that could help space mission crews stay healthy on long journeys. In the future, the deep sleep system could become an important tool for future manned space missions. The system will be equipped with advanced devices that can monitor the animals’ metabolism, oxygen consumption, body temperature and heart rate in real time. Its developers, researchers in the field of deep sleep, set themselves several goals.

The first is a study investigating the scientific basis of deep sleep in microgravity and determining how effectively it protects the body from bone and muscle loss. A longer-term perspective is to test bioactive molecules that can mimic the genetic signatures of deep sleep and evaluate methods of inducing artificial deep sleep. In summary, the team of scientists plans to develop deep sleep technology that can be applied in deep space.

As project leader Kharkiv Sprenger and colleagues note, understanding deep sleep and its potential for spaceflight is incomplete. Currently, there is no infrastructure to conduct deep sleep studies in the space environment, and deep sleep in microgravity conditions has not yet been studied in detail. The STASH project will be the first step on this path, which will form the basis for future research and development of deep sleep systems on long space missions.

Having received funding for the development of the first phase of the project, the team of scientists is preparing to overcome the first hurdles. As project participants note, research conducted using the STASH deep sleep system will be an important first step in obtaining fundamental information about the potential of deep sleep to protect the health of astronauts in space. This information will be useful for the development of drugs and future infrastructure that can support astronauts capable of deep sleep on long-duration interplanetary missions.