A new crew recently arrived at the International Space Station (ISS), ready to begin a six-month stint of life in orbit. During its stay, Crew-7 will work on scientific research, including a new suite of experiments into the effects of spaceflight on the human body over time — information that could be crucial to future crewed missions to the Moon and beyond.

The crew consists of NASA astronaut Jasmin Moghbeli, European Space Agency astronaut Andreas Mogensen, Japan Aerospace Exploration Agency astronaut Satoshi Furukawa, and Roscosmos cosmonaut Konstantin Borisov.

The launch had been scheduled for Friday, August 25th, but was delayed by around 24 hours for an extra safety review of the valves in the Dragon’s environmental control and life support system. All the valves were found to be operating as normal, and NASA emphasized that the extra checks were a safety precaution.

With that review complete, the crew was able to launch on Saturday, August 26th, and arrived at the ISS on the morning of Sunday, August 27th, joining four Crew-6 astronauts plus three crew members who traveled on a Russian Soyuz craft.

While on the ISS, the Crew-7 astronauts will work on a variety of experiments, including several into the topic of human health in spaceflight. This includes a new program called Complement of Integrated Protocols for Human Exploration Research on Varying Mission Durations, or CIPHER, a set of 14 different experiments that aim to examine how spaceflight changes the human body based on duration.

The idea of CIPHER is to take data from up to 30 astronauts who spend varying amounts of time on the space station. Researchers collect data from the participants before they launch, during their stay on the station, and once they return to Earth, giving them a view of how the body changes over time.

“A big part of this is understanding the impact of duration on the body as a whole. That’s actually a big knowledge gap for us,” Kristin Fabre, deputy chief scientist for NASA’s Human Research Program, explained to The Verge.

A standard rotation on the ISS is for six months, while some astronauts have done up to a year. But for missions to the Moon and Mars, more information about the longer-term effects of spaceflight on the human body is needed. The research team is hoping to run CIPHER until the end of the ISS, collecting more and more data.

The experiments include taking data on bone strength, eye health, cardiovascular functioning, and muscle atrophy, all of which are known to be affected by time in space.

The ISS is particularly useful for such studies due to its microgravity environment, which is what astronauts would have to deal with on journeys beyond Earth. The Moon has very low gravity, at around one-sixth of the gravity on Earth, and on Mars, the gravity is about one-third of Earth’s. Low gravity causes effects such as fluids pooling in the upper half of the body.

“We think about the International Space Station or low-Earth orbit as a fantastic analog or environment to study microgravity in particular. For CIPHER, we’re really trying to address a very specific hazard for the type of research we’re doing. That’s a very unique thing that the ISS can provide,” Fabre said. 

Some health effects of long-duration space missions can also be modeled using simulations run here on Earth, called terrestrial analogs. NASA’s Crew Health and Performance Exploration Analog, or CHAPEA study, for example, investigates the health effects of factors like limited diet on a crew of volunteers who will spend a year in a simulated Mars environment.

However, other factors in space exploration can’t be modeled, such as radiation exposure and certain psychological aspects of isolation and confinement. So the focus of much human health in spaceflight research is taking what we do know from decades of experience on the ISS and finding ways to apply that to missions beyond low Earth orbit.

For example, muscle loss is a major problem in space, so the ISS currently has an exercise system called ARED, or Advanced Resistive Exercise Device. “And that seems to be really great for bone and muscle health,” Fabre said. “But we’re not going to be able to put that on Orion or on Gateway. So how do we take those learnings and miniaturize them to be more appropriate for these exploration missions?”

The CIPHER experiments will include Crew-7 as participants, though NASA doesn’t share which astronauts will be participating to protect their medical privacy as the data will eventually be made public. The researchers wait until they have data from at least five crew members before sharing information publicly, so data isn’t attributable that way either. 

So it may be several years until CIPHER data is publicly available, but it should help lay the groundwork for keeping humans safe if and when we travel beyond Earth and to other planets.

“We’re really going to need to understand duration and time in space and what that does to the human body before we can make some confident recommendations for crew health for Mars,” Fabre said. “So CIPHER is designed to get us there.”