NASA astronaut Mark Vande Hei arrived at the International Space Station on April 9, 2021, and is expected to return home March 30, 2022, after spending 355 days in low-Earth orbit. This duration breaks the previous record, held by retired NASA astronaut Scott Kelly, by 15 days.

Vande Hei will return in a Soyuz spacecraft as scheduled alongside cosmonauts Pyotr Dubrov and Anton Shkaplerov.

While clocking the single longest spaceflight by a NASA astronaut, Vande Hei contributed to dozens of studies from the hundreds executed during his mission, including six science investigations supported by NASA’s Human Research Program, or HRP.

“Our astronauts are incredible explorers helping expand our knowledge of how humans can live and work in space for longer periods of time,” said NASA Administrator Bill Nelson. “Mark’s record-setting mission and his contributions to science are paving the way for more people to travel to space on longer duration missions as the agency pushes the boundaries of exploration to the Moon and Mars. Thank you for your service, Mark, and congratulations!”

For one investigation, Vande Hei helped grow and evaluate vegetables harvested with the space station’s Vegetable Production System, or Veggie. The investigation seeks to develop a food production system that can help astronauts meet their dietary needs with fresh vegetables cultivated in space.

Vande Hei also provided biological samples for an investigation that collects a core set of measurements, called Spaceflight Standard Measures. The investigation seeks to characterize “normal” changes in the human body during spaceflight. For instance,  wrist-worn sensors that measure activity levels and light exposure can help researchers better understand the sleep-wake cycle of astronauts. Blood and saliva samples collected by crew members throughout their mission can also help scientists assess changes in various hormones, proteins, and cells that reveal how the immune system changes in space.

In addition, he contributed to a separate investigation collecting biological samples from the crew aboard the space station and placing them in a storage bank. Researchers can draw upon the samples to study spaceflight-induced changes in human physiology.

Vande Hei also participated in the first formal investigation into how eating repetitive meals in spaceflight changes the appeal of certain foodsover time. In space, menu fatigue can have serious consequences, including lost appetites, nutritional deficiencies, and loss of body mass. Results will help researchers improve the design of current and future space food systems.

He is also the first astronaut on an extended mission to help researchers investigate whether an enhanced spaceflight diet can allow humans to better adapt to space. Scientists seek answers to questions such as: Could a diet packed with foods rich in nutrients such as flavonoids, lycopene, and omega-3 fatty acids boost immunity and gut microbe function on long journeys into space?

After he lands, Vande Hei will provide additional feedback to researchers investigating potential injuries such as bruises incurred by astronauts from the force of landing. This feedback will help scientists better understand whether long-term human spaceflight makes crew members more susceptible to such injuries. Results will also help NASA design protective measures in future spacecraft.

Vande Hei’s contributions will expand NASA’s knowledge about how the human body adapts to long-term spaceflight as the agency plans for future missions to the Moon and Mars. Until then, taking time to relax and read will help him balance out the rigors of space travel.


NASA’s Human Research Program, or HRP, pursues the best methods and technologies to support safe, productive human space travel. Through science conducted in laboratories, ground-based analogs, and the International Space Station, HRP scrutinizes how spaceflight affects human bodies and behaviors. Such research drives HRP’s quest to innovate ways that keep astron
auts healthy and mission-ready as space travel expands to the Moon, Mars, and beyond.