Satellites are cool and all, but human spaceflight gets all the attention. One of the problems we’ve known about when humans spend a lot of time in space is that their bones don’t do super well. Bones are made of living material, and they stop growing when not exercised enough — such as when in space. This causes problems on the astronauts’ return to Earth’s gravity.

A new study in the journal Scientific Reports studied seventeen astronauts, male and female, before and twice after going into space. The researchers specifically studied the bone mass and structure of the shin bone (tibia) using an advanced scanning method called high-resolution peripheral computed tomography. Their results showed that astronauts who had been in space for six months or less recovered mass and structure within a year, but astronauts who had been in space for more than six months never recovered back to previous levels.

To be clear both groups did lose bone structure which is one of those features that once lost can never grow back, but the less than six months group rapidly reinforced the remaining structure. The bone loss in the second group was equivalent to aging ten years. Weight lifting could solve this problem, and indeed, astronauts on the International Space Station (ISS) already do this, using a special resistance machine.

The team from the University of Calgary who performed this study is going to expand their research to astronauts who recently returned from a year in space – NASA’s Mark Vande Hei and Roscosmos’s Pyotr Dubrov.

More Information

Space health: The path of most resistance could help limit bone loss during spaceflight (EurekAlert)

Six months in space leads to a decade’s worth of long-term bone loss (Science News)

“Incomplete recovery of bone strength and trabecular microarchitecture at the distal tibia 1 year after return from long duration spaceflight,” Leigh Gabel et al., 2022 June 30, Scientific Reports