Weight in weightlessness

This image of ESA astronaut Alexander Gerst was shared on his social media channels on 10 September 2018.

Alexander said "How do you weigh yourself in weightlessness? The answer is shaking. When we bounce ourselves at the end of a spring loaded rod, the time it takes for one bounce tells us our exact body mass."

Follow Alexander and the Horizons mission on social media on his website and on his blog.