Astronaut Anil Menon Shows How Weight Is Measured In Space Without Gravity

Measuring body weight in space is different from doing it on Earth because astronauts experience weightlessness. Astronaut Anil Menon recently demonstrated how astronauts measure their mass in space using a special device that works with a spring. 

In his post, Menon explained that the device uses a calibrated spring to measure an astronaut's mass. Unlike a regular weighing machine, it measures how an object moves back and forth when attached to the spring.

In the video, Menon demonstrated how the device works. He explained that astronauts can start the measurement by pressing a button. The spring then moves at a particular frequency depending on the person's mass.

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How do you measure your weight when you are weightless? Watch and you will find out! A spring inside of this unit is calibrated so that a heavy object at the end oscillates at a different frequency than a lighter object. I ended up being 2 kg less than when I arrived. You often lose 10% body mass in the first two weeks and then slowly gain that back though it can vary a lot from person to person.

— Anil Menon (@astro_anil) November 9, 2026

He explained that heavier objects and lighter objects produce different movement frequencies, allowing the device to measure their mass.

Menon also shared details about the changes in body mass that astronauts may experience during their time in space. He wrote, "I ended up being 2 kg less than when I arrived."

He explained that astronauts often lose around 10 per cent of their body mass during the first two weeks in space. They then slowly gain it back, although the amount of change can differ from person to person.