Astronauts come home two inches taller from the ISS — What lingers is the real problem

Astronauts can come back from the ISS up to two inches taller because microgravity removes normal spinal compression.

The height gain reflects changes in intervertebral discs and paraspinal muscles, not just a simple stretch.

Some effects of spaceflight, including bone loss and muscle changes, can linger after astronauts return to Earth.

The findings matter for astronaut health and for planning longer missions, including future Mars travel.