A group of scientists is sending small human organs into space in an attempt to understand aging. This is because a phenomenon has been observed during space travel: the human body can, in a short period, exhibit biological alterations very similar to those that typically appear with advancing age. To investigate this process, researchers sent laboratory-grown models of human brains and hearts to the International Space Station.

The experiments were launched as part of the CRS-35 mission, conducted by SpaceX in October 2026 in collaboration with NASA, the Mount Sinai medical institution, and the company Space Tango. These small organs—known as organoids—are three-dimensional structures created from human cells; while not complete organs, they replicate key characteristics of the tissues found in our bodies.

One of the experiments uses a brain tissue model called "Mibrain," developed from stem cells. It contains neurons, supporting cells, immune cells, and structures resembling blood vessels. Scientists aim to discover how this tissue reacts to microgravity and increased exposure to space radiation. They also intend to investigate whether certain genetic traits make some individuals more vulnerable to changes associated with aging and neurodegenerative diseases.

The second experiment involves small cardiovascular models that exhibit contractions similar to a heartbeat. Up to 16 of these organoids were placed into two specialized devices and installed within an automated laboratory called CubiLab. During the mission, the equipment applies electrical stimuli, conducts pressure tests, records microscopic images, and collects fluid samples; in this way, researchers can monitor how cardiac tissue and blood vessels respond to conditions in space.

In the case of the brain models, NASA plans for approximately five weeks of exposure, followed by comprehensive comparisons with equivalent samples kept on Earth. The goal is to identify which changes are specifically triggered by the space environment and to understand the underlying biological mechanisms. This is crucial because some of the alterations observed in astronauts resemble processes associated with aging, including changes in the cardiovascular system.

If researchers can gain a better understanding of these changes, they might uncover key clues for developing treatments for heart disease and neurodegenerative conditions.