Human health remains one of the greatest challenges in space exploration.
When astronauts spend long periods in space, their bodies weaken dramatically—especially their muscles and bones.
Now, scientists at ETH Zurich have taken a major step toward solving this problem by successfully 3D-printing human muscle tissue in zero gravity for the first time.
Their work, published in Advanced Science, could pave the way for new ways to study disease and test medicines in space.
To simulate the microgravity of space, the research team led by Parth Chansoria carried out their experiments on parabolic flights—special aircraft that follow an up-and-down flight path, creating brief periods of weightlessness.
During these fleeting moments, the researchers were able to print tiny, realistic pieces of muscle tissue without the interference of Earth’s gravity.
On Earth, printing fine biological structures such as muscle tissue is a delicate and difficult process.
The scientists use a special material called bio-ink, a gel-like substance that contains living cells.
When gravity is present, this mixture can sink or deform before it hardens, causing the 3D-printed structures to collapse or lose their shape. The result is often an uneven, less lifelike model of human tissue.
In microgravity, however, these problems disappear. The bio-ink and cells remain perfectly suspended, allowing scientists to build muscle fibers that are precisely aligned, just like in the human body.
This alignment is critical because realistic models are needed to accurately study how diseases progress or how drugs affect human tissue.
To achieve this breakthrough, the ETH team designed a new 3D bioprinting system known as G-FLight (short for Gravity-independent Filamented Light). This high-speed printer can produce detailed muscle tissue models within seconds.
During their parabolic flight tests, the researchers completed 30 cycles of weightless printing using a specially developed bio-resin, which keeps the cells alive and stable.
The results were impressive: muscle tissue printed in zero gravity showed the same cell health and structure as tissue printed on Earth. Even more promising, the cell-laden bio-resins can be stored for long periods, meaning they could one day be transported to space for experiments aboard the International Space Station (ISS) or future space laboratories.
This achievement marks a crucial step toward tissue engineering in space.
By producing realistic human tissues in orbit, scientists can explore medical questions that are impossible to study on Earth.
For instance, these tissue models could help uncover the causes of muscle atrophy (the muscle loss astronauts experience in space) or allow the testing of new therapies for muscular diseases such as dystrophy.
According to the ETH Zurich team, their success brings us closer to a future where scientists can grow complex human tissues—and perhaps even miniature organs—beyond Earth’s gravity.
In the long run, this technology could transform both space medicine and human health research back on Earth.
