Printing human knee components—in space
You probably didn’t expect our newsletter to go to space. But for this story, that’s exactly where we’re headed.
Redwire Space recently did some history-making bioprinting aboard the International Space Station (ISS). They printed human knee cartilage—a first in space. And they’re not planning on stopping there.
This isn’t just a breakthrough for astronaut patients with knee injuries. It has implications for people back on earth. This is especially true for members of the military, for whom knee injuries are some of the most common orthopedic conditions.
So how does this bioprinting work? And is medtech leaving the planet? Let’s dig in (or blast off).

Bioprinting 101: The knees in space edition
All of this excitement happened in Redwire’s BioFabrication Facility (BFF) onboard the ISS. Four ISS astronauts conducted the experiment: NASA astronauts Frank Rubio, Warren Hoburg, and Stephen Bowen as well as Emirati astronaut Sultan Al-Neyadi.
In the experiment, the BFF printed a knee meniscus using live human cells. The meniscus then underwent a 14-day enculturation process in Redwire’s Advanced Space Experiment Processor. SpaceX’s Crew-6 mission then brought the meniscus back to Earth.
But wait, why did this bioprinting need to happen in space?
On Earth, gravity makes bioprinting tissue challenging. Researchers end up needing to support the printed tissue with scaffolding to keep it from collapsing. With the microgravity conditions on the ISS, there’s no need for that scaffolding.
Of course, this experiment wasn’t just an adventure for the ISS astronauts. It originated as a partnership between Redwire and the Uniformed Services University of the Health Sciences Center for Biotechnology. This institute—specifically, its biomedical research center—searches for new ways to improve military medicine.
Given how commonplace meniscus injuries are for soldiers—and how a meniscus doesn’t require the complicated printing of blood vessels— this experiment seemed like the perfect place to start.
Our perspective: Unexpected medtech players
Redwire’s achievement is an interesting example of a space technology company making a foray into biomedical applications. It’s also not their only biomedical project.
The company’s big ambition is to address the organ shortage by bioprinting human organs in microgravity. Even if they have to start with a meniscus.
This past summer, the company announced its plans to open a 30,000-square-foot research facility in Indiana, focusing on the intersection of biotech and microgravity. And just this month, Redwire stocked the SpaceX commercial resupply mission (SpaceX-29) to the ISS with payloads for a microgravity pharmaceutical drug development project—and a cardiac tissue bioprinting experiment.
With Blue Origin, Boeing, and other spaceflight players developing a private space station, it makes sense that Redwire is also collaborating with Sierra Space to build a space-specific biotech research platform.
We’re looking at this unexpected convergence as a model for how medical innovation may branch out beyond the stars in the future—a future that may be nearer than we think.