In a milestone for space biology, researchers successfully bioprinted the knee joint’s meniscus—the cartilage-like lining that cushions the joint—inside the microgravity environment of the International Space Station. The achievement marks the first time this tissue has been produced in space using a 3D printing process. The effort was reported by Redwire, a company known for its space-enabled biofabrication initiatives.
Central to the experiment was the BioFabrication Facility, a compact 3D printing workstation developed by Redwire and launched to the ISS in 2022. Scientists used human stem cells as living building blocks and collagen as the printing ink, to create a tissue that mimics the native knee meniscus in structure and function. The process demonstrates how microgravity can influence tissue formation, potentially simplifying manufacturing steps that are more challenging under Earth gravity. The team notes that, without heavy weights and with fewer chemical additives required to stabilize constructs, the printed tissues may form and organize more naturally in space.
The mission saw participation from astronauts Frank Rubio, Warren Hoburg, Stephen Bowen, and Sultan Al Nayadi, who supervised and supported the printing process aboard the orbital laboratory. Their hands-on involvement underlines how crewed spaceflight platforms serve as living laboratories for regenerative medicine and biofabrication work that could someday inform medical treatments on Earth and in space alike.
Advocates of space-based biomanufacturing point out that the weightless environment can help maintain the shape and integrity of delicate biological materials during printing. In such conditions, the need for heavy stabilizers or complex fixturing can be reduced, enabling researchers to explore new printing geometries and more intricate cellular architectures. The Redwire project adds to a growing body of work exploring how space may accelerate the development of tissue models for research, drug testing, and therapeutic applications.
Looking ahead, Redwire outlined plans tied to the SpaceX CRS-29 mission, scheduled for November 2023, to continue supplying the ISS with resources to advance pharmaceutical development and regenerative medicine. The company envisions additional bioprinting experiments, including attempts to print cardiac tissue, as part of a broader program to understand how space environments can contribute to biomedical innovation. These efforts are paired with ongoing investigations into how tissue constructs respond to microgravity over longer durations, with implications for both space exploration and medical science on Earth.
Historically, scientists have pursued biocompatible implants and tissue engineering to repair or replace damaged joints. Among notable efforts, early research into knee joint implants emphasized materials that harmonize with human biology and withstand mechanical demands. The current space-driven work complements these terrestrial efforts by offering alternative fabrication pathways and new insights into how cells, scaffolds, and signaling cues interact when gravity is not a stabilizing factor. While the space experiments are still exploratory, they contribute to a broader narrative about enabling personalized, on-demand medical solutions that could one day be produced closer to patients, rather than relying solely on traditional manufacturing routes. The collaboration between space technology developers and life science researchers continues to push the boundaries of what is possible when biology and engineering converge in orbit.