NASA has developed a new material with the ability to automatically self-seal a bullet hole in just two seconds.
The research has been published in the journal ACS Macro Letters.
The discovery could have a range of applications including repairing spacecraft, ordinary aircraft and ships.
The material is a sandwich of polymer layers with a gel called tributylborane inside. When one of the layers is punctured and the gel is exposed to oxygen it hardens within a second.
NASA was looking for protection for spacecraft and satellites exposed to orbiting junk travelling at 35,000 km/h.