The Apollo 1 fire changed the design of spacecraft
Modifications to spaceships
The fact that the fire happened on earth and not in space made a big difference, as they were able to study the evidence and analyze what had happened on the spacecraft. Thus, they discovered that 100% oxygen environment in the capsule caused the fire to break out quickly. For this reason, NASA redesigned Apollo to fly with 34% oxygen in its pressurized modules.
Also, the engineers carried out many adaptations, modifying the walls of the ship to make them thicker and better withstand increased pressure. They also reduced the amount of flammable material in the crew cabin and checked the flammability of many materials in the capsule.
As a result of the lessons learned, NASA has developed new materials taking into account fire safety. For example, the insulation around cables is made with a special coating so fire resistant that it cannot burn even in a pure oxygen environment.