The Appollo I martyrs are heroes in more ways than one.
One of NASA's responses to the fire was to design a detector for miniscule amounts of smoke particles, to provide an early warning of electrical problems that might lead to a fire - in time to evacuate the capsule if on the ground or hunt down and fix the problem if in space.
The detector used a miniscule amount of radioactive material to ionize the smoke particles and then detected the current conducted by the ions. (Radioactive materials were for NASA, a government agency, to design with, difficult for random inventors or corporations to even consider.)
The first, space-rated, low-volume prototypes were pricey. But the circuitry and the detection chamber were dog-simple and could be dirt-cheap when manufactured in volume.
So this was plowshared, and became the ionization-type smoke detector, the first practical, affordable, smoke detector suitable for broad deployment in residences. Even when this was the only type in use, it was quickly saving, first hundreds, then thousands of lives per year.
Modern detectors, combining ionization and photoelectric mechanisms, are credited with cutting the death toll from fires by somewhere between 1/3 and 1/2. They detect different types of fires, and the one detected by ionization accounts for somewhat less than half of them - which is still an enormous number.
So the loss of those three lives has been repaid with enormous interest in the decades that followed. The benefits are still flowing.