Apollo 1 tragedy happened during the test,with the Command Module mounted on the Saturn 1B on the launch pad just as in the actual launch, but the rocket was not fueled. At 6:31 pm the crew noticed a fire inside the cabin. Rescuers were short of time to get into the cabin. The crew most likely perished within the first 30 seconds from smoke inhalation or burns. Resuscitation efforts were futile. The accident was caused by large quantity of flammable materials inside the cabin and the oxygen enriched atmosphere.

The crew consists of: Virgil I. "Gus" Grissom, Edward H. White II and astronaut Roger B. Chaffee.