Atlas D rocket lifting off with Project FIRE from Pad LC-12.
Fifty years ago, scientists designing the spacecraft for Project Apollo knew that the command module with three astronauts would be slamming into the Earth's atmosphere at over 25,000 mph. To understand the heat stresses on the craft's protective shield, they needed to actually plunge an object with sensors into the atmosphere at that speed and analyze the results. Project FIRE (Flight Investigation Reentry Environment) studied these effects for the various NASA spacecraft. On April 14, 1964, NASA launched an Atlas D rocket carrying a Project Fire test object from LC12 into a 500 mile arc into space. Never intending to reach orbit, the craft separated and plunged down at a steep angle replicating the speed the Apollo capsule would be travelling. Sensors on board the experiment could then measure and define the stresses encountered and the heat effects.
Wind tunnel model of the Project FIRE experiment.
To reach the incredible speed, as the object prepared to return to Earth, and Antares II motor ignited and pushed the experiment even faster. Lasting about 30 seconds, the eventual speed of about 26,000 mph was achieved. While cameras on the ground filmed the fiery descent the craft recorded heat on the exterior at about 20,000 degrees F. After 32 minutes from launch time, the craft impacted into the Atlantic Ocean.