The U.S. Navy wanted to boost sailors' night vision so they could spot infrared signal lights during World War II. However, infrared wavelengths are normally beyond the sensitivity of human eyes. Scientists knew vitamin A contained part of a specialized light-sensitive molecule in the eye's receptors, and wondered if an alternate form of vitamin A could promote different light sensitivity in the eye. They fed volunteers supplements made from the livers of walleyed pikes, and the volunteers' vision began changing over several months to extend into the infrared region. Such early success went down the drain after other researchers developed an electronic snooperscope to see infrared, and the human study was abandoned. Other nations also played with vitamin A during World War II - Japan fed its pilots a preparation that boosted vitamin A absorption, and saw their night vision improve by 100 percent in some cases.

 

 

As the United States raced to build its first atomic bombs near the end of World War II, scientists wanted to know more about the hazards of plutonium. Testing began on April 10, 1945 with the injection of plutonium into the victim of a car accident in Oak Ridge, Tenn., to see how quickly the human body rid itself of the radioactive substance. That was just the first of over 400 human radiation experiments. Common studies included seeing the biological effects of radiation with various doses, and testing experimental treatments for cancer. Records of this research became public in 1995, after the U.S. Department of Energy published them.

 

 

Rocket Rider

Before man could launch into orbit and to the moon, he rode rocket sleds on the ground first. NASA scientists developed decompression sleds that could race at speeds of more than 400 mph before screeching to an abrupt halt, and early testing often had fatal results for chimpanzee subjects that suffered brain damage. Starting in 1954, Colonel John Stapp of the U.S. Air Force endured grueling tests that subjected his body to forces 35 times that of gravity, including one record-setting run of 632 miles per hour. As a flight surgeon, he voluntarily took on the risks of 29 sled runs, during which he suffered concussions, cracked ribs, a twice-fractured wrist, lost dental fillings, and burst blood vessels in both eyes.