Mary Helen Johnston, American NASA Astronaut

American NASA astronaut Mary Helen Johnston, of the Materials and Processes Laboratory, checks a sample container for a 'Dendrite Remelting and Macrosegregation in Zero-Gravity Casting' experiment at the Marshall Space Flight Center (MSFC) in Huntsville, Alabama, 5th November 1975. The clear vial in the centre of the fixture will contain ammonium chloride kept in a liquid state of above 70 degrees Fahrenheit and will be launched aboard a sounding rocket in December 1975, it is hoped that the experiment will lead to better methods of processing alloys. (Photo by Space Frontiers/Archive Photos/Hulton Archive/Getty Images)