Lynn Poole announces that on July 1, 1954, Mars will be closer to the earth than in the past 15 years. He then explains the words Mars, March, and Tuesday originated from Mars, the Roman god of war, and the days of the week were the seven wanderers (or planets in Greek) in the sky. He describes the location of Mars and compares its relative size and distance from other planets using a football field model and the length of an imaginary plane flight. Telescopic views of Mars are unclear and photographs are difficult to make; however, polar caps have been seen and their changing size suggests seasons on the planet. The Dutch astronomer Christian Huyghens sketched Mars with continents and oceans, but his view has been disproved. In 1877 Italian astronomer Schiaparelli noted lines, which he called "canali" or canals, on the surface of Mars. So far oxygen has been undetected on the planet, but a life form such as lichen, a fungus and algae combination, might be possible there.

Lynn Poole describes a diffraction grating as having ridged scales, like a butterfly's wings, that create iridescence. The 75,000 precise ridges must be so accurately spaced that it requires a special machine to make a diffraction grating. Dr. Henry H. Rowland developed the first one in 1860, but Dr. John Strong refined this machine, the ruling engine, in 1950. Using a model of the machine, Dr. Strong explains the operation of a ruling engine, focusing on the perfect twin screws that are its vital parts. The maker of these screws, David Broadhead, of Wellsville, NY, demonstrates how one cuts one of these screws on a machine lathe. In a film, Wilbur Perry, one of the most accomplished mechanical and optical technicians in making diffraction gratings, constructs parts of the ruling engine, including the diamond used to cut the 75,000 grooves on the aluminum-coated glass. Diffraction grating is the basis of spectroscopy, separating light into various colors for analysis.

In this first in a series of programs on space exploration, Dr. John Strong describes the layers of the earth's atmosphere. Heinz Haber discusses the problems that humans must overcome to travel in space. They will need to surmount oxygen deprivation, depressurization, ultraviolet and cosmic radiation, and zero gravity and weightlessness. Protecting man from these elements must be solved before manned space travel can occur.