Space travel is an unforgiving and exacting science of time and distance with Sir Isaac Newton in the driver’s seat. Missions are calculated down to the minutes and seconds, and critical activities – such as engine burns and EVA activities -- are timed with precision. A mistake in timing is, literally, a matter of life and death. As the United States advanced further into Space, the astronauts needed timepieces that would allow them to time various mission events such as engine burns and EVAs (Extra Vehicular Activity) or commonly called "Spacewalks."