Many doctors believe this decline in hormone levels triggers the symptoms of PMS. Changes in brain chemicals or deficiencies in certain vitamins and minerals may also play a role. Too many salty foods, alcohol, or caffeine may make symptoms worse as well.
There have been countless flights made since the invention of the airplane by the Wright Brothers in 1903. It should come as no surprise that the first commercial flight in history occurred in the United States. In fact, it occurred on January 1, 1914, three years before the United States entered the first World War.
Columbia's first flight took place on April 12, 1981. The shuttle program was officially referred to as the Space Transportation System (STS), so this flight was STS-1. The mission had a two-person crew: the commander, John Young, a veteran of Gemini and Apollo, and the pilot, Bob Crippen. The objective was to make sure that Columbia worked well in space.