Context: Virgil Ivan "Gus" Grissom (April 3, 1926  January 27, 1967), (Lt Col, USAF), was one of the original NASA Project Mercury astronauts, a United States Air Force test pilot and a mechanical engineer. He was the second American to fly in space, and the first member of the NASA Astronaut Corps to fly in space twice., The Mercury Seven were the group of seven Mercury astronauts announced by NASA on October 7, 1958. They are also referred to as the Original Seven or Astronaut Group 1. They piloted the manned spaceflights of the Mercury program from May 1961 to May 1963. These seven original American astronauts were Scott Carpenter, Gordon Cooper, John Glenn, Gus Grissom, Wally Schirra, Alan Shepard, and Deke Slayton., An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines., Aeronautics (from the ancient Greek words  "r", which means "air", and  "nautik" which means "navigation", i.e. "navigation into the air") is the science or art involved with the study, design, and manufacturing of air flight capable machines, and the techniques of operating aircraft and rockets within the atmosphere. The British Royal Aeronautical Society identifies the aspects of "aeronautical Art, Science and Engineering" and "the profession of Aeronautics (which expression includes Astronautics)." , Leroy Gordon "Gordo" Cooper Jr. (March 6, 1927  October 4, 2004), (Col, USAF), better known as Gordon Cooper, was an American aerospace engineer, test pilot, United States Air Force pilot, and one of the seven original astronauts in Project Mercury, the first manned space program of the United States., John Herschel Glenn Jr. (July 18, 1921  December 8, 2016) was a United States Marine Corps aviator, engineer, astronaut, and United States Senator from Ohio. In 1962 he was the first American to orbit the Earth, circling it three times. Before joining NASA, Glenn was a distinguished fighter pilot in World War II and Korea with six Distinguished Flying Crosses and eighteen clusters on his Air Medal., World War II (often abbreviated to WWII or WW2), also known as the Second World War, was a global war that lasted from 1939 to 1945, although related conflicts began earlier. It involved the vast majority of the world's nationsincluding all of the great powerseventually forming two opposing military alliances: the Allies and the Axis. It was the most widespread war in history, and directly involved more than 100 million people from over 30 countries. In a state of "total war", the major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, erasing the distinction between civilian and military resources. Marked by mass deaths of civilians, including the Holocaust (in which approximately 11 million people were killed) and the strategic bombing of industrial and population centres (in which approximately one million were killed, and which included the atomic bombings of Hiroshima and Nagasaki), it resulted in an estimated 50 million to 85 million fatalities. These made World War II the deadliest conflict in human history., Aerospace is the human effort in science, engineering and business to fly in the atmosphere of Earth (aeronautics) and surrounding space (astronautics). Aerospace organisations research, design, manufacture, operate, or maintain aircraft and/or spacecraft. Aerospace activity is very diverse, with a multitude of commercial, industrial and military applications., The National Aeronautics and Space Administration (NASA ) is an independent agency of the executive branch of the United States federal government responsible for the civilian space program as well as aeronautics and aerospace research., A test pilot is an aviator who flies new and modified aircraft in specific maneuvers, known as flight test techniques or FTTs, allowing the results to be measured and the design to be evaluated. , Donald Kent Slayton ( March 1 , 1924 -- June 13 , 1993 ) , ( Major , USAF ) , better known as Deke Slayton , was an American World War II pilot , aeronautical engineer , test pilot who was selected as one of the original NASA Mercury Seven astronauts , and became NASA 's first Chief of the Astronaut Office . After joining NASA , Slayton was selected to pilot the second U.S. manned orbital spaceflight , but was grounded in 1962 by atrial fibrillation , an irregular heart rhythm . He then served as NASA 's Director of Flight Crew Operations , making him responsible for crew assignments at NASA from November 1963 until March 1972 . At that time he was granted medical clearance to fly , and was assigned as the docking module pilot of the 1975 Apollo -- Soyuz Test Project , at age 51 becoming the oldest person to fly in space at the time . This record was surpassed in 1983 by 53 - year - old John Young and in 1998 by Slayton 's fellow Project Mercury astronaut John Glenn , who at the age of 77 flew on Space Shuttle mission STS - 95 . Slayton died at the age of 69 on June 13 , 1993 , from a malignant brain tumor ., Strategic bombing is a military strategy used in a total war with the goal of defeating the enemy by destroying its morale or its economic ability to produce and transport materiel to the theatres of military operations, or both. It is a systematically organized and executed attack from the air which can utilize strategic bombers, long- or medium-range missiles, or nuclear-armed fighter-bomber aircraft to attack targets deemed vital to the enemy's war-making capability., Walter Marty "Wally" Schirra Jr. (March 12, 1923  May 3, 2007), (Capt, USN), was an American naval officer and aviator, aeronautical engineer, test pilot, and one of the original seven astronauts chosen for Project Mercury, United States first effort to put humans in space. He flew the six-orbit, nine-hour Mercury-Atlas 8 mission on October 3, 1962, becoming the fifth American, and the ninth human, to ride a rocket into space. In the two-man Gemini program, he achieved the first space rendezvous, station-keeping his Gemini 6A spacecraft within of the sister Gemini 7 spacecraft in December 1965. In October 1968, he commanded Apollo 7, an 11-day low Earth orbit shakedown test of the three-man Apollo Command/Service Module. He was the first person to go into space three times, and the only person to have flown in Mercury, Gemini, and Apollo, logging a total of 295 hours and 15 minutes in space. He retired from the U.S. Navy at the rank of Captain and from NASA after his Apollo flight, becoming a consultant to CBS News for its coverage of the subsequent Apollo flights. He joined Walter Cronkite as co-anchor for the seven Moon landing missions., Hiroshima is perhaps best known as the first city in history to be targeted by a nuclear weapon when the United States Army Air Forces (USAAF) dropped an atomic bomb on the city (and later on Nagasaki) at 8:15 a.m. on August 6, 1945, near the end of World War II., Subject: deke slayton, Relation: military_branch, Options: (A) aircraft (B) army (C) navy (D) united states air force (E) united states army (F) united states marine corps
Output: united states air force