Alan LaVern Bean (born March 15, 1932), (CAPT, USN, Ret.)
, is an American former naval officer and Naval Aviator, aeronautical engineer, test pilot, and NASA astronaut; he was the fourth person to walk on the Moon.
 He was selected to become an astronaut by NASA in 1963 as part of Astronaut Group 3.
 He made his first flight into space aboard Apollo 12, the second manned mission to land on the Moon, at the age of thirty-seven years in November 1969.
 He made his second and final flight into space on the Skylab 3 mission in 1973, the second manned mission to the Skylab space station.
 After retiring from the United States Navy in 1975 and NASA in 1981, he pursued his interest in painting, depicting various space-related scenes and documenting his own experiences in space as well as that of his fellow Apollo program astronauts.
Gemini 9A (officially Gemini IX-A) was a 1966 manned spaceflight in NASA's Gemini program.
 It was the 7th manned Gemini flight, the 13th manned American flight and the 23rd spaceflight of all time (includes X-15 flights over 100 km ).
 The original crew for Gemini 9, command pilot Elliot See and pilot Charles Bassett, were killed in a crash on February 28, 1966 while flying a T-38 jet trainer to the McDonnell Aircraft plant in St. Louis, Missouri to inspect their spacecraft.
 The mission was flown June 3–6, 1966 by backup command pilot Thomas P. Stafford and pilot Eugene Cernan.
 The astronauts rendezvoused with the Augmented Target Docking Adaptor, but were unable to dock with it because the nose fairing failed to eject from the docking target due to a launch preparation error.
 Cernan performed a two-hour extravehicular activity, during which he was planned to demonstrate free flight in a self-contained rocket pack, the Astronaut Maneuvering Unit.
 He was unable to accomplish this due to stress, fatigue, and overheating.
Commodore Byron McCandless (September 5, 1881 – May 30, 1967) was a longtime U.S. Navy officer who was awarded the Navy Cross during World War I and the Legion of Merit during World War II.
 He was also prominent in the field of vexillology (the study of flags), and helped design two separate versions of the Flag of the President of the United States.
 He was the father of Bruce McCandless, also a naval officer, and the grandfather of NASA astronaut Bruce McCandless II.
 Commodore McCandless was later promoted to the rank of Rear Admiral on the retired list.
Simplified Aid For EVA Rescue (SAFER) is a small, self-contained, propulsive backpack system (jet pack) worn during spacewalks, to be used in case of emergency only.
 If an untethered astronaut were to lose physical contact with the vessel, it would provide free-flying mobility to return to it.
 It is worn on spacewalks outside the International Space Station (ISS), and was worn on spacewalks outside the Space Shuttle.
 So far, there has not been an emergency in which it was needed.
 SAFER is a small, simplified version of the Manned Maneuvering Unit (MMU), which was used for regular maneuvering.
An astronaut propulsion unit (or astronaut maneuvering unit) is used to move an astronaut relative to the spaceship during a spacewalk.
 The first astronaut propulsion unit was the Hand-Held Maneuvering Unit (HHMU) used on Gemini 4.
Bruce McCandless II (born June 8, 1937), (Capt, USN, Ret.)
, is an American former naval officer and aviator, electrical engineer, and former NASA astronaut.
 During the first of his two Space Shuttle missions he made the first ever untethered free flight using the Manned Maneuvering Unit in 1984.
The Hand-Held Maneuvering Unit (HHMU), also known as the maneuvering gun, or informally as "the zip gun", was used by astronaut Edward H. White in the first American "spacewalk" (extra-vehicular activity, EVA), on Gemini 4, June 3, 1965.
 Different models of HHMU were present on Gemini 4, 8, 10, and 11, but were only used on Gemini 4 and 10.
 It was also used aboard Skylab.
Dr Thomas Anthony "Tom" Lewis, OAM (born 1958) is an Australian author, military historian, editor, teacher, and former naval officer.
 An author since 1989, Lewis worked as a high school teacher, and served as naval officer for 20 years, seeing active service in Baghdad during the Iraq war, and working in East Timor.
Admiral George Anson Byron, 7th Baron Byron (8 March 1789 – 1 March 1868), was a British naval officer, nobleman, peer, politician, and the seventh Baron Byron, in 1824 succeeding his cousin the poet George Gordon Byron, 6th Baron Byron in that peerage.
 As a career naval officer, he was notable for being his predecessor's opposite in temperament and lifestyle.
The Manned Maneuvering Unit (MMU) is an astronaut propulsion unit that was used by NASA on three Space Shuttle missions in 1984.
 The MMU allowed the astronauts to perform untethered EVA spacewalks at a distance from the shuttle.
 The MMU was used in practice to retrieve a pair of faulty communications satellites, Westar VI and Palapa B2.
 Following the third mission the unit was retired from use.
 A smaller successor, the Simplified Aid For EVA Rescue (SAFER), was first flown in 1994, and is intended for emergency use only.

Question: Byron McCandless was the grandfather of what former naval officer who made the first ever untethered free flight using the Manned Maneuvering Unit in 1984?
Answer: Bruce McCandless II