"Our thoughts and prayers go out to Bruce's family," acting NASA Administrator Robert Lightfoot said in a statement on McCandless, who died Dec. 21 at the Los Angeles County University of Southern California Medical Center. The cause of death was not immediately disclosed.
"He will always be known for his iconic photo flying the MMU," Lightfoot said of McCandless' 1984 ride into the cosmic void from the Space Shuttle Challenger using a Manned Maneuvering Unit -- the NASA jetpack.
McCandless, a naval aviator who flew missions off the aircraft carrier USS Enterprise during the Cuban missile crisis, had a remarkable Navy heritage.
His father, the late Rear Adm. Bruce McCandless, received what was then known as the Congressional Medal of Honor for his actions on Dec. 12-13, 1942, in the Battle of Savo Island near Guadalcanal in the Pacific in World War II.
Rear Adm. McCandless, then a communications officer aboard the New Orleans-class cruiser USS San Francisco, was knocked unconscious by shell fire from superior forces of the Imperial Japanese Fleet that killed or wounded his commanders on the bridge.
When he came to, McCandless took charge.
He "boldly continued to engage the enemy and to lead our column of following vessels to a great victory," his medal citation said.
McCandless paternal grandfather, Commodore [later Rear Admiral] Byron McCandless received the Navy Cross in World War I, and his maternal grandfather, Navy Capt. Willis Winter Bradley was the first recipient of the Congressional Medal of Honor in World War I, NASA said.
On July 23, 1917, aboard the cruiser USS Pittsburgh, then-Lt. Bradley was blown back by an accidental gunpowder explosion. Bradley recovered, crawled into the burning compartment and put out the flames that threatened to set off more powder explosions and possibly sink the ship.
Rear Adm. Bruce McCandless, Byron McCandless and Willis Winter Bradley were all graduates of the U.S. Naval Academy, as was astronaut Bruce McCandless, who was a classmate of Sen. John McCain, chairman of the Senate Armed Services Committee.
In a statement on McCandless' passing, McCain called him "a brilliant aviator and astronaut who dedicated his life to serving the country he loved. Bruce and I were both members of the Class of 1958 at the United States Naval Academy."
"As an undistinguished graduate of that class, I always looked up to Bruce -- not only for his incredible intellect, but also for his character and integrity, which embodied the highest values of the United States Navy," McCain said.
"Bruce is perhaps best known for carrying out the first untethered spacewalk," McCain said. "The iconic photo of Bruce soaring effortlessly in space has inspired generations of Americans to believe that there is no limit to the human potential."
Before he made the untethered Extravehicular Activity, or EVA, as a mission specialist aboard Challenger, McCandless had been a mission control capsule communicator [CAPCOM] for the Apollo 11 landing on the Moon in 1969.
McCandless later said in the back of his mind as he ventured out on Feb. 8, 1984, from Challenger was the historic quote from Neil Armstrong as he stepped onto the Moon: "That's one small step for a man, one giant leap for mankind."
"I wanted to say something similar to Neil when he landed on the moon, so I said, 'It may have been a small step for Neil but it's a heckuva' big leap for me,'" McCandless said. "That loosened the tension a bit" for those involved in the mission, he said.
In a 2006 interview with the Daily Camera of Boulder, Colorado, McCandless played down his accomplishment.
"I was grossly overtrained," he said. "I was just anxious to get out there and fly. I was very comfortable" but "it got so cold my teeth were chattering and I was shivering, but that was a very minor thing."
McCandless traveled more than 300 feet from the shuttle, and the photo of him in his white NASA suit in the blackness of space with the blue planet Earth as a backdrop became a sensation.
Aboard the shuttle Discovery in 1990, McCandless was part of the crew that launched the Hubble Space Telescope.
All told, McCandless logged more than 312 hours in space, including four hours of spacewalks. After leaving NASA, he worked for Lockheed Martin Corp.'s Space Systems division in Colorado.
Services for McCandless have been planned for Jan. 16 at the Naval Academy's Main Chapel in Annapolis, Maryland, followed by burial at the Naval Academy Cemetery.
-- Richard Sisk can be reached at Richard.Sisk@Military.com.