The US Congress on Wednesday bestowed its highest civilian honor on four American space pioneers of the 1960s, marking the first time the Congressional Gold Medal has been awarded to astronauts.

Winners included Neil Armstrong, 81, who was the first man to walk on the Moon; his colleague Buzz Aldrin, 81, who was the second; and Michael Collins, also 81, who was the command module pilot for Apollo 11, the first manned mission to the Moon in 1969.

The fourth was astronaut and former senator John Glenn, 90, the first American to orbit the Earth in 1962.

"We came in peace for all mankind," said Glenn after receiving the award at an hour-long ceremony in the US Capitol Rotunda, complete with fife players, brass band, an honor guard and Norah Jones singing "America the Beautiful."

He then repeated words he'd said to Congress nearly 50 years ago, when addressing lawmakers upon returning from his Earth-orbiting jaunt in the module Friendship 7.

"As our knowledge of the universe in which we live increases, may God grant us the wisdom and guidance to use it wisely."

Democratic House Minority leader Nancy Pelosi hailed the men for their accomplishments in space, calling them "four courageous Americans who represented -- and still do -- the highest hopes of a generation."

Past winners of the Congressional Gold Medal, described as the "highest expression of national appreciation for distinguished achievements and contributions," include Myanmar pro-democracy icon Aung San Suu Kyi, the Dalai Lama, Walt Disney and Pope John Paul II.

The award is rivaled in the United States only by the Presidential Medal of Freedom.

Other aviation and rocket science pioneers have been awarded the medal in the past, including the Wright Brothers, who in 1903 were the first Americans to build an airplane and launch it into flight.

American aviator and inventor Charles Lindbergh won the honor for his 1927 flight from New York to Paris in the single-engine plane known as the Spirit of St. Louis.

And the man known as the father of modern rocketry, physicist Robert Goddard, was awarded the medal in 1959 for his work building the first liquid-fueled rocket.

The award for the four American astronauts was initially approved by Congress in 2009, on the 40th anniversary of the Apollo 11 moon flight which produced the iconic images of spacesuit-clad men bouncing along the Moon's surface, leaving footprints and planting an American flag.

NASA ended its three-decade space shuttle program earlier this year, leaving a gap in human spaceflight and forcing the United States to rely on Russian rockets for rides to the International Space Station until a commercial capsule for low-Earth orbit can be built to take the shuttle's place, perhaps by 2015.

Meanwhile, the US space agency has faced criticism over what some view as a lack of focus.

Armstrong, who has been quite vocal on the matter, appeared on Capitol Hill in September to tell lawmakers the US space program was "embarrassing" and that efforts should be made to return men to the Moon.

While the focus of the ceremony Wednesday was on the past, some speakers spoke hopefully of the future of American spaceflight, with trips to an asteroid and Mars planned for 2025, 2030 and beyond.

"I dare say that in future years, we will be giving this same ceremony and gold medal to the first crew that will land on the planet Mars," said US Senator Bill Nelson from Florida.

NASA administrator Charles Bolden, himself a former astronaut, added: "As we embark upon the next great chapter of human space exploration, we stand on the shoulders of the extraordinary men we recognize today.

"Those of us who have had the privilege to fly in space followed the trail they forged."