WASHINGTON (CNN) -- NASA released newly restored videos Thursday of two U.S. astronauts taking the world's first steps on the moon.
NASA hired a digital restoration firm to improve video showing astronauts taking first steps on the moon.
The images were released just four days before the 40th anniversary of the historic event that captivated the world on July 20, 1969.
The release, part of a larger Apollo 11 moonwalk restoration project, features 15 key moments from the historic lunar excursion, NASA said in a statement.
Astronaut Neil Armstrong, now 78, was the first to venture onto the moon's surface after the lunar module Eagle landed on the so-called Sea of Tranquility. Following him was Buzz Aldrin, now 79.
The videos are far superior to the initial dark, fuzzy images people watched on their television sets at the time, although they are far from crisp. Watch a clearer view of "one small step for man" »
The original tapes of images sent back to Earth by Apollo 11 have been lost, and the camera that shot them was left on the moon, according to a NASA official.
Given those circumstances, the team of Apollo-era engineers who helped produce the 1969 live broadcast of the moonwalk acquired the best of the broadcast-format video from a variety of places. These images were turned over to a firm specializing in digitized video restorations, said Mark Hess, chief of public affairs at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
"It was the very best of the broadcast video that we were able to locate from all the sources," he said, referring to any place that had the original broadcast. "The quality of those varied widely."
One source was kinescopes found in film vaults at NASA's Johnson Space Center in Houston that had not been seen for 36 years, NASA said. Kinescopes are the motion-picture records of a television program.
NASA is fairly sure that the original tapes were placed in storage, and taken out and used in the 1970s and 1980s, Hess said.
"Once that technology became irrelevant, they were probably destroyed," Hess said.
These are just the first restored videos to be released, he said. NASA expects that by September, the firm will have worked on the entire moonwalk, and the quality of those videos -- about three hours worth -- will be even better than today's.
The company NASA used, Lowry Digital of Burbank, California, specializes in restoring old Hollywood films and video. iReport.com: Where were you during the moon landing?
The images posted Thursday on the NASA Web site include a two-minute video montage with highlights of the moonwalk, and separate videos of Armstrong and Aldrin descending a ladder to the moon's dusty surface. Each partially restored video is shown beside an original image, for comparison.
Another comparison video shows Armstrong reading a commemorative plaque on the lunar module, which says in part: "Here men from the planet Earth first stepped upon the moon -- July 1969."
The montage video shows highlights from the Apollo 11 mission, from the launch in Florida to the spacecraft's departure from the moon.