You've seen Apollo 13. You can recite The Right Stuff from memory. There isn't a Discovery Channel documentary you haven't devoured.
What does a space addict do next?
For many, there's only one person they can count on for a fix: a former TV station manager turned full-time NASA film sleuth named Mark Gray.
Gray spends his days doggedly tracking down rare and little-seen government film from the golden age of the U.S. space program - the first manned Mercury missions through the early days of the space shuttle.
After some digital cleaning and light editing, he packages the images onto DVD and sells them through his two-man company, Spacecraft Films.
Although Gray says you would never know it from Hollywood productions and cable documentaries - which tend to recycle the same tired clips - NASA and its contractors amassed a vast trove of celluloid over the years.
"They had cameras everywhere," Gray says. Since he started the company in 2001, he estimates he's pored over a quarter-million feet of 16 mm film and video, some of it largely untouched and unwatched.
"There'll be times when you open up a can and it looks like it's been taped up since 1965," he says.
Some of Gray's finds are moments only an engineer could love: Neil Armstrong practicing his historic moonwalk at the bottom of a NASA swimming pool, or technicians re-creating the near-disastrous explosion aboard Apollo 13.
One of Gray's favorite "gems," as he calls any obscure find, is film from a camera mounted inside the Saturn V rocket's fuel tank. Shot for engineering purposes, it shows sloshing liquid oxygen propellant being slurped down by the rocket's engines.
Nerdy? You bet, says Dwayne Day, 38 of Vienna, Va., who counts the fuel-tank shot among his favorites. But Day says that's the reason he and others buy Gray's DVDs in the first place.
"It takes you to places that nobody, not even NASA personnel, were allowed to go," he says. "I always wondered what liquid oxygen looks like."
Other images that Gray has turned up over the years have more universal appeal.
Almost everyone, for example, has seen the TV clip of a fuzzy Armstrong hopping onto the moon for the first time. But Gray's Apollo 11 DVD set includes a rarer gem: 16 mm color film of the event shot from the window of the Apollo 11 lunar module.
The footage - which was only developed after the crew's return and thus not widely circulated - is sharp enough to make out Armstrong's face.
"Mark has done a tremendous service to history," says Andrew Chaiken, whose book, A Man on the Moon, is one of the definitive chronicles of the Apollo years. "A lot of this stuff is not readily available."
Still, Gray concedes that his products aren't for everyone. His Apollo 17 set, for example, spans six DVDs and runs 23 hours. The first several are devoted just to the oh-so-slow rollout of the Saturn V rocket onto the launch pad.
"If you're not interested in it, you're going to find a lot of it boring," Gray says.
Dwight Boniecki, a broadcast engineer in Cologne, Germany, who owns most of the sets, says he fast-forwards through the tedious bits, or puts his DVDs on while he's having dinner or surfing the Internet.
"I shouldn't tell you all this because you'll say, 'No wonder this man has no girlfriend,'" says Boniecki, 37, who was so inspired by the 1960s-era footage that he's started writing a book about the history of Apollo television cameras.
But the DVDs are more than a treasure chest of nostalgia for baby boomers and hardcore collectors.
Gray says he recently received inquiries from young engineers working on Orion, NASA's next-generation moon-bound spacecraft.
The engineers were designing a launch escape system, Gray says, and were interested in one of his most popular DVD sets: a collection of rocket explosions.
Scholars have also turned to Gray for help. Auburn University historian James Hanson used the Apollo 11 set while writing his 2005 biography of Armstrong.
"I watched it late at night in bed with all the lights out," Hanson says. "It really put me in the mood for what I had to do with that part of the book."
Gray has even heard from several Apollo-era astronauts, who ordered sets for themselves or their grandchildren. One firm rule: Astronauts don't pay. "They shot a lot of this stuff, after all," Gray says.
Gray grew up in Huntsville, Ala., a few miles from the facility where the Saturn V moon rocket was developed. His father was an engineer on the project, and Gray, now 44, says he could see the F-1 engine test stands from his house.
"I remember them shaking the ground. You could see the smoke," he says.
He spent most of his adult career in local television, eventually rising to station manager. But just shy of his 40th birthday, his position was eliminated.
"I came to the conclusion that I wanted to do more than make sure there was a station for Jerry Springer to be on," he says. So he cashed in his retirement account and decided to turn his passion for space into a business.
Despite its niche status, Gray has done surprisingly well. The company, he says, broke even its first year and has sold more than 170,000 DVD sets to date. The sets cost $20 to $80.
Still, it's tough work. Although much of the early NASA film and videotape is collected at the National Archives facility in College Park, other reels are scattered in government vaults throughout the country.
Gray spends much of his time scouring old aerospace company progress reports, yellowing NASA memos and other obscure documents for clues to the whereabouts of obscure footage.
He also spends a lot of time waiting. At the National Archives, Apollo-era color film is stored in freezers and takes a day to thaw out before Gray can view it. Black-and-white footage is stored in an offsite, underground vault, he says.
Gray says his customers tend to be as fanatical about space as he is and frequently call or send e-mail for updates on new video sets. "These people hound me," he says.
Responding to that demand, Gray is working on new sets on Skylab (NASA's first space station) and the historic Apollo-Soyuz Test Project. That 1975 flight was the final Apollo mission and the first joint venture between U.S. and Soviet astronauts.
But Gray's regular customers have also learned to be patient, knowing his desire to turn up unique footage often borders on obsessive.
This month, for example, Gray was supposed to release a DVD set on the X-15, a sleek rocket plane developed in the late 1950s by NASA and the Air Force.
But now he's not sure he'll make it. Last week, Gray decided to fly to College Park to follow up on a clue he spotted in a 40-year-old newsletter: the possibility of video documenting a series of little-known X-15 engineering tests.
After spending the day trolling the archives, Gray found the tape. He hopes to have the X-15 set out by Thanksgiving.
"My release dates tend to be estimates," he says.
Spacecraft Films is online at spacecraftfilms.com.