MOVIES : Shooting the Moon : America’s hero, Tom Hanks, splashes down for his old friend director Ron Howard in ‘Apollo 13,’ the story of the near-fatal, botched 1970 lunar expedition.

‘Open the door. Let my people go!” bellows director Ron Howard.

As the heavy metal door to Stage 34 at Universal Studios is pried open, the cast and crew of Howard’s latest production, “Apollo 13,” unleash the kind of applause and unrestrained cheering one would more expect from prisoners sprung free after years of captivity.

“Here comes the sun!”

“Off with the jackets.”

“Turn the heat on!”

“Yeah! We’re going back to movie-making!”

Just outside the stage, actor Bill Paxton, outfitted in a white NASA flight suit with space helmet in hand, tilts his face to the sky with his eyes shut tight.

“The sun feels so good. It’s been a real bear! How long have we been in there?” he asks a crew member.

Paxton and fellow cast members Tom Hanks and Kevin Bacon have good reason to celebrate. They have been holed up for many hours a day, nearly 3 1/2 weeks, on a set refrigerated to 38 degrees, cramped inside a mock space capsule too small to stand in.

Finally, Howard, his producing partner, Brian Grazer, and the entire crew can shed the heavy coats, boots and gloves they’ve been wearing to ward off the chill.

Minutes later, on the sunny Universal back lot, as he prepares to film the movie’s final splashdown sequence in a large artificial lake, Howard triumphantly tells the crew on the hill: “We just shot our last cold shot--yeah!”

Howard says that “Apollo 13,” a $52-million production dramatizing the near-fatal botched 1970 moon expedition, has been his toughest cinematic mission ever. It’s the first time he’s ever tackled a true story, though two of his most recent fiction films--”The Paper,” about tabloid journalism, and “Backdraft,” a drama about firefighting--did depict real-life situations and professions.

“Those movies had to ring true, so they were good training ground,” he says, “but we weren’t dealing with a particular event and people who are still alive, and we want to respect that.”

To that end, Howard and his crew are going to great lengths to stick close to the gripping drama that nearly sent astronauts James A. Lovell Jr. (played by Hanks), Fred W. Haise (Paxton) and John L. Swigert Jr. (Bacon) into eternal orbit when their Apollo 13 spacecraft was crippled by an explosion.

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Two days into the real-life Apollo 13 mission in April, 1970, which was to have been NASA’s third moon-walking voyage, one of the two oxygen tanks blew and the main rocket engine was destroyed. The explosion caused a complete loss of oxygen and electrical power, forcing the three astronauts to vacate the command module and use the lunar module (which had a separate engine) as a lifeboat of sorts. The lunar module, designed to accommodate only two, held enough oxygen for 45 hours, which had to be stretched for 90 before the module could be guided back to Earth.

For four days, the world watched as Mission Control in Houston struggled to retrieve the craft. During their perilous journey, the astronauts did not know whether they would suffocate from their own carbon dioxide, freeze or burn up upon re-entry into the Earth’s atmosphere.

“What kept us sane was we had things to do,” says Lovell, a mild-mannered, 67-year-old retired Navy officer and businessman, who served as a technical consultant on the movie. “The idea of how dangerous it was was in everybody’s mind, but we put it aside. As long as we had some options, we were OK.”

Had the crisis not occurred, Apollo 13 would have been almost a non-event. Less than a year earlier, in July, 1969, Apollo 11 put humans on the moon for the first time, but few remember the second moon mission, Apollo 12, in November of that year.

“By the time Apollo 13 came along, the news media and public were bored with the flight up until the accident,” recalls Lovell, speaking by phone from his home outside Chicago.

While the crisis and its ultimate successful resolution were widely covered by TV news as an act of heroism, Lovell says, “after the initial euphoria of getting us home safely wore off, NASA really wanted to forget about it because it wasn’t successful. It was a failure.”

The aborted mission was also a grave personal disappointment to Lovell, who would have been the fifth man to walk on the moon. He was the most traveled man in space up to that time, but his dream to walk on the moon would be lost forever.

“You don’t get many opportunities to go to the moon,” Lovell says. “It was a big downer at the time.” Yet he says that although for years he too had viewed the mission as a failure, he came to realize that “it was a real triumph of teamwork that got us home safely.”

It was primarily NASA’s lack of recognition of the mission more than his own regrets that kept him from writing about the experience.

“(We) really wanted to write about it, but we all had jobs to do,” Lovell says. By the time he retired, in 1991, and was ready to consider writing a book, Haise said he was too busy, and Swigert had died, in 1982. So Lovell hooked up with Discover magazine writer Jeffrey Kluger and wrote a proposal for “Lost Moon” (published last year by Houghton Mifflin), which was optioned by Howard and Grazer’s Imagine Films.

The drama of the story compelled Howard to direct the movie. He says that the film, which will be released June 30 by Universal, is “not a documentary, but part of what makes it entertaining is that it really happened.”

Grazer says that while “for the most part, the movies we are most comfortable making are ones that are overtly humanistic, (“Apollo 13”) involves a whole lexicon of terms and phrases we never heard of--it’s very technical.”

The goal for Howard, and screenwriters William Broyles Jr., Al Reinert and John Sayles, was to strike the right balance between the technical aspects and the human emotion of the ordeal.

“The truth in the story is pretty riveting and suspenseful,” Howard says. “Once you embrace that as an approach to making the movie, you have to work with your imagination to tell a great story, then go through these checks and balances to make sure you’re being true to the spirit of what happened.”

The filmmakers are re-creating, in excruciating detail, what actually went on inside the capsule and at Mission Control, which is why the stage at Universal was set at a near-freezing temperature to simulate conditions in the space module when it lost electrical power. It is so chilly, for example, that cameras can pick up the actors’ breath for effect.

To impart a greater sense of realism, Howard is taking the unusual step of shooting the movie almost completely in sequence. That way, the actors show the continuing physical effects, like beard growth, of the crisis.

Ed Harris, who plays Apollo 13 flight director Gene Kranz, recalls how intense the shoot has been at times: “We’d be 20 guys in there for 20 hours a day, and sometimes by the end of the day, we’d start playing little games, acting like kids, to keep loose.” Harris, who in 1983 played John Glenn in “The Right Stuff,” says he never met Kranz, but he did take a crash course in flight controller school and listened to transcripts from the mission to prepare for the role.

During pre-production, Howard and the actors visited NASA’s Spacecamp in Huntsville, Ala., where they went aboard a space shuttle simulator, then Houston’s Johnson Space Center, home of Mission Control. While on a scouting trip to Houston, Howard discovered that he could shoot his actors in true weightlessness.

He took Hanks, Bacon and Paxton aboard a NASA KC-135 jet, a converted Boeing 707 used to simulate weightlessness in space. As the plane flies straight up, the actors are plastered in their seats by twice the normal force of gravity, then are suddenly lifted up as it plunges to Earth. The plane took the actors on numerous parabolas to produce weightlessness in 23-second intervals as hand-held cameras captured the action.

“This is the first time weightlessness is being simulated on film,” Howard says. “Most space movies skirt the zero-gravity issue because it’s really hard to re-create accurately.”

“Apollo 13” director of photography Dean Cundey (“Jurassic Park”) used a G-cam, a hand-held camera suspended on a cable and counterbalanced to be, in effect, weightless.

“We’re creating camera movement and lighting so that subconsciously the audience will associate what they’re seeing in the movie with what they saw when watching the actual event on TV,” Cundey says.

Back on the ground, Howard is preparing to shoot a crucial scene with Hanks, Bacon and Paxton in which the lunar module is re-entering the Earth’s atmosphere and is at risk of burning up if its heat shield fails.

Former astronaut and on-site technical adviser Dave Scott--who was in a simulator during the Apollo 13 crisis helping in the rescue and drove the lunar dune buggy on Apollo 15--whispers to the director that Hanks’ feet “would not be moving that way if he was pulling five Gs.” Howard suggests that Scott tell that directly to Hanks, who gratefully takes note and thanks him.

If Howard is a perfectionist about authenticity, Hanks is even more fanatical.

“It’s been important to me and Ron that the procedures we were going to be doing were real procedures,” Hanks says after the shot is wrapped. “Dave is always able to say, ‘Here’s what you do in that situation’--it’s great. The best thing this movie has going for it is there’s nothing fake about it.”

Hanks spent four days with Lovell at his home in Texas to research the role. He recalls telling Lovell, “Well, for good or bad, Jim, I’m going to be you. I’m going to be the Jim Lovell of record--and that will haunt you for the rest of your days.”

Lovell says that if anyone can do a good job of portraying him it’s Hanks. He hopes the actor will “show somebody who is human, number one--who had a few misgivings, who didn’t panic up there . . . and who had a wistful remembrance of not being able to land (on the moon).”

When Hanks asked Lovell more personal questions, like, “What did you feel? What were you going through?” he says, “(Lovell’s) answer was always kind of the same, which was, ‘Well, we had a lot to do up there.’ These were terse-lipped men. It’s very evocative to hear someone like Jim say, ‘Yeah, that was pretty hairy’--it speaks volumes.”

From talking to Lovell’s friends and associates, Hanks learned that Lovell was one of the most easy-going astronauts in the corps.

“I was told there isn’t a guy who is faster with a quip,” Hanks says. “Nothing ever fazed him.”

For Hanks, getting the opportunity to play Lovell was a dream come true. As long as four years ago, Hanks says, he had talked to writers about the possibility of a movie version of Apollo 13, and when Lovell’s book surfaced, he was immediately interested. He and Howard had been hoping to work together again since 1984’s “Splash.”

Hanks, 38, says he has been a big fan of space and space travel ever since Stanley Kubrick’s “2001: A Space Odyssey,” which he has seen many times since he was 13. “As opposed to just being moved or entertained by movies, it was the first time that I saw a film that used light and image and sound to tell a story.”

On the set, Hanks is like a contented child standing in his bulky white NASA pressure suit (he says he has always been “fascinated by spacesuits”). The suit weighs so much that two assistants have to help him climb out of it and it gets so warm that air must be pumped in to keep him cool.

Today is the first day the actors are being shot in their spacesuits inside the capsule. It is also the only day that actor Gary Sinise, who co-starred with Hanks in “Forrest Gump,” will be on the set to shoot a scene with his colleague.

“Wait until they put the helmet on Gary!” Hanks says. “He’s going to have 10 seconds of terror!”

Sinise portrays astronaut Ken Mattingly, who was removed from the Apollo 13 crew days before liftoff because he was exposed to the measles. He was replaced on the mission by backup astronaut Swigert (Bacon).

Howard is getting ready to shoot a dream sequence in the module with Sinise, Hanks and Paxton.

The scene depicts a nightmare that Lovell’s wife, Marilyn (Kathleen Quinlan), has before the mission. Lovell had promised his wife that this flight would be his last. She was very superstitious and became anxious when he was bumped up to Apollo 13 after originally having been scheduled for Apollo 14. In the scene, Marilyn Lovell envisions a crack in the capsule, the cabin depressurizing, Mattingly’s face blowing up and her husband being sucked out into space.

“Guys, this is a three-shot in slow motion,” Howard tells the actors. “I’ll yell in the headset, ‘The window is cracking,’ and Gary will throw his weight in that direction and you guys should all push yourselves that way.” He instructs Paxton, “It starts out with you trying to recheck the button. . . .”

Hanks wants to know if he should reach for the button as soon as the lights start going off.

“Yeah,” says Howard, who then tells Sinise: “You’re going to get banged into that (glass) and then sucked out of the hatch, so we’re going to do a shot later when we put you on a teeter-totter, swing you back toward that and then slam you into this post.”

Howard pauses a moment.

“And . . . action! Let’s see the lights flash. Reach for the camera, Tom, that’s it, and a little more slowly . . . lights, lights, arms and hands . . . window! Cut,” he says, bursting into laughter: “Bill, when you reach out, you’re kind of blocking everything.”

A few takes later, Howard is satisfied: “We’re off to a good start!”

After wrapping the sequence, Howard recalls an anxiety dream of his own.

“I always have dreams about the movies I make,” he says. “My first dream on this movie was trying to pitch (Universal Motion Picture Group Chairman) Tom Pollock the idea that the only way to really get this right was to build a capsule on the cargo bay of the shuttle and go up there and film on it. I said, ‘Now, I know it’s going to cost a half billion dollars a flight, but it’s going to be great!’ ”

As the production prepares to switch locations to the lake on the back lot, Hanks, Sinise and Paxton seem relieved to be out of the capsule, in which they were cooped up for more than two hours.

“It’s kind of cozy in there,” Hanks says good-naturedly. “We kept falling asleep (between takes) because it’s so quiet and warm. You hear the whir of the fan--it’s so relaxing.”

Sinise says he barely remembers the Apollo 13 crisis because he was “too busy on Earth playing rock ‘n’ roll and looking for girls,” but he had an hour phone conversation with Mattingly before production began, to talk about his career and how he felt being bumped off the flight. (As it happened, though he was exposed, Mattingly never did contract the measles.)

“He was very devastated by it, although he was a professional and understood the reasoning behind it,” Sinise says. “But he had been training for it for months. It was devastating to the guy and the team because they were in such sync.”

Being the odd man out is what Bacon used as the hook to his character, Swigert, who replaced Mattingly. Sitting in his trailer between takes, Bacon says that because Swigert is dead, he had to rely on research and conversations with those who knew him to grasp his character. In the script, Swigert, a bachelor, was a womanizer, says Bacon, but from what he could find out, that wasn’t accurate. The actor says he specifically chose not to play his character as a Lothario but as “a very smart, hard-working, honest, gentle person--who liked the company of many, many different women.”

Bacon and Paxton say that the tension between their two characters--which existed because Haise, the lunar module pilot, had been very close to Mattingly and thus resented Swigert, the command module pilot--is being played up in the movie. There’s a blowup between Haise and Swigert, both of whom were rookies, about halfway through the crisis that Lovell (Hanks) has to settle. By the end of the mission Haise and Swigert resolve their differences, and Swigert shows empathy for Haise, who becomes very ill with a urinary infection.

Looking weary from the strenuous weeks of shooting in the cold, Paxton says his biggest creative challenge has been “to sell the idea of being a professional astronaut . . . that we really are up there and working these systems.” Paxton, who grew up a space buff in Ft. Worth in the ‘60s and was 13 at the time of Apollo 13, says he and the cast enjoyed themselves despite the physical demands of the shoot. Yet there were days, he says, “when my head was numb from the cold and I’d fill up my bowl with hot water and sit here with my feet in the sink.”

On the back lot, Howard is about to shoot a climactic scene for the end of the movie. A replica of the space capsule sits in the artificial lake, bordered at one end by a huge blue screen. At the other end, a helicopter is positioned on a field, waiting to be cued into action. The background, though the cameras won’t pick it up, looks like a cemetery for abandoned Universal Studios tour buses.

Hanks and Bacon are being outfitted in life preservers for the scene, in which they emerge from the Apollo capsule after splashdown in the Pacific Ocean and await rescue.

As Hanks is escorted to the floating capsule in a rubberized raft, he amuses crew members by assuring them that he won’t forget to take off his sunglasses and boots for the shot. Bacon sits in the rescue basket of the helicopter, looking beleaguered, waiting to be hoisted up to safety.

“I’m just sitting here looking at Kevin and he looks beat to (expletive),” Howard says. “It’s really something to think that these guys (the astronauts) really went through all that and made it back.”

After lunch, back on the now-warmed stages, Howard learns that Universal has just decided to move up the release date of his movie from November to June to compete with the big-budget summer films. This means he’ll have to jam to finish principal photography and accelerate post-production by several weeks to make the early summer slot.

The confident director, who rarely gets rattled on the set, takes the news in stride. He knows that somehow he and his crew will accomplish the mission and have a safe landing.