This story first appeared in the March 7 issue of The Hollywood Reporter magazine.

Space travel has been very good for Sandra Bullock. The 49-year-old actress looks set to earn her biggest paycheck to date for Gravity, with studio sources saying she will make at least $70 million when all revenue streams are factored in.

According to multiple sources, Bullock's deal with Warner Bros. for the Alfonso Cuaron-directed space epic calls for her to earn $20 million upfront against 15 percent of first-dollar gross. That means once her advance is covered, she will collect 15 percent of the studio's slice of the box-office pie, known as "film rentals."

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Each studio negotiates individual deals with theater owners to determine what those rentals are, but a rule of thumb is that the studio will collect roughly 40 to 50 percent of the box office (it gets somewhat less in foreign markets than domestically).

Gravity has earned more than $700 million at the worldwide box office and is expected to cross the $750 million mark. Assuming Warners gets 45 percent of that, Bullock's take would be more than $50 million, including her upfront payment. But theatrical revenue is just one part of what she'll make, as she also gets a percentage from home video, TV and ancillary revenue.

"The theatrical window is going to generate a third of the total revenue a movie will earn; it will get another third on DVD; and then the final third comes from pay and free TV," says one veteran finance lawyer. Gravity might earn proportionately more at the box office, says this lawyer, because "pay and free-TV numbers cap out at a certain point."

Even with a conservative estimate, Bullock will make at least $20 million from those other sources, and she might make considerably more. It is unclear who the other Gravity gross participants are; sources say they at one point included co-star George Clooney, Cuaron and producer David Heyman, though the latter two might have renegotiated their deals when the movie's price tag shot up during its challenging shoot.

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Not that Warners is doing badly. While expenditures increased when elements of the 3D movie had to be reshot, pushing Warners' budget north of $110 million -- and even though it spent at least $100 million more on an extensive and successful marketing push -- the studio benefits from having funded the film almost on its own. The only other entity with a financial stake in Gravity is Brett Ratner and James Packer's RatPac-Dune Entertainment, which has a small percentage. RatPac must wait until the movie's production and marketing costs are covered, and until Warners takes its distribution fee, before seeing a slice of profits.

Bullock's first-dollar-gross deal is highly unusual in today's marketplace, where studios insist on recouping costs before sharing profits with talent. Indeed, several industry lawyers contacted by THR to analyze the terms expressed surprise that she was able to score such a lucrative deal. (Robert Downey Jr. has a similar one on Iron Man films.) But her reps at CAA and the Ziffren Brittenham law firm closed the pact in late 2010 before the belt-tightening now taking place. Bullock also signed on at an opportune moment: Angelina Jolie had dropped out of the film and the studio knew it needed a megastar to carry the drama about a woman stranded in space who spends most of the movie alone.

At the same time, the actress was riding high from an Oscar win for 2009's The Blind Side, which made $309 million globally. Guaranteeing her $20 million against first dollar seemed appropriate, given that there only was one other castmember (Clooney, who replaced Downey).

Gravity is on track to be the most profitable among this year's best picture Oscar nominees; in fact, its profits will be more than those of all the other nominated movies combined. While The Wolf of Wall Street has performed well ($338 million globally), Paramount did not finance the $100 million-plus film and therefore will not see a huge upside; as for the $41 million American Hustle (which has made $217 million globally), Sony will have to split profits with co-financier Megan Ellison. Bullock's rep did not respond to calls and emails. A Warners spokesman declined comment.