Alien, Avatar and Passengers are science fiction blockbusters with one thing in common. No, it’s not the earnings of the lead actors but the business model that underpins the plot. Each movie has a premise that involves long trips into space to transport something to or from Earth.

In Alien the crew of the ship is towing a refinery back home. The refinery has been stocked with materials extracted from another planet. The concept of resource exploitation is revisited in Avatar, where the exomoon Pandora is mined for a mineral that has enormous value on Earth. Passengers has a related theme—a company called the Homestead Corp. operates spaceships that transport thousands of people on one-way trips to colonize new planets.

Although science fiction aficionados will have no problem suspending belief about the technology imagined in each of these films, fans with a keen eye for profit may be left scratching their heads.

The reason is simple. Each of the journeys in these films—and others that share a similar plot—is presumed to take decades. In Passengers, for example, each one-way trip takes 120 years—and herein lies the issue. With time frames like this, the business model that is the foundation for these movies—and many others like it—is unlikely to be viable because of the delay involved in paying back any initial investment in the venture. This is important because it starts to throw light on how interstellar exploration is likely to evolve.

To understand this further, I talked with filmmaker James Cameron, who wrote, directed and produced Avatar. Cameron says the movie is more of a fable about how humans have treated Earth, and the plot hinged on the premise that the mineral mined on the planet was so valuable it made economic sense to transport it back. In reality Cameron says, “the best thing to bring back would be data—about new genomes, materials, etcetera.” He makes a valid point—sending data to Earth could simultaneously create tremendous value and negate the need for a ship to transport physical materials.

Even financing a project that returns data rather than tangible cargo, however, has investment horizons that would make hardened long-term investors uneasy—even more so in an era where corporate longevity is declining. This is because since 1970 the average life of a company in the U.S. has nearly halved. If this trend continues, will any organization in the future survive long enough to be able to invest in projects that will outlast the average company?

Leslie Hannah, professor [of Economic History at the London School of Economics and Political Science, points out that today it’s even hard to fund projects that have a 20-year payback. Hannah acknowledges there are some businesses operating today that have survived for hundreds of years. In the finance sector one of the largest of these is the British banking firm Barclays, which can trace its origins back to 1690.

Despite the existence of such organizations, Hannah “cannot think of a historical precedent” for the investment cycle that would endure a payback cycle with the duration imagined in popular science fiction movies. The closest parallel he cites is building the Suez Canal, which was entirely privately funded. The structure of the Suez deal meant the project would provide small returns over a long time frame, but shareholders had a relatively fast payback. When pressed about government funding, Hannah says that although nations can borrow at very cheap interest, there have been “lots of ups and downs about the fashion of investment of governments.”

Currently one of the most forward-thinking government investors is Singapore, which regularly considers long-term investment cycles. Gareth Wong Wei Han, a group director in Singapore’s government-linked portfolio company, Surbana Jurong, one of Asia’s largest urban, industrial and infrastructure consultancy solutions providers, says that even with this mind-set, “80 years is a really long time horizon.”

Given this, is it feasible to assume that space exploration in the future will take a form that’s favored by Hollywood?

Sir Martin Rees, Astronomer Royal (among many other prestigious roles), expects this century will see a golden age of space exploration by small robotic ships that cost relatively little. He maintains, “the practical case for manned spaceflight gets ever-weaker with each advance in robots and miniaturization.” Cameron agrees that small, self-replicating machines are likely to be the model that succeeds for travel into deep space.

Regardless of the physical form of space exploration—and whether or not it includes humans—the timescales are still daunting. For context, earlier this year a series of Earth-size planets were discovered. Astronomers considered these to be relatively close. But even so, a ship traveling close to light-speed would have an 80-year round trip. Travel at this speed would require a fundamental change in the laws of physics. But with the current pace of technological development, it is far more likely computers would become as capable as a human brain before light-speed travel is (if ever) perfected.

Machines with the ability to “think”—known as artificial general intelligence—would be well suited for interstellar travel. They would probably weigh less than humans and be unconcerned about maintaining life-support systems and the longevity of space travel. This raises another question, however: Why would an artificial intelligence would want to embark on a mission that benefits humanity? Cameron suggests an answer to this—incentivize spacefaring computers by giving them equity in the profits.

Now that sounds like a great plot for a science fiction movie.