Voyager. Cassini. Juice. All three spacecraft performed gravity assists around Jupiter to accelerate their trajectory through the solar system. Would humans use the same technique? What could possibly go wrong if we did? The new movie Slingshot, released Aug. 30, explores that very idea. Filled with mind-bending effects and life-threatening drama, the movie features astronauts on a mission to Titan, Saturn’s exciting moon. As always, it can be hard to tell fact from fiction in a Hollywood science fiction thriller. But the movie got the most important thing right: choosing the destination! Titan is a highly attractive destination for human exploration, but it also represents a goal of monumental proportions. Slingshot wrestles with the challenges of getting to Titan, but leaves you with more questions than answers for how to overcome them.
Titan is a remarkable destination that is even more Earth-like than Mars. This is due to its thick, nitrogen-rich atmosphere, which creates a surface pressure about 50% greater than Earth’s — akin to the pressure of the deep end of a swimming pool — a unique environment in which a pressurized suit might not be necessary. And Titan harbors an amazing landscape with a never-ending list of places to explore. It is the only location in the solar system outside of Earth that is known to have liquid on its surface, with rivers, lakes and seas of liquid methane and ethane decorating the northern latitudes on top of a water-ice crust. Dunes made of tholins, plastic-like hydrocarbons, give texture to the equatorial region. Cryo-volcanoes that replenish the atmosphere may dot the landscape above vents leading to a subsurface ocean of water or methane. In contrast to efforts to find water on the moon and Mars, these diverse features make Titan a treasure trove, with abundant resources to support human missions.
With that background and vision in mind for human exploration of Titan, I return to Slingshot. Without spoiling more than what’s revealed in the trailer, the movie focuses on the long journey out to Titan but includes flashbacks that shed light on the purpose of the mission, the challenges of long-duration space missions and crew dynamics that could go south if the mission is not designed well.
In Slingshot, the purpose of going to Titan is to collect methane and oxygen for use as a clean energy source on Earth — far different from the scientific and exploratory reasons discussed for a real-world Titan mission. Unfortunately, we don’t get to hear in the movie the details of how these resources are collected and transported; they are just used as rationale to kick off the mission planning and crew selection. Setting that aside for a moment, the concept of using methane and oxygen to produce energy is a good one. They are used in rocket engines and would be a valid consideration, backed by academic research, for powering a surface habitat and for fueling a return trip from Titan to Earth. Kudos to Slingshot for capturing the potential for in-situ resource utilization on Titan!
Over the course of the movie, we see the use of hibernation as a way of enabling the crew to endure the long mission to Titan, which is expected to last years. Without a hibernation capability, this would be a very arduous roundtrip mission: the Cassini-Huygens mission took 6.7 years to reach Titan, and NASA’s Dragonfly drone mission launching in 2026 is expected to take 6 years. In 2021, an international research team published an article in the journal Life discussing not only the concept of synthetic torpor, the medical term for induced hibernation, but also how it would help mitigate the effects of radiation exposure, another hazard of long-duration spaceflight. We’ll give Slingshot credit for using it for both benefits.
However, as explored in the movie, hibernation is easier said than done. Drugs powerful enough to induce and maintain a hibernation state could conceivably have undesirable or dangerous side effects. Slingshot capitalizes on this concern as a key theme in the story.
Not explored in the movie, however, is how human missions to Mars could have offered chances to test and refine this capability. Instead the crew is learning as they go along, an approach that doesn’t play out well. Since it is highly likely that traveling to Mars will be a prerequisite for travel to Titan, we would hope for a much better result on the real mission than in the movie.
Slingshot will also have you thinking about how many people would be on the first mission to Titan. The movie shows three astronauts on the voyage but will also give insight into how a solo journey might look. NASA highlighted the importance of determining a crew size to be a major factor in the design and cost of a mission in its most recent Moon-to-Mars architecture definition document. Studies typically converge on a recommended crew size of three to six, with six being the preferred number. Having six crew members ensures use of the buddy system for major activities, the ability for some of the crew to have focused, specialized roles versus being jacks-of-all-trades, and affords the kind of diverse, social interaction and teamwork that you want to see on long missions into the unknown. What is never discussed in the real world is having a crew size of one. Traveling deep into space is a costly affair. Too much time, money and effort is expended in such an undertaking for it all to depend on one person not getting too sick or hurt to perform their duties. In Slingshot, we see the pitfalls of a smaller crew size as they struggle to work as a team and resolve conflicts, putting the mission at risk.
And what about the use of a gravity assist — the slingshot maneuver — around Jupiter? Robotic missions have proven the benefits, so it certainly will be a consideration for a human mission to Titan. You can bet it will be a tense moment when the time comes for that engine burn, just as the movie portrays. But where the movie shows chaos in the face of danger, a real human mission to Titan will have a clear decision process in place for any issues that arise and threaten the safety of performing the maneuver. We will have a well trained crew, operating as a team, using well-tested procedures and flight rules drawn from Mars missions and precursor robotic missions to Titan to guide them to the right decision.
In its portrayal of a human mission to Titan, Slingshot highlights some of the important challenges, and some good and not-so-good ways to overcome them. However, in true Hollywood fashion, these interesting nuggets become overdramatized or underdeveloped. If you are passionate about human spaceflight, you will likely be disappointed with the portrayal of the mission. There was lots of unexplored potential, and they could have done much more with the concept, so the results may leave you hanging. For example, what would entry, descent and landing be like from a human perspective? Remember the seven minutes of terror during the Perseverance landing on Mars? How long would that terror last when trying to land on Titan? What interesting challenges, hazards and surprises might the crew encounter on the surface of Titan? What would it look like to stand on the bank of a methane river? How would Hollywood design a Titan lander or surface habitat? These are questions that the movie, unfortunately, leaves to our imagination.
However, the movie does end with a twist that will have you replaying the entire story in your mind for a long time after you’ve walked out of the theater. That alone makes the movie worthwhile to watch. But while you watch, give more thought to why humans would go to Titan. Consider the real challenges of getting there. And where the movie goes off course, think of better ways to overcome those challenges. After all, the story of a real human mission to Titan has yet to be written.
William O’Hara is founder and executive director of Explore Titan, Inc., a non-profit organization created to explore the idea of making Titan more than a scientific point of interest; it could be the next human destination after Mars. As a veteran of 26 years in the human spaceflight industry, O’Hara is working with planetary scientists to develop educational material, webinars, podcasts and conferences, aimed at promoting the discussion of scientific goals and feasible concepts for human exploration of Titan.
