On Wednesday Elon Musk’s commercial space company SpaceX launched four astronauts into orbit as part of Inspiration4, the first all-civilian spaceflight mission. They will return to Earth three days later, having made history. Yet apart from collecting data to add to a robust body of research on human health and performance in space, Inspiration4’s value as a research mission is questionable.

While eyes will be on the crew and mission, the game changer to watch may instead be an ongoing SpaceX project in the background: Starship, which the company envisions will be a fully reusable transportation system. In May Starship SN15 became the first prototype of this system to launch 10,000 meters without anything going disastrously wrong. Starship’s inaugural successful orbital flight could come by the end of the year, and a flyby of the moon using the system is scheduled for 2023.

If all goes according to plan, the Starship system would lower launch costs exponentially and usher in a new era of commercial space. Indeed, as the authors of a 2021 white paper for the Planetary Science and Astrobiology Decadal Survey write, “The SpaceX Starship system fundamentally changes the paradigm for NASA science, technology development and testing, and human exploration of space.”

Starship’s promise has everything to do with its size and potential for reuse. SpaceX says the 120-meter tall spacecraft will be able to transport a payload of 100 metric tons, with the greatest volume of any existing launcher. And unlike any other orbital launch system, Starship would be fully reusable, and Musk has said that this could lower launch costs to about $2 million a pop.

Launching a large telescope into space can cost more than $100 million, and reducing that price by two orders of magnitude would have an immense impact on remote sensing, says Waleed Abdalati, director of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder. Depositing payloads of telescopes and satellites into orbit would help climate science in two ways, he says: First, by restocking devices that typically have a three- to five-year life span, Starship could create a cheaper way to carry out sustained observations of our planet. Second, it could enable more ambitious scientific missions as part of the Earth System Explorer program, which capped each one’s cost at $350 million.

“If your launch vehicle eats up $60 million of that [$350 million] or more, already you’re down to a pretty significant limit of resources for your actual mission,” Abdalati says. “If Starship can lower that launch cost, there’s more that can be directed toward the science mission itself.” Astronomers have similar hopes: at least one proposed next-generation NASA telescope has already been vetted by SpaceX for a potential future Starship launch.

Indirectly, Starship could benefit the state of suborbital and orbital science by bringing space debris back down to Earth. Space junk presents hazards to launching vehicles and operational orbiters. And any solution to reduce crowding in the skies would be “tremendously important,” according to Abdalati. Such a cleanup mission could even see Starship recovering dead satellites in SpaceX’s Starlink system as they grow in number—although critics might note that, in this case, the company would be cleaning up its own orbital mess and that removing defunct Starlink satellites does not alleviate the headaches the mega constellation is causing for ground-based astronomers.

Depositing payloads and reclaiming others in orbit is an added perk to Starship’s stated goal, which is ferrying cargo, and eventually crews, to the moon and Mars. According to the recent white paper, whose author list includes researchers affiliated with NASA and SpaceX, the company currently plans to launch multiple uncrewed Starship missions to Mars every two years—each time exploiting a planetary alignment particularly favorable for the voyage. Without a crew, the authors write, there is great potential to unload cargo on Mars as well as to bring back samples from the planet. And similar opportunities exist for transport to and from Earth’s moon. In this regard, especially, Starship’s sheer size is an asset. “Because Starship can return tens of tons of payload from the surface of the Moon, the return sample mass of lunar samples from a single mission would dwarf the combined total returned mass of all lunar samples from all sample return missions to date,” the authors write.

But it is important to interrogate SpaceX’s central claim that Starship can meaningfully lower launch costs, says Pierre Lionnet, director of research at Eurospace, the trade association of the European space industry. A space economist by profession, Lionnet says that people often give outsize attention to launch cost when launching anything into space creates a number of expenses. For instance, the Rosetta space probe and Philae lander, which achieved the first ever soft landing on a comet in 2014, cost the European Space Agency nearly €1.4 billion (about $1.7 billion), but its launch cost comprised less than 10 percent of the total bill.

The ratio of a launch cost to the total cost of creating and deploying satellites, telescopes and other devices determines which organizations will see Starship’s innovation as particularly valuable, Lionnet says. “For a business, reducing the cost of launch can change the economic equation dramatically,” he adds. “For a scientific program, not so much.”

And while a $2-million launch cost is eye-catching, the figure does not tell the whole story, Lionnet says. SpaceX is not a publicly traded company, so it has not disclosed the costs of everything that has gone into the Starship, from building more than a dozen prototypes from scratch to employing an army of designers and engineers. Starship will have to recoup these expenses eventually, Lionnet says. This may, in part, explain the breadth of its proposed applications: SpaceX has promoted the system as not only an interplanetary ferry, space-junk remover and economical launcher for large satellites but also a point-to-point global transportation service capable of sending payloads or people to anywhere on Earth in an hour.

“If tomorrow you open a burger joint, and you tell me, ‘I'm so smart; my burger will be 10 cents instead of $1.50,’ I’d want to know ‘Where are you going to buy your meat? Where are you going to buy bread? How are you going to pay the people who work for you?’ That is exactly what is happening with Elon Musk,” Lionnet says.

Others, such as former NASA deputy administrator Lori Garver, have a more optimistic outlook on Starship. In 2010 Garver helped engineer a federal budget deal that gave NASA funding to develop partnerships with commercial space companies. She says the tenacity of some billionaires’ starry-eyed dreams of space often outweighs their unpredictability.

“Billionaires are a little riskier than a big aerospace company, but I don't think there's any question that, over the long run, they’ll all be in it,” Garver says. “No one’s going to give up.”

She adds that it is in Musk’s best interest to win government contracts and use Starship to aid with research efforts in order to offset the start-up costs he has incurred. Winning those contracts means providing a cheaper service than an agency such as NASA could manage in-house, so there is a fixed upper limit to what SpaceX could charge a federal client. At the same time, Garver says, as Starship launches payloads more efficiently than ever before, Congress will seek to reallocate the funds previously earmarked for NASA’s launch costs. Whether that money will remain with NASA depends on the agency’s success at expanding into areas of public interest, such as climate solutions or human-crewed space exploration, she adds.

“The more we can do that does connect to national interests, the more money we’ll get,” Garver says. “The reason we ramped up during the Apollo program wasn’t because ‘Oh jeez, we want to see what the moon’s made of.’ No, we went to beat the Russians. So what’s our quest today?”

In her opinion, Starship’s stated mission could serve as that quest. Zero-G music performances aside, Musk believes in using the platform to establish a colony on Mars. If you agree with the premise’s value, then everything that goes into achieving this goal might then be considered a worthy scientific exploit, Garver says. And it is not a new goal.

“When I worked at the National Space Society in the 1980s, our mission was to create a spacefaring civilization,” she says. “It just doesn’t take much lead to know we can’t survive on this planet forever.”