Astronomers breathed a collective sigh of relief as the James Webb Space Telescope (JWST) sprung to life. Getting the $10-billion telescope up and running following its launch on Christmas Day 2021 had been a nerve-racking affair. JWST would not fit into any modern rocket without being folded, and it had to rely on hundreds of moving parts to unfurl to full size once in space. Ultimately those efforts were successful, and the telescope has started returning some of its first calibration images to thrilled audiences back on Earth. Yet the experience left many astronomers wondering if there was a simpler way to build and launch telescopes of this size. “We were worried about the unfolding,” says John Blevins of NASA’s Marshall Space Flight Center. But with a larger rocket, “you don’t have to unfold in space. You can do it on the ground.”

As chance would have it, two such rockets are currently sitting on launchpads. Each should ultimately exceed the power of the mighty Saturn V, which sent the Apollo astronauts to the moon. The first, NASA’s Space Launch System (SLS), is ready and waiting at Kennedy Space Center in Florida for its inaugural uncrewed voyage around the moon this summer as part of the Artemis I mission—the opening shot in NASA’s plan to return humans to the lunar surface in the 2020s. The rocket is meant to be as reliable as possible and is therefore based, in large part, on legacy hardware from NASA’s Space Shuttle program. But a reliance on tried-and-true technology could be its Achilles’ heel: some estimates currently peg the SLS’s cost at an eye-watering $4.1 billion per launch. Presuming it is not scuttled by congressional appropriators feeling buyer’s remorse, its massive size could ultimately be a boon for scientists seeking to send larger, more ambitious spacecraft and telescopes throughout the solar system—and even beyond.

Over in Texas, Starship, a similarly capable but wildly different rocket being developed by SpaceX, is also in preparation to launch on its first orbital test flight as early as May, pending regulatory approval from the Federal Aviation Administration. The cost of the SLS seems so egregious because each multibillion-dollar rocket will be discarded after a single use, its components relegated to junk on the seafloor or adrift in space. Such was the standard for most of the space age, but times have changed. Starship and its giant Super Heavy booster are instead built for endurance, landing back on the ground for rapid reuse similar to SpaceX’s current fleet of Falcon rockets, which has already dramatically lowered the cost of reaching space. As big and bold as the SLS may be, experts say that it pales in comparison with what Starship could achieve. “Starship holds the promise of transforming the solar system in a way we can’t really appreciate,” says Alan Stern of the Southwest Research Institute in Texas, who helms NASA’s New Horizons mission, which flew by the dwarf planet Pluto in 2015. “It completely changes the game.”

To read more, click here.