The Space Launch System, or SLS, is a technological leviathan. And NASA has the numbers to back it up. Below are just a few examples of the sheer size, power, and potential of the SLS, NASA’s next chariot to the Moon.

So, as Artemis 1 prepares to embark on a test run around Luna, brush up on your SLS trivia. After all, humanity’s first crewed trip back to the Moon in 50 years wouldn’t be possible without it.

The Artemis 1 SLS rocket is seen here with the American flag draped below it. Though a technological beast, the SLS has also raised many political concerns. 

The Space Launch System is not just a rocket. It’s a political dynamo.

“This has been in the works for years,” NASA Administrator Bill Nelson told the press in the week leading up to the expected launch of the SLS for Artemis 1. “Space is hard.” And that’s true for the politics of space, too.

Nelson has compared the delays and budget overruns for SLS to those of the James Webb Space Telescope, which, he said, has since delivered stunning results. And NASA will be using different contracts in the future, emphasizing contractor efficiency by not rewarding cost overruns as the SLS program and Artemis missions move forward.

“The cost is going to come down,” Nelson says.

Over the years, the projected $10 billion budget for the SLS has doubled, and the debut of the rocket is six years past its initially planned 2016 launch target. The program, set in motion in 2010 by Congress and signed into action by President Obama, relied on modifications to Shuttle-era hardware. That, the thinking went, promised a relatively straightforward and attainable path to launch.

However, it’s been anything but. Critics have referred to the SLS as the “Senate Launch System,” a jab at the budget being spread around to contractors in influential states and Congressional districts. Just as SLS was first getting underway, the Obama administration was also pushing for commercializing launch services. No one had reason to expect the rapid rise of SpaceX’s reusability mantra, one that other companies are now duplicating due to cost savings.

The SLS was never meant to compete with these reusable launch systems. Still, as we set our long-term sights on deep-space exploration, the SLS could be seen as a dinosaur.

For many, it’s been painful to watch heritage SLS aerospace contractors like Boeing struggle to get the rocket off the ground, all while new space startups continue to revolutionize the industry. Initially, Congress, in bipartisan fashion, was appalled by the notion of moving away from large, established, and costly aerospace companies — those which also often serve as defense companies, too. Congress also specifically mandated the SLS development be awarded to Boeing and others, like Northrup Grumman.

In all, the total cost of developing SLS and Orion, as well as a failed rocket predecessor called Ares, is somewhere around $50 billion.

Veteran space watchers wonder if SLS will have a long life now that New Space is nimbly competing with older contractors. SpaceX’s Falcon Heavy costs well north of $100 million per launch. The SLS? About $4 billion per launch, some sources say. And according to veteran space reporter Eric Berger, it’s at least $2 billion per launch.

But don’t forget about SpaceX’s Starship.

“If Starship reaches even half its potential,” Berger writes in Ars Technica, “it will exceed the SLS rocket in every possible way. It's more powerful, far less expensive, and fully reusable, and it can launch hundreds of times a year — not once.”

This much is certain: Barring disaster and assuming a successful first launch, SLS will be NASA’s main workhorse for the time being. But Berger and others have their eyes fixed on Starship, which has the potential for carrying out far more launches at far lower costs. The Starship Human Landing System (HLS) also has been selected as the Artemis missions’ lunar lander of choice. It was a bold move by NASA to do that — a vote of confidence in a company that has already permanently changed the course of human spaceflight. And that decision might have more consequential results too: Starship might even entirely replace the SLS and Orion down the line.

In any case, the Artemis missions are happening. Humans are on a path to deep-space exploration. We are returning to the Moon. Those who have long advocated for this can’t help but be pleased if and when the SLS succeeds. And journeys to Mars look more likely now than at any time since the heyday of the Apollo program.

Like the Saturn V, the SLS may not be as long-lived as its creators imagined. But unused Saturn Vs are museum pieces now. And that’s not such a bad fate for a rocket.

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