exploration upper stage

Ding-dong! The Exploration Upper Stage is dead

Now, you might think NASA would ask industry for solutions to this problem. After all, United Launch Alliance was developing a more powerful upper stage for its Vulcan rocket, the Centaur V, that used the same propellant as the core stage of the SLS rocket. And Blue Origin was also developing a powerful upper stage engine, the BE-3U, powered by hydrogen. These options were cheaper, available, and … summarily ignored.

10 years, billions of dollars, and not much to show for it

Congress, smelling jobs, wanted NASA to develop a brand new upper stage. So in 2016, lawmakers allocated $85 million for preliminary work on the upper stage, and have since awarded more than $3.5 billion.

For the development of a rocket’s second stage.

With engines (RL-10s) that have been flying in space for six decades.

And after all of this, a decade later, the upper stage remains years from being ready to fly.

In some ways, the Exploration Upper Stage was the perfect vehicle for pork. It not only spread largesse among Boeing and Aerojet Rocketdyne (for the engines), but it also necessitated a massive new launch tower in Florida. That was good for the Exploration Ground Systems program at Kennedy Space Center.

The original cost estimates of these projects are always instructive to look back on. Boeing’s initial contract to build the Exploration Upper Stage started at $962 million, and NASA planned to launch the rocket on the second flight of the SLS in 2021. Oops. As for the launch tower, the initial estimate for its cost was $383 million, but as of late, it was heading north of $2 billion. So we are talking billions and billions and billions of dollars for a relatively straightforward upper stage, using off-the-shelf engines and a large launch tower.

Congress and Trump may compromise on the SLS rocket by axing its costly upper stage

exploration upper stage, NASA, sls, Space, Trump / Rejus Almole / September 8, 2025

There are myriad questions about how NASA’s budget process will play out in the coming weeks, with the start of the new fiscal year on October 1 looming.

For example, the Trump administration may seek to shut off dozens of science missions that are either already in space or in development. Although Congress has signaled a desire to keep these missions active, absent a confirmed budget, the White House has made plans to turn off the lights.

Some answers may be forthcoming this week, as the House Appropriations Committee will take up the Commerce, Justice, and Science budget bill on Wednesday morning. However great uncertainty remains about whether there will be a budget passed by October 1 (unlikely), a continuing resolution, or a government shutdown.

Behind the scenes, discussions are also taking place about NASA’s Artemis Program in general and the future of the Space Launch System rocket specifically.

$4 billion a launch is too much

From the beginning, the second Trump administration has sought to cancel the costly, expendable rocket. Some officials wanted to end the rocket immediately, but eventually the White House decided to push for cancellation after Artemis III. This seemed prudent because it allowed the United States the best possible chance to land humans back on the Moon before China got there, and then transition to a more affordable lunar program as quickly as possible.

Congress, particularly US Sen. Ted. Cruz, R-Texas, was not amenable. And so, in supplemental funding as part of the “One Big Beautiful Bill,” Cruz locked in billions of dollars to ensure that Artemis IV and Artemis V flew on the SLS rocket, with the promise of additional missions.

Since the release of its budget proposal in May, which called for an end to the SLS rocket after Artemis III, the White House has largely been silent, offering no response to Congress. However that changed last week, when interim NASA Administrator Sean Duffy addressed the issue on a podcast hosted by one of the agency’s public relations officials, Gary Jordan:

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