NASA has been working on the Space Launch System (SLS) as a replacement for the Space Shuttle for a decade, and the project has already consumed $14 billion in funding. It’s not exactly a secret that pure political will has kept the SLS going, but there may have been some casualties along the way. A former United Launch Alliance (ULA) engineer has chimed in on Twitter to tell an anecdote about how the SLS smothered the development of orbital refueling.
Ars Technica reporter Eric Berger had just posted a string of tweets about opposition to refueling depots in congress back when the SLS program picked up steam. Then, former ULA manager George Sowers replied with his perspective. According to Sowers, his ULA advanced programs group had published several papers on the use of orbital refueling depots. He claims his team demonstrated that pre-existing commercial rockets could do the job of something like the SLS. The key was a platform being developed at ULA called the Advanced Cryogenic Evolved Stage, or ACES.
A lot of that was aimed at me and my advanced programs group at ULA. We had released a series of papers showing how a depot/refueling architecture would enable a human exploration program using existing (at the time) commercial rockets.
— George Sowers (@george_sowers) July 31, 2019
In 2011, ULA wanted to test ACES in space to show that it could serve as a refueling depot to get rockets to more distant locations. Sowers said Boeing (which operates ULA along with Lockheed Martin) was incensed by his team’s push for refueling depots. Boeing was, and still is, the primary contractor on the SLS launch vehicle. A shift toward cheaper refueling technology could cost it a juicy government contract.
Sowers says Boeing executives tried to get him fired, but his direct managers held the line. However, ACES was quietly shelved. Around the same time, Berger reports that Alabama Senator Richard Shelby told NASA, “No more f—ing depots.” His home state is home to Marshall Space Flight Center and stood to benefit greatly from SLS development.
ULA says ACES is still on its roadmap, but that could mean any number of things. We do know that NASA is taking another look at orbital refueling. As part of its new lunar push, the agency has partnered with multiple firms on new technology. Among them is SpaceX and its orbital refueling ambitions. SpaceX needs to develop advanced technology to transfer fuel in orbit for future Starship missions, and NASA wants a piece of that.
Meanwhile, the SLS could launch on an uncrewed test mission as soon as next year. The launch has been pushed back a few times already, so it’s just as likely the rocket won’t fly until 2021.