United Launch Alliance (ULA) suffered what is reportedly its first mission failure in its 20-year history, failing to deliver 40 Amazon Leo satellites to orbit. Leo is Amazon’s competitor to SpaceX’s Starlink, but it has struggled to get off the ground so far, putting only a small portion of the necessary satellites to challenge Starlink into orbit. Today’s launch was supposed to be the first of 38 flights Amazon purchased from ULA.

In a statement posted on X, ULA said, “Based on data received by our Launch Director, we confirm that the Vulcan vehicle launched from Space Launch Complex 41 suffered an anomaly 10 minutes into the flight and failed to deliver the Amazon mission to orbit.”

The company said it was currently unclear what caused the failure, but pledged transparency as it continues its investigation. Amazon projected confidence in its launch partner despite the failure, posting on X that, “ There is risk with any launch, and that’s especially true for inaugural missions like LV-01. ULA has been a trusted partner for Amazon, and we believe they’ll learn from this mission and deliver on their long-term plans for Vulcan.”