Jeff Bezos’ space company Blue Origin released findings from an investigation into the failed flight of a cargo mission last year, which it says was due to an issue in the rocket’s engine nozzle.

The company’s New Shepard rocket, flying the NS-23 mission carrying science and research payloads, suffered a failure in September 2022. No people were onboard, and Blue Origin says its capsule’s emergency escape system functioned properly, but the rocket’s reusable booster was destroyed.

Bezos’ company had previously said little about its investigation over the past six months, which was conducted with Federal Aviation Administration oversight.

In a blog post on Friday, Blue Origin said it identified “a thermo-structural failure of the engine nozzle” as the direct cause of the issue, and is now modifying the engine, including design changes to account for higher-than-expected temperatures during the flight.

“Blue Origin expects to return to flight soon, with a re-flight of the NS-23 payloads,” the company said.

The New Shepard rocket launches from Blue Origin’s private facility in West Texas, carrying people and payloads above 100 kilometers — or more than 340,000 feet — for a couple minutes of weightlessness. The capsule is flown autonomously, with no human pilot, and floats down with the assistance of a set of parachutes to land in the Texas desert. The New Shepard rocket booster is reusable, returning to land on a concrete pad near the launch site.

Blue Origin said its investigation found that NS-23 flight’s engine failure was due to “operational temperatures that exceeded the expected and analyzed values of the nozzle material.” The company recovered fragments of the BE-3PM engine’s nozzle, finding “clear evidence of thermal damage and hot streaks resulting from increased operating temperatures.”

The company noted that its design changes are intended to improve the engine’s performance at high temperature, as well as strengthen the engine’s nozzle.