SLS Booster Test Failure: NASA’s Rocket Issue Explained

NASA Booster Test for Artemis missions Ends in Fiery Disintegration

NASA’s next-generation solid rocket boosters faced a notable setback during a recent test, raising questions about the timeline for future Artemis missions.The test,intentionally broadcast to the public,revealed a critical failure of the booster nozzle just over a minute into the burn,ultimately leading to its disintegration and sparking a fire.

The incident occurred during the first hot-fire test of the Booster Obsolescence and Life Extension (BOLE) program, a $3.2 billion initiative awarded to Northrop Grumman in 2021. The program aims to develop a more powerful booster for NASA’s Space Launch System (SLS) rocket, crucial for propelling the Orion spacecraft and its crew beyond Earth orbit. The contract encompasses the production of boosters for Artemis missions IV through VIII, and the design and testing of a new booster for Artemis IX.

According to reports, everything initially appeared normal until approximately 1 minute and 40 seconds into the burn, when a plume of super-heated exhaust breached the booster’s structure above the nozzle. Moments later, the nozzle itself failed. As solid rocket boosters cannot be shut down once ignited, the motor continued firing for roughly 30 more seconds until its propellant was exhausted, igniting vegetation in the surrounding hills.

Did you know?-Solid rocket boosters use a propellant mixture of ammonium perchlorate oxidizer, aluminum fuel, and a binder. Once ignited, this mixture burns rapidly, producing hot gas that is expelled through the nozzle to generate thrust.

These boosters are vital to the SLS’s performance,providing over 75 percent of the thrust needed for liftoff.Combined with the 2 million pounds of thrust generated by the four RS-25 engines powering the core stage, the SLS represents a monumental undertaking in space exploration. Northrop grumman has touted the new booster as “the largest and most powerful segmented solid rocket motor ever built for human spaceflight.”

The BOLE design incorporates several key upgrades intended to enhance performance and reliability. A significant change involves replacing the shuttle-era steel cases with lighter and stronger carbon-fiber composite materials. The booster also transitions from a hydraulic to an electronic thrust vector control system for steering. Furthermore, the propellant composition has been altered, utilizing a mix currently employed in Northrop Grumman’s commercial rocket motors, diverging from the formula used during the Space Shuttle program.

Reader question:-given the reliance on solid rocket boosters for initial thrust, what alternative technologies could be developed to enhance launch reliability and safety in future space missions? Share your thoughts.

This latest failure adds to a recent string of nozzle-related issues for Northrop Grumman. in 2019,a test motor for the company’s Omega rocket – later canceled – experienced nozzle loss during testing in Utah. More recently,in 2023,a smaller Northrop grumman booster used on a United Launch Alliance’s Vulcan rocket also lost its nozzle during flight. However, the Vulcan’s guidance system and main engines successfully compensated for the issue, allowing the rocket to reach its intended orbit.

One analyst noted that the recurring nozzle failures raise concerns about the company’s manufacturing processes and quality control. While the Vulcan incident demonstrated a degree of resilience in the overall system, the BOLE program’s reliance on a functioning nozzle for the SLS makes such in-flight corrections unfeasible. The implications for the Artemis program remain unclear, but a thorough examination into the cause of the latest failure will be critical to ensuring the safety and success of future missions.