Elon Musk explains why SpaceX’s SN10 Starship exploded

SpaceX is already preparing the SN11 prototype for testing, so these trials and explosive errors are still on.

SpaceX Starship SN10 explodes after landing at South Padre Island, Texas, U.S. March 3, 2021 in this still image taken from a social media video. (via REUTERS/SPADRE.COM – TWITTER @SPACEPADREISLE)

SpaceX's SN10 Starship managed to touch down relatively unscathed on March 3 and it seemed like the prototype had managed to clear its test flight. However, the SN10 exploded on its landing pad just a minute after touchdown creating a massive inferno much like its predecessors.

SpaceX CEO Elon Musk has now revealed on Twitter what went wrong with the SN10 in a few responses to followers' queries.

Musk said that the SN10 engine was low on thrust and that was probably due to “partial helium ingestion from (the) fuel header tank”. The impact crushed the rocket's legs and a part of its skirt, Musk said. 

SN10 engine was low on thrust due (probably) to partial helium ingestion from fuel header tank. Impact of 10m/s crushed legs & part of skirt. Multiple fixes in work for SN11.

— Elon Musk (@elonmusk) March 9, 2021

SpaceX is currently working on multiple fixes for the issue so that it does not affect the SN11, SN10's successor that's already being prepared.

Chris Bergin from NASA Spaceflight tweeted that the issue was “tricky one” since the helium ingestion was caused by the pressurisation system added to the CH4 tank to prevent what caused the SN8 Starship to explode.

To this Musk replied that was a “fair point” and said that he had approved the change because it sounded good at that time.

Fair point. If autogenous pressurization had been used, CH4 bubbles would most likely have reverted to liquid.

Helium in header was used to prevent ullage collapse from slosh, which happened in prior flight. My fault for approving. Sounded good at the time.

— Elon Musk (@elonmusk) March 9, 2021

SpaceX's Starship is a heavy-lift launch vehicle that's going to carry cargo and human passengers to Earth's orbit and beyond once it is ready. Despite SN10 blowing up, the SN11 prototype is ready and has been rolled out to the Boca Chica facility where it is going to be prepared for its fourth high-altitude test launch.