Scaled statement on SS2 accident investigation

On Friday Scaled Composites issued an accident investigation update about last July’s propulsion system test accident that killed three company employees and injured three others. The statement does not indicate a cause of the accident, and notes that a Cal OSHA investigation that wrapped up in January did not determine a cause. The statement does note that Scaled is making a number of changes, including:

  • Conducting increased compatibility testing between N2O and any materials that contact it in the tank and eliminate incompatible materials in the flow path;
  • Revising cleaning procedures to further minimize the risk of contaminants in the system;
  • Replacing the composite liner in the N2O tank with a metal tank liner;
  • Diluting N2O vapor in the tank with Nitrogen or another inert gas to decrease its volatility and/or act as a pressurant;
  • Designing additional safety systems for the N2O tank to minimize the danger due to tank overpressure; for example, a burst disk feature; and
  • Increasing the amount of testing during the development program to demonstrate that these design changes, and any improvements to system components, prevent the sequence of events
    that led to the accident.

The statement does appear to indicate that Scaled is continuing with a nitrous hybrid propulsion system for SS2.

2 comments to Scaled statement on SS2 accident investigation

  • I cannot believe they used composite tanks without metallic liner :-( to store an oxidizer like N2O, which likes to saturate hydrocarbons and turns them into something unpredictable. Very sad they didn’t issued a detailed analysis of the incident, even if they don’t know exactly what happened (which is my impression now). This would help others to avoid similar catastrophes.

  • Peter

    As of August 18th Scaled has hired SpaceDev to assist in the development and production of their rocket motor.

    It’s interesting that despite their efforts to keep the motor in-house this time they’ve decided to bring SpaceDev in again but I think this is a good move. Without Benson at the helm I guess Burt decided to give them another chance.

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