Independent safety panel, the Aerospace Safety Advisory Panel (ASAP) has raised concerns about the use of Falcon 9 launch vehicles for crewed missions. In a report released on January 11, the panel recommends NASA delay certifying SpaceX’s commercial crew program.
The ASAP report identified the SpaceX Falcon 9 as a possible area of concern citing the September 2016 pad failure. The failure resulted in the complete loss of the vehicle. Following a full investigation, it was discovered that liquid oxygen had been trapped between the COPV (composite overwrapped pressure vessels) overwrap and liner. The liquid oxygen was then ignited through static or other means causing the Falcon 9 to explode.
Although SpaceX has since changed their loading procedure to avoid similar conditions, both they and NASA have agreed to redesign the COPV. According to the report, NASA has also started a “rigorous test program” to understand how liquid oxygen behaves around the redesigned COPV.
LOC Requirements
The ASAP report has also raised broader safety concerns with the commercial crew program. The report explains that neither provider is on track to meet NASA’s LOC (loss of crew) requirements. LOC requirements set the minimum acceptable risk of a crew suffering serious injury or death.
“The Panel has been monitoring the providers’ progress in working toward the LOC requirements, and it appears that neither provider will achieve 1 in 500 for ascent/entry and will be challenged to meet the overall mission requirement of 1 in 200,” stated the report.
Despite the report painting a worrying picture, NASA expects both Boeing and SpaceX to meet or come close to meeting the requirements. “We have a very difficult LOC requirement to meet, and we knew that going in,” said deputy program manager for the agency’s commercial crew program, Lisa Colloredo.
The LOC requirements imposed on commercial partners are some of the most strict ever imposed on a crewed program. In comparison, towards the end of the Space Shuttle program, the shuttle was only required to guarantee a 1-in-90 chance of “loss of crew”. Although for many, that may not be a comparison worth considering.
Both Boeing and SpaceX have uncrewed and crewed test flights planned for 2018.
Image Credit: SpaceX
