by Douglas Messier
Nearly three years after a SpaceX Falcon 9 failed in flight sending a Dragon resupply ship to the bottom of the Atlantic, NASA has finally released a public summary of its own investigation into the accident. [Public Summary — PDF]
You might recall that SpaceX’s internal accident investigation blamed a defective strut assembly in the second stage liquid oxygen (LOX) tank. The strut, provided by an outside supplier, snapped under launch stresses, causing a helium bottle inside the tank to break free and destroy the LOX tank, the company said.
The NASA investigation found that is a credible scenario for the accident. However, the space agency blamed a “design error” by SpaceX. The table below shows a summary of the investigation’s technical findings.
The report also questioned the use of other materials in the booster, although they were not directed related to the launch failure.
Investigators also concluded that a new process implemented for the Falcon 9 Full Thrust variant led to “a substantial portion of the anomaly data being lost.”
Why is took NASA nearly three years to release the public summary is an interesting story. You might recall that I pestered NASA back in 2016 asking when the report would be released. In December of that year, I was told to check back in six months.
When I checked back in July 2017, NASA told me the agency had no obligation to release a report; therefore, it would not do so. I chronicled the sage in this story.
About a month later, I discovered a provision in the Senate appropriations bill requiring the FAA to release a report on the accident that would include the findings of NASA’s investingation.
“The report must consolidate all relevant investigations by, or at the request of, the Federal Government that were conducted, including those completed by NASA as part of the FAA report, and must also include a summary suitable for public disclosure,” according to a committee report that accompanies the spending bill.
I haven’t had time to fully digest this report, so I will read it tomorrow and write more if warranted.