SpaceX CRS-7 Accident Investigation Report Released
NASA Independent Review Team SpaceX CRS-7 Accident Investigation Report Public Summary
“The SpX CRS-7 mission consisted of a SpaceX Falcon 9 version 1.1 launch vehicle and a Dragon spacecraft loaded with 4303 lbs (1952 kgs) of cargo. At approximately 139 seconds into flight, the launch vehicle experienced an anomalous event in the upper stage liquid oxygen (LOx) tank, resulting in the loss of the mission. The first stage of the vehicle, including all nine Merlin 1D engines, operated nominally. The Dragon spacecraft also indicated no anomalous behavior prior to the mishap, and survived the second stage event, continuing to communicate with ground controllers until it dropped below the horizon.”
Quite interesting reading. Considering the most likely cause, SpaceX would have been responsible for the issue which caused the accident. Still, even including the pad test failure, their success rate for Falcon 9 is 96%. Excluding the pad test failure, it’s 98%. That’s quite impressive for a company that’s about 10 years old.
And a COPV-less architecture is on the way, with even Gwynne Shotwell now saying an orbital BFR launch as soon as 2020. Spaceship hop/jump/leap tests next year.
To me, this illustrates why Spacex will probably get to the Moon and Mars way before NASA does (if ever). Spacex discovered what the problem was and fixed it relatively quickly, and has been fying most of the time while NASA was still investigating. I understand that this was probably not a high priority investigation, but still.
It probably helps explain why NASA projects are so costly, they investigate and redesign to the point of insanity.
You might want to dig a bit deeper into the report. SpaceX didn’t discover the problem — they blamed it on a subcontractor, when the problem was actually on their end (they used a strut made from an inappropriate material, and it wasn’t used within the manufacturer’s specs).
A more-in-depth summary is here -> https://www.nasaspaceflight…
That’s not what the report (well, the summary of the report) says. It specifically calls “material defect”, the initiating problem SpaceX identified as “credible.” They simply didn’t go so far as to call this the “most probably” cause. The noted a number of other _possible_ causes, on the SpaceX side, which they considered equally “credible.” It could have been a defect from the manufacturer. It could have been SpaceX’s failure to use the 4:1 margin recommended by the manufacturer. It could have been both (e.g. a manufacturing defect which a 4:1 margin would protected against.) It could have been something else entirely. The NASA report doesn’t conclude which possibility was the actually cause. In situations like this, it’s quite common to have too little data to say what “actually” happened.
That’s an awfully large margin in a business where grams are shaved from spacecraft. If it’s more or less standard it’s not something I’d heard before.
A factor of four margin surprised me as well, but that’s what the summary report said. The closest thing I’ve seen is radiation dosage, either for electronics or people. That’s usually a factor of two margin, since the environment is uncertain and realistic testing is impractical.
This might be something similar. If the subcontractor couldn’t test to the right environment (do they have a cryogenic test chamber to rate parts for that temperature?) They might very well have slapped on a huge, recommended design margin. As in “we have no idea how much margin you really need, but a factor of four will definitely be enough.”
You’re blaming NASA for something they didn’t do. The report was finished a long time ago, what was released yesterday is a summary of the report. If you read the summary, it says SpaceX has corrected and mitigated all the findings of the report by January 17, 2016, so the report was finished before that.
NASA kept the report under wraps for more than 2 years, they did SpaceX a favor. I believe the summary is only released because someone in congress specifically asked for it, probably to be used as ammunition against SpaceX.
I like to think the software for Dragon capsules has been updated to the point where the capsule can at least try to save itself in similar incidents.
The Dragon 2, the passenger version, has engines for a launch abort. The software to use them is part of the package. But the cargo version doesn’t have those big Super Draco engines. All it’s got are the much smaller Dracos, and they aren’t enough to do anything during the launch phase. Improved software can’t change that.
That’s certainly true for abort on launch, but if it had been me, I might have put something in its brain for “I’ve been blown free at 45 km altitude, and I’ll bet there’s something useful I can do with my normal re-entry and landing protocols.” Which usually includes a free fall and chute deployment at about 12 km.
I’ve heard people say that the SpaceX people did unsuccessfully try to tell the capsule by radio to attempt chute deployment, but I haven’t heard that confirmed.
Yes, the software was indeed updated, see this article for details: https://www.nasaspaceflight…