SpaceX held a press conference on Monday to discuss the results of a month-long investigation conducted by him and NASA during a static fire test in April. The investigation revealed that the "anomaly" that occurred during the test was the result of an oxidant mixture at very high pressure with the helium component of the SuperDraco rocket propellant system.
On April 20, SpaceX engine crashed off test for a prototype of its Crew Dragon vehicle (which had previously flown for the unoccupied ISS mission). Crew Dragon was the first SpaceX spacecraft to be developed for the crew and is undergoing a series of tests to prove its readiness to fly for NASA. The test encountered an error that became immediately apparent after the first tests proved successful. An unexpected explosion produced a cloud of fire that was visible for miles around the test site at the Landing Zone 1
SpaceX Hans Koenigsmann, BP of Build & Flight Reliability, and NASA's Commercial Crew Program Manager Kathy Lueders shared the results of their joint investigation of the causes of this anomaly with the media. Koenigsmann explained that by detecting traces of combustion around a check valve in the system, the pressurized oxidant and fuel components should be separated from each other. These check valves include a spring that can be opened and allows flow in the direction in which the propellant components should flow. In this case, a leaking check valve resulted in a "surge" of high pressure oxidant which impinges on a titanium component resulted in a very violent reaction, hence the explosion.
Both Lueders and Koenigsmann found that this was "a gift" in many ways, as there were many high-speed cameras that could capture the incident, and it was relatively easy to comb the site and restore components, to best determine the cause of the anomaly. Koenigsmann also noted that the team is confident in reporting these results, but that there are only about 80 percent of examinations left, and that about 20 percent is left to find additional details, especially in terms of the physics involved.
Koenigsmann SpaceX has already implemented an important hardware correction to replace the check valve with a burst valve. A burst valve completely separates the oxidizer and fuel from any pressurized fluid, alleviating this problem and making Crew Dragon a safer vehicle.
So far, SpaceX has been able to launch an unscrewed version of this year. The Spacecraft Crew Dragon 2 was to be brought to the ISS during a mission in March and had planned the first test mission with crew in July this year with a mission duration of two weeks to complete. That definitely will not happen on that timeline, and now the ongoing production of Crew Dragon vehicles will repel the foreseen engines of a generation, meaning that the intended Crew Dragon 1 vehicle for manned mission flight is now Test 2 and so on.  Repeatedly in the news, neither Koenigs- mann nor Lueders would offer anything concrete, but both expressed skepticism about launching by the end of the year, without excluding the possibility altogether.
"There is always the possibility that we crew will be flying on a SpaceX vehicle this year," Lueders said, but continued that "NASA" is currently "watching" all running tests on different systems and "all these things are occurring before we can be sure the system is safe Fly with our crew. "" I hope it's this year, "she added.
Koenigsmann noted that this is an issue that he is fairly certain will be able to tackle in parallel with other things that need to be addressed with Crew Dragon before the crew flight. "I do not think it's impossible, but it's getting harder and harder," he said when asked directly after a dragon launch with a crew scheduled to take place before the end of 2019.
Lueders concluded by thanking SapceX for its openness to NASA and its astronauts throughout this process, and Koenigsmann reinforced the superiority of the bursting valve over the non-return valve that replaced it for this application.