SpaceX says it has discovered why one of its spacecraft exploded during a ground test in April. A valve inadvertently leaked some of the vehicle's propellant causing a chain reaction that caused the spacecraft to burst. After determining the cause, SpaceX will replace these parts in all future versions of the vehicle to ensure that this explosive leak does not recur.
The spacecraft that lost SpaceX was a trial of Dragon's crew, a capsule built for NASA to bring astronauts to and from the International Space Station. This particular capsule was the very first Crew Dragon SpaceX had ever launched into space. In March, the vehicle successfully landed at the ISS, with no crew, before returning to Earth during a flawless test mission. In routine vehicle testing on April 20, the capsule broke violently and blew orange gas into the sky.
SpaceX formed an investigative team immediately after the accident to find out what had caused the explosion, and the company has been working with NASA ever since. Until six weeks ago, however, SpaceX had not limited the exact cause. With the discovery of the leak, the company now says the investigation is about 80 percent complete. "It's hard to say how much time we need to finish this," said Hans Koenigsman, Vice President of Construction and Flight Safety at SpaceX, during a press conference. "But you want to make sure the capsule ̵
The Company Believes The problem arose from Crew's emergency response system, which consists of a series of small engines embedded in the capsule. If everything goes well during a mission, these tiny engines are never intended for use. However, should a failure occur during a future launch, the engines may ignite the Crew Dragon and safely carry it away from a collapsing missile.
According to SpaceX, a leaky valve has channeled the propellant needed by these engines into another system – one of really high pressure. As this contamination occurred, the high forces threw the liquid around, resulting in the failure of valuable components and the final loss of the capsule.
Koenigsman said this contamination was definitely not expected, even though the type of valve that leaked out was known to have internal leakage problems. Eventually, he acknowledged that this was, to a degree, a design issue. "It's something the components should not have done," Koenigsman said. "At the same time, we have learned a very valuable lesson for the future that will make the Crew Dragon a safer vehicle."
SpaceX Will Replace Everything These valve types come with a different component called a rupture disk which, according to Koenigsman, should be much more reliable. SpaceX indicates that there are many Crew Dragons at various stages of production at the company's headquarters in California. However, it is unclear when the Crew Dragon will fly again. Prior to the explosion, SpaceX had planned to fly the first astronauts by the end of the summer. Now it is becoming more and more likely that SpaceX will be hauling people until the beginning of next year – although Koenigsman will not rule out a flight in 2019. "My focus is really on making sure it's safe," he said. "At the end of the year, I do not think it's impossible, but it's getting harder and harder."
A NASA representative, however, was grateful for the failure, especially as it happened not on a flight but on the ground. "We had the opportunity to find a hardware problem, find the hardware and evaluate the hardware," said Kathy Lueders, program manager for NASA's Commercial Crew Program, during the press conference. " So it was a great gift for us."