The timetable for the first manned flight of the SpaceX Crew Dragon may have been thrown into question after the spacecraft appeared to suffer a serious engine malfunction. On April 20 at Cape Canaveral, Florida, an "anomaly" was reported during a static fire test that may have resulted in the release of toxic rocket propellants.
Precise information is still very scarce on the ground, but a report in Florida Today says that one of their photographers on assignment at Cocoa Beach, near Cape Canaveral, witnessed orange plumes rising from the NASA space center at about 3:30 pm EDT, where the Crew Dragon was undergoing static fire tests. Which Dragon was used is unclear, but the Crew Dragon that recently visited the International Space Station (ISS) was scheduled to make a series of post-flight tests.
"On April 20, 2019, an anomaly occurred at Cape Canaveral Air Force Station during the Dragon 2 static test fire," said US Air Force spokesman Jim Williams. "The anomaly was contained and there were no injuries."
In a later statement, SpaceX said, "Earlier today, SpaceX conducted a series of engine tests on a Crew Dragon test vehicle on our test stand at Landing Zone 1 in Cape Canaveral, Florida. The initial tests completed successfully but the final test resulted in an anomaly on the test stand.
"Ensuring that our systems meet rigorous safety standards and detecting anomalies like this prior to flight are the main reasons why we test. Our teams are investigating and working closely with our NASA partners."
Meanwhile, NASA administrator Jim Bridenstine posted on Twitter, "NASA has been notified about the results of the SpaceX Static Fire Test and the anomaly that occurred during the final test. We will work closely to ensure we safely move forward with our Commercial Crew Program."
The exact nature of the mishap aboard the craft that is designed to ferry passengers into space has still not been made public, but it appears to center on the eight SuperDraco engines. These were originally designed to allow the Crew Dragon to make a ground landing, but are now used as the emergency abort rockets to get the capsule clear of the launch pad in the event of an emergency.
The SuperDraco is a restartable, throttelable engine that is powered by a mixture of monomethylhydrazine fuel and dinitrogen tetroxide oxidizer. These provide each engine with 16,000 lb of thrust, but the propellants are highly volatile and toxic. They are also hypergolic, which means that they ignite on contact with one another. As a result, any leak during a ground test is dangerous and a simultaneous leak of fuel and oxidizer can be catastrophic.
The cause of the accident and the details are still unknown, or unreleased, and the impact is still uncertain. However, because Crew Dragon must pass very rigorous standards before it is declared safe to carry astronauts, anything other than the most minor of mishaps is likely to result in an extensive review – therefore, the first manned Crew Dragon mission, which was scheduled for sometime after July 25, is now likely to be pushed back.
Source: Florida Today