A fuel filter that dislodged mid-launch is now believed to be behind the failure of Virgin Orbit’s 747 rocket launch in the UK earlier this year.
The business confirmed the findings in a recent release, noting that a “comprehensive” examination indicated that a filter dislodged from its correct position during the launch phase.
This failure is then believed to have resulted in abnormalities in the NewtonFour engine, and the subsequent malfunction of components around the engine.
Virgin Orbit is the successor to a project begun by Virgin Galactic and uses a modified Boeing 747-400 aircraft to launch payloads into space from mid-air.
January’s launch was the first outside the company’s home airport in the Mojave Desert, California, and significantly came before it plans a demonstrator launch at Toowoomba Wellcamp Airport in 2024.
“The data is indicating that from the beginning of the second stage first burn, a fuel filter within the fuel feedline had been dislodged from its normal position,” a release from the company read.
“Additional data shows that the fuel pump that is downstream of the filter operated at a degraded efficiency level, resulting in the Newton 4 engine being starved for fuel. Performing in this anomalous manner resulted in the engine operating at a significantly higher than rated engine temperature.
“Components downstream and in the vicinity of the abnormally hot engine eventually malfunctioned, causing the second stage thrust to terminate prematurely.
“The early thrust termination ended the mission, and the second stage and its payloads fell back to Earth, landing in the approved safety corridor in the Atlantic Ocean.”
While data has indicated the presence of the dislodged fuel filter, researchers are nevertheless continuing to assess all alternative scenarios.
The company is now expected to proceed “cautiously.”
“Our investigation is not yet complete; the team is hard at work and we’ll pursue the cause and contributors to wherever the system analysis takes us,” Dan Hart, chief executive officer of Virgin Orbit said.
“However, with many clear clues from extensive data assessment now understood, we are modifying our next rocket with a more robust filter and we are looking broadly to assure that all credible contributors to mission failure are rooted out and addressed.
“With those modifications being incorporated on our factory floor, we will proceed cautiously toward the launch of our next rocket, which is well into the integration and test process.”
Earlier in the month, Hart alluded to participants at the SmallSat Symposium in California that the launch failed due to a “$100 part”.
“Everything points to, right now, a filter that was clearly there when we assembled the rocket but was not there as the second stage engine started, meaning it was dislodged and caused mischief downstream,” Hart said, as reported in Space News.
“This is like a $100 part that took us out.”
The British government announced in mid-January that the UK’s Space Accident Investigation Authority and the Federal Aviation Administration would jointly lead the investigation.
The launch failure has resulted in the loss of all of the payloads that were bound for orbit aboard LauncherOne, including a UK Ministry of Defence satellite and a US Naval Research Laboratory payload.