Launch is hard, but at least now that every rocket is sending extremely detailed live telemetry back to HQ, teams can know what led to a failed launch within days or weeks. Case in point: Virgin Orbit’s much-hyped first launch from U.K. soil last month, which did not achieve orbit — apparently due to a single loose fuel filter.
In an update posted today to its website, Virgin Orbit explained first that everything went perfectly at every step leading up to the issue, including ignition, first-stage flight, stage separation, second-stage ignition and fair deployment — all moments when mission-ending failures can occur.
But that’s when things leave nominal:
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.
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.
For want of a filter, the mission was lost. It’s a sobering reminder that launch vehicles when they succeed are collections of thousands of moving parts operating in perfect precision — or at least within tolerances.
A fuel filter that is not secured properly, or with some minor manufacturing defect that causes it to shimmy loose, is the butterfly flapping its wings, causing the hurricane downstream. It all happens in a handful of seconds, but the data sent back will be clear enough to the engineers when they have the time to look at it later.
So what’s the solution? At the very least, a new fuel filter, says Virgin Orbit’s CEO, Dan Hart:
“Our investigation is not yet complete… 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.”
Thusly will they “proceed cautiously” toward their next launch, from the U.S.; a commercial payload the details of which they expect to announce in a few weeks.