China’s space race has a new problem: finding room for failure

There is something about the speed of consensus on China’s rocket failures that should give us pause. Within hours of Long March-7A rocket’s disintegration over the South China Sea on August 10, trade reports were pointing to an engine as the likely culprit. The China Aerospace Science and Technology Corporation (CASC) had said nothing of the kind. An official Xinhua report about three hours after the launch described only “a flight anomaly” and an investigation under way.

The cause is unknown, yet explanations are fast becoming a story of their own.

Neither of the two explanations in circulation has official backing. One points to the YF-100, the kerosene-oxygen engine that powers the 7A rocket’s first stage and four boosters. The engine is also used for the Long March 5, 6, 6A and 8, as well as the newer 10 and 12. The other explanation points to a possible structural failure near Max-Q, the point during ascent when the rocket faces its highest aerodynamic stress. Independent space flight trackers reached this view after studying the launch footage frame by frame.

Some trackers argue that the brief engine anomaly, seen before the break-up, happened too quickly to explain what followed. Others think an engine problem could have triggered a structural failure under heavy aerodynamic loads. But these are arguments and observations derived from the footage, rather than a confirmed finding.

Still, both explanations start with the same fact: the failure happened about 85 seconds after launch, during the burn of the first stage and four boosters.

That was well before the firing of the third stage, which uses the YF-75 engine involved in the Long March-3B failure in January. Both failures involved different parts of the rocket. The 3B failure involved the YF-75 upper stage. The 7A failure happened during the first-stage and booster burn. There is no evidence that both failures share a cause.