Tyranny of the solid rocket motors? [Hyperbola-1 Y8]

i-Space's Hyperbola-1 failed for the fourth time during its seventh flight.

i-Space’s Hyperbola-1 launch vehicle on the launch pad for a previous mission with the Moon in the background.

i-Space attempted to launch its seventh Hyperbola-1 launch vehicle to sun-synchronous orbit from Launch Area 95A at the Jiuquan Satellite Launch Center at 07:40 am China Standard Time on July 11th, or 23:40 pm Universal Coordinated Time on July 10th. This mission was denoted as Y8 despite being the seventh flight, a Y3 launch mission is yet to occur. (Chinese companies, state-owned and private, use Y followed by a number to serialize launch mission numbering, similar to NASA with STS). Three Yunyao-1 meteorological satellites are believed to have been onboard.

The Hyperbola-1 Y8 vehicle’s first, second, and third stages are believed to have fired as planned before an anomaly occurred on the vehicle’s fourth stage. All four of Hyperbola-1’s stages are solid rocket motors, with liquid-fueled attitude control thrusters located on the fourth-stage.

Details on Hyperbola-1 from its users guide.

i-Space is currently performing a launch mishap investigation, with the results expected in the next few months. However, the launch vehicle’s three previous failures could provide some insights.

Hyperbola-1’s first failure is also the least likely to be relevant to this mission. That mission failed due to thermal insulation foam falling onto one of the four grid fins, located at the base of the first-stage. The second failure may be relevant to the most recent launch, in which the fairing failed to separate properly. This could have happened if the fairing got caught on the fourth stage, and led to damage of the casing.

The failure that I currently believe might be the most similar occurred on the Y4 mission, and was also the vehicle’s third failure. That mission failed because one of the attitude control thruster valves became stuck open, causing fuel to leak and run out early. The fuel leak for that flight resulted in a loss of control during the third-stage burn, nevertheless this issue could be repeated and last long enough to occur during the fourth-stage burn.

This latest failure also comes as i-Space is rumored to be facing financial difficulties while trying to develop its partially reusable Hyperbola-3 launch vehicle, which has comparable payload capabilities to Rocket Lab’s in-development Neutron launch vehicle. i-Space was previously the first privately owned launch company to achieve orbit in China, which was also the debut of Hyperbola-1.