The PALAPA-D/LM-3B flight anomaly investigation was concluded in early November 2009.
China Academy of Launch Vehicle Technology (CALT), the launch vehicle manufacturer, and Academy of Aerospace Propulsion Technology (AAPT), the third stage engines manufacturer, formed the Investigation Committee and conducted the analysis and study on the malfunction phenomenon which occurred during the LM-3B/PALAPA-D flight on August 31, 2009, when the thrust of one of the third stage engines was lower and the satellite was sent into an orbit which is lower than the pre-determined super-geostationary transfer orbit. For more than two months, the malfunction investigation covered the flight data interpretation and analysis, possible malfunction causes and mechanism study, malfunction modes establishment, corresponding ground tests and verifications as well as the computer simulations. And the malfunction phenomena were repeated during the ground tests. The investigation conclusion made by the Investigation Committee was reviewed and passed by the Oversight Committee of China Aerospace Science and Technology Corporation (CASC).
The investigation result shows that the cause for the abnormal decrease of the third stage Engine I is the local leakage of the gas generator resulted from the local heat ray and flux, which was induced by the foreign objects blocking the liquid hydrogen injectors.
In accordance with the malfunction cause, corresponding corrective actions were taken and the ground testing verification was passed. The corresponding corrective actions will be flight-proven in the next flight of a LM-3A series.