As the air-breathing engine, the performance of solid rocket ramjet is determined not only by structure of engine and the performance of propellant, but also by flight condition.

作为吸气式发动机，其性能不仅取决于发动机本身结构和推进剂性能，与飞行状态也有密切的联系。

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Beyond this 200-day limit, the confidence in the performance of the vehicle drops off, and in particular in the status of the propellant in their manoeuvring thrusters.

BBC: November deadline for ISS crews