The upper stage will have a smaller engine, says Meng, without giving details.

上面级将有一个更小的发动机，孟说，没有透露更多细节。

youdao

The upgrade - known as Ariane 5ME (Mid-Life Evolution) - would introduce a more powerful upper-stage engine.

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Work will continue to give Ariane 5 a major upgrade, to provide it with a more powerful upper-stage engine that will also have a stop-start capability.

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