The spaceship will be fuelled by a "hybrid rocket" -so-called because it contains both liquid and solid propellants.

飞船将使用液体与固体混合的助推剂作为燃料。

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Liquid-fuelled rocket engines work by mixing the fuel (in this case kerosene) with liquid oxygen at high pressure.

ECONOMIST: On a rotor-blade and a prayer | The

"That activity may be related to another round of modifications intended to support future launches of the Unha rocket or possibly another liquid-fuelled missile, " 38 North said, while cautioning that more information was needed.

BBC: North Korea 'upgrading rocket launch site'