An investigation into the failed mission of the first South Korean space rocket, Nuri, in October has found that the early shutdown of its third-stage engine was caused by problems with its oxidizer tank.

According to initial probe results by a committee involving researchers of the Korea Aerospace Research Institute(KARI) and other aerospace experts on Wednesday, the anchoring device of an internal helium tank fell away as buoyancy rose during flight.

The detached tank then caused leaks of helium and oxidizer, prematurely shutting down the third-stage engine.

While reaching the target altitude of 700 kilometers, the rocket came short of placing a dummy satellite into orbit as the third-stage engine burned out 46 seconds earlier than expected.

The science ministry and KARI plan to come up with detailed steps for technological improvements, before finalizing dates for the rocket's second launch set for May.