The North Korean Postal Service announces a new stamp that celebrates the launch of the North Korean military spy satellite Malligyong-1, Dce. 21, 2023. Yonhap

The South Korean military said Tuesday that engine combustion problems are behind North Korea's botched space rocket launch and Pyongyang would need "considerable time" to prepare for its next spy satellite launch.

The Joint Chiefs of Staff (JCS) made the assessment a day after a North Korean rocket carrying the satellite, the Malligyong-1-1, exploded soon after liftoff from the Sohae Satellite Launching Ground on the North's northwest coast.

An official of the North's national aerospace agency said the launch "failed due to the air blast of the new-type satellite carrier rocket during the first-stage flight," adding the "accident" was attributed to the operational reliability of a new "liquid oxygen plus petroleum" engine.

"Following its first launch (in May), the North said it will conduct an additional launch as soon as possible, but this time the North only said a preliminary conclusion has been made, raising views it will take considerable time," the JCS official told reporters.

The official said the failure will likely affect the North's plan to place three more spy satellites into orbit this year. In November, Pyongyang successfully placed its first military spy satellite into orbit after two failed attempts in May and August. South Korea's Defense Minister Shin Won-sik told reporters earlier this year that the North's Malligyong-1 spy satellite appears to be orbiting Earth without activity.

Noting that the rocket exploded during its first-stage flight, the official said there may have been issues related to engine combustion but said further analysis is needed. The JCS earlier said the rocket was detected as "multiple fragments" in the North's waters.

On whether Russia supplied the first-stage rocket for the latest launch, the official said while such a possibility cannot be ruled out, more analysis is needed on the extent of technological assistance provided by Moscow.

The botched launch came as Pyongyang and Moscow have been deepening cooperation in a wide range of areas following a rare meeting between their leaders in September. (Yonhap)