A combustion test of a 75-ton engine that goes into the Korea Space Launch Vehicle(KSLV)-II was successfully held at the Naro Space Center in Goheung, South Jeolla Province on Wednesday.

The Korea Aerospace Research Institute(KARI) said that it completed assembling a prototype of the first 75-ton liquid fuel engine and conducted a combustion test that lasted 75 seconds. In last month's test, the combustion lasted 30 seconds.

The institute will produce a prototype of the second engine by September and attempt a combustion test lasting 140 seconds.

Instability was reported in the combustion of the domestically manufactured engine, which is the key component of the KSLV, but it appears the problem has been resolved through repeated tests.

South Korea is also in the process of securing technology that enables welding the extremely thin propellant tank without alterations. 

The KARI plans to complete developing the KSLV-II for a test launch by the end of 2017. It also eyes a lunar exploration by 2020. The space launch vehicle will comprise four 75-ton engines, with a first-stage rocket to reach the thrust of around 300 tons.