Link port caused delay in Oct. 26 Naro-1 launch: ministry

The delay in the Oct. 26 attempt to launch the Naro-1 space rocket, or Korea Space Launch Vehicle-1 (KSLV-1), was caused by a link port (adapter bloc), not an O-shaped ring in the first-stage rocket, said the Education, Science and Technology Ministry on Monday.

Noh Gyeong-won, head of the ministry`s strategic technology development bureau, told a briefing at the Central Government Complex in Seoul, “Scientists concluded that there was a tiny defect on a bar-shaped pipe used as a latch in the middle section of the link port. Thus, the link was loosened and a gap was created in-between the rocket and link port.” As a result, he said, the O-shaped ring within the link port failed to resist high pressure and ruptured.

The cylindrical link port measuring 40 centimeters high and across is the section that connects the inlet at the rocket’s bottom with devices for the supply of fuel and helium gas on the ground. The port is designed to remain attached to the rocket and supplies fuel and helium gas in the course of preparation for lift-off. The latch is released right before blast-off to be separated from the rocket.

Noh said, “We will bring in a new adapter bloc assembly as a whole from Russia, replace it, and test the new one before preparing for launch.”

The new launch date has yet to be fixed. The ministry and the Korea Aerospace Research Institute will pick a date after examining the preparation process for the rocket. Noh said, “We expect to be able to launch it by Nov. 24, which was designated as a preliminary launch date.”

On criticism that authorities might have set a preliminary launch date even before the exact cause of the delay was founded, the ministry said, “The adapter bloc is not a core part that determines the thrust of the rocket like the Stage 1 rocket engine. We set the preliminary date for the launch with ample time to spare by predicting a situation where a part is brought in from Russia and replaced.”

uneasy75@donga.com