Ⓒ JoongAng Ilbo / JoongAng Ilbo Japanese version2022.06.18 09:31
The Korean rocket “Nuri” (KSLV-II), whose launch has been postponed twice, will challenge the launch again on the 21st. On the 17th, the Ministry of Science and ICT announced the second launch schedule of the Nuri, which was decided at 4:00 pm on the 21st, at a briefing on the current status of the Nuri inspection and future plans.
After the Nuri was moved from the assembly building to the second launch site on the 15th, an error was found in the sensor of the first stage oxidizer tank during the inspection process, and the launch was canceled. Following the postponement of movement to the launch site due to strong winds on the 14th, the launch was postponed due to a problem with the aircraft on the 15th, and it seems impossible to launch on the 16th to 23rd of the preliminary day. Was out.
The Korea Aerospace Research Institute (Korea Aerospace Research Institute) moved the Nuri from the assembly building to the launch site on the 15th, and then inspected the level sensor in question until the 17th. The research team considered the cause of the level sensor problem to be a problem with electric wires, signal boxes, and sensors, and proceeded with the inspection. On the 16th, the wires and signal boxes, which are relatively easy to inspect, were inspected, and these parts were judged to be normal. At the inspection status briefing conducted on the 16th, Ko Jung-hwan, general manager of the Korean projectile development division of Kouken, said, “If there is a problem with the level sensor instead of the electric wire and signal box, the connection between the first and second stages Needs to be separated and takes time. “
◆ Sensor problem that separation is necessary … How did you solve it?
However, the Kouken side explained at the briefing on that day, “Although it is a problem with the level sensor, it was not necessary to separate the first and second stages, and the parts could be replaced.” Regarding the fact that the level sensor problem could be solved without separation, he explained, “After careful inspection, we decided that it would be better to replace the electrical parts rather than replacing the entire level sensor.” The researchers reviewed the drawings to determine if separation was necessary, discussed whether a person could enter the area and replace the electrical components, and in fact, based on the decision that it was possible, this day. It is said that the parts were replaced in the afternoon.
The parts replaced by the researchers on the Nuri are electric core parts with a length of about 1.2 meters. The level sensor in the oxidant tank measures the value by moving the float along the pillar. The principle is that electricity flows through the electric part inside the pillar to generate a signal, and the float outside the pillar moves while measuring the position. The researchers explained that it was possible to solve the problem without separating the first and second stages by replacing only the electrical part inside the pillar, not the entire sensor. A person entered the interior of the Nuri and replaced this part, and the part used for the third launch was to be used for the second time. However, the cause of the problem in the electrical department is still being understood.
The Kouken side said, “The replacement of parts does not cause a burden on the aircraft.” “Many parts are inside the Nuri, and it cannot be said that there is no 100% problem this time, but through this process. It can be said that the possibility of the problem is further reduced. “
◆ If you forcibly adjusted to the preliminary schedule … “I’m not in a hurry.”
Initially, there were many views that the re-launch date would exceed the preliminary period of 23 days. The background to the question raised over the launch schedule on the 21st was that the Ministry of Science and ICT and Information and Communication Technology and Kouken may be forcibly advancing the schedule to meet the preliminary launch date.
“We are not forcibly proceeding to set the preliminary day,” said Ko. “Weather forecasts suggest that the weather at the beginning of next week will be a little better, so we have decided to launch on the 21st.” explained.
Kwon Hyun-jun, a giant public research policy officer of the Ministry of Science and ICT, said, “I was never in a hurry to meet the preliminary day.” We decided that the separation was more risky than the profit, so we checked as much as possible. ”