Nuriho 2nd Launch Halted Due to Sensor Failure... Quick Resumption Uncertain (Comprehensive)

Abnormal Operation of Oxidizer Tank Filling Level Sensor at Stage 1
Currently Moved from Launch Pad to Assembly Building
KARI "Inspection Needed to Gauge Quick Resumption"

On the 15th, one day before the second launch of the Korean launch vehicle Nuri (KSLV-II), Nuri is being erected on the launch pad at Naro Space Center in Goheung-gun, Jeollanam-do. Photo by Korea Aerospace Research Institute

[Asia Economy Reporter Kim Bong-su] The second launch of Nuriho, Korea's first indigenous space launch vehicle, was halted due to a sensor malfunction. Depending on the inspection results, it is still uncertain whether the launch will resume soon or if the date will need to be rescheduled.

The Ministry of Science and ICT and the Korea Aerospace Research Institute (KARI) announced on the 15th around 5 p.m. that the Launch Management Committee had made this decision. The cause was an abnormality in the sensor of the oxidizer tank in the first stage. According to KARI, around 2:05 p.m. on the same day, during the final inspection after the Nuriho launch vehicle was erected on the launch pad, a malfunction was confirmed in the sensor measuring the fill level of the oxidizer tank. If this sensor malfunctions, it is impossible to accurately check the tank status when filling liquid oxygen on the launch day.

KARI technicians initially attempted to repair the malfunction on-site but confirmed that it was impossible. Accordingly, around 5 p.m., the Launch Management Committee decided to lower Nuriho from the launch pad and transport it to the assembly building for detailed inspection and repair. As a result, Nuriho is currently being moved from the launch pad to the assembly building, and the launch scheduled for the 16th has been canceled.

It is still uncertain when the launch procedures will resume. KARI stated that they need to disassemble the launch vehicle in the assembly building for a detailed inspection to determine the extent of repairs and the time required.

Ko Jeong-hwan, Head of KARI's Korean Launch Vehicle Development Division, said, "At this point, the top priority is to inspect as quickly as possible to identify the problem," adding, "It is difficult to say when the launch schedule will be rescheduled."

Below is a Q&A with Head Ko and KARI Director Lee Sang-ryul:

- How will the launch schedule change?

△ It depends on which part is malfunctioning. Currently, we do not know which part is the problem. We need to analyze to know clearly. It is necessary to transport it as soon as possible for inspection.

- Can it be done within the reserved launch dates?

△ There are spare sensors and electrical harnesses. It is necessary to quickly identify the cause. The schedule will be set accordingly. We plan to continue inspections and confirmations.

- When, how, and why did the problem occur?

△ We completed inspections of electrical equipment and sensors during assembly. Afterwards, the stage integration and launch preparations proceeded without issues.

- What problems arise if the oxidizer fill level sensor malfunctions?

△ Other electrical inspections showed no abnormalities, but only one sensor showed unusual values. Work stopped at that point. Attempts to identify the cause on-site were unsuccessful.

- What is believed to be the cause?

△ The sensor itself may be faulty, or the cable might be defective, or the terminal (signal converter) could be malfunctioning. If it does not operate properly, it is difficult to measure how much oxidizer is loaded. In the first launch, the oxidizer tank issue was mechanical, but this sensor malfunction appears to be electrical. The oxidizer is in an extremely low temperature state at minus 183 degrees Celsius, so it is not a simple sensor. This was an unforeseen problem during the first launch.

- How extensive are the repairs needed?

△ Physically replacing the sensor requires removing it from the oxidizer tank lid. However, if the problem is with electrical connection lines or the terminal box, only the affected parts need to be replaced. The speed of repair depends on which parts are problematic and how.

- Is a launch tomorrow impossible?

△ The vehicle that was erected is being laid down and transported to the assembly building. A launch tomorrow is difficult. The top priority is to inspect as soon as possible. Until the inspection is complete and the problematic parts are identified, it is difficult to provide a schedule. If it cannot be done within the reserved dates (17th to 23rd), the process will be repeated to notify the international community and set a new launch date. Internally, the repairs will be reviewed, confirmed, and verified, then the Launch Management Committee will convene to set the next launch schedule.

- How do you feel currently?

△ We are embarrassed and sorry that this happened. We will do everything possible to solve the problem and make a sure fix to try again.

- Was the wet dress rehearsal conducted?

△ It was conducted during the first launch since it was the first time. It is done to check for issues during oxidizer filling and venting. This time, based on internal review, it was decided not to conduct it because it would take a lot of time and could strain the vehicle. The issue today occurred before oxidizer filling. The problem may be a simple hardware issue rather than a fundamental one.

- Could internal payloads such as CubeSats be affected by long-term storage?

△ If done quickly, there is no problem. If delayed, the vehicle can be lowered and moved to the preparation building for storage.

- Does this kind of issue happen often?

△ Even overseas, there are frequent cases where launches are stopped or delayed due to sensor errors related to liquid oxygen during launch vehicle preparation.

This content was produced with the assistance of AI translation services.