"Why Did the Previously Fine Sensor Malfunction?"... What Will Happen to Nuriho's 2nd Launch? (Comprehensive)

Anomaly Detected During Pre-Check on the Afternoon of the 15th, One Day Before Launch on the 16th
Oxidizer Tank Charge Measurement Sensor Malfunction,
Lowered from Launch Pad and Transferred to Assembly Building for Detailed Inspection
Future Launch Schedule Uncertain, KAIST "Depends on Severity of Malfunction"
Experts "Common Occurrence, Should Watch Calmly"

[Asia Economy Reporter Kim Bong-su] South Korea's first indigenous space launch vehicle, 'Nuriho,' has failed to take its second step toward completion. Due to an anomaly detected in the measurement sensor, the second launch scheduled for the afternoon of the 16th was canceled and inspection began. Depending on the cause, the launch could resume within a week or be delayed for at least a month, potentially causing significant repercussions. Although there is public criticism, experts advise that since such issues are commonly experienced even by leading space powers worldwide, it is important to remain composed and overcome the challenge.

◇ Halted due to sensor anomaly, cause unknown

On the morning of the 15th, Nuriho was transported to the second launch pad at Naro Space Center in Goheung, Jeollanam-do, and final checks began in the afternoon. However, around 2:05 p.m., the Korea Aerospace Research Institute (KARI) technical team detected an abnormality, triggering an emergency. Although the vehicle was moved lying down and then stood upright, it was confirmed that the measurement value of the oxidizer tank filling sensor did not change and remained constant. Following an urgent inspection, KARI technicians discovered that the sensor was not functioning properly. On-site engineers gathered to determine whether immediate repairs could be made to meet the launch schedule the next day, but concluded that it was impossible while the vehicle was upright. Consequently, KARI held a launch management committee meeting with the Ministry of Science and ICT and decided to first remove Nuriho from the launch pad, transport it to the assembly building, and conduct a detailed inspection.

The cause is estimated to be one of three possibilities: the sensor itself malfunctioning, a broken wire, or a failure in the terminal that collects and displays the information. KARI maintains that the issue can only be identified after disassembly. KARI’s Head of the Korean Launch Vehicle Development Project, Ko Jung-hwan, stated in a briefing shortly after, "Currently, rapid inspection is the most important task," adding, "We need to disassemble and examine the oxidizer tank lid where the valve is installed."

The problem raises questions because this sensor operated normally during the wet dress rehearsal (oxidizer filling and discharge test) conducted before the first launch in October last year, as well as during the first launch itself. KARI described the sensor as a "domestically produced item" but did not disclose the manufacturer’s name. As a result, some criticism has arisen, suggesting insufficient preparation or pre-inspection and exposing technical limitations.

The Korean launch vehicle Nuriho (KSLV-II) stands upright on the launch pad at Naro Space Center in Goheung-gun, Jeollanam-do, one day before its second launch on the 15th. Photo by Joint Press Corps

◇ Future launch schedule shrouded in uncertainty

Nuriho has been removed from the launch pad and transported to the assembly building at Naro Space Center for detailed inspection. The launch scheduled for the afternoon of the 16th was canceled. If the malfunction involves easily replaceable or inspectable components such as wiring or the terminal, the launch might still be possible within the reserved period set until the 24th. However, if the issue requires replacing the sensor and related parts entirely or involves more complex matters, it is expected to take at least a month, inevitably delaying the launch schedule for an extended period. If the launch fails within the reserved period, rescheduling will require coordination and notification among domestic and international agencies, considering weather conditions, space objects, and solar activity, among other controls. Particularly, if the problem is not partial but requires structural improvements, the Nuriho launch could be postponed for a significant time. However, considering that the sensor functioned properly during the first launch, such a possibility is considered low.

Experts advise that since such incidents are common even among the world’s leading space powers and top private companies like SpaceX, the response should be encouragement and support rather than criticism. For example, Brazil developed the VLS space launch vehicle from the 1980s but failed to produce solid motors, resulting in an explosion that killed 21 people, ultimately leading to the project's termination in 2016. The European Union (EU) also abandoned its project after repeated failures in all flight tests of Europa-1 and Europa-2 during the 1960s and 1970s due to errors in the three-stage automatic termination system and fairing separation system. The United States failed in developing the Percheron launch vehicle due to inability to build the oxidizer tank pressurization system, and the Conestoga launch vehicle project was abandoned due to control system development failure. Russia attempted to build the N-I rocket for lunar exploration in response to the US Apollo project but never completed it.

Currently, SpaceX, renowned for its reusable Falcon 9 rocket, faced numerous challenges while developing the Falcon 1 launch vehicle, including issues with the propulsion system and engine vibrations, as well as stage separation failures. Recently, the development of the large Mars exploration launch vehicle 'Starship' has encountered several explosion accidents and other difficulties. Japan struggled with resonance phenomena during the development of the H-II rocket and even experienced an engine explosion accident that resulted in the death of a technician. India also faced difficulties in developing and transferring cryogenic engine technology while developing the GSLV rocket. Recently, on the 12th, the US private space company Astra launched Rocket 3.3 carrying small satellites for NASA, but the rocket failed to enter orbit due to anomalies immediately after stage 1 and 2 separation.

Lee Chun-geun, Honorary Research Fellow at the Korea Institute of Science and Technology Policy, said, "This is a problem frequently encountered even by so-called space powers and is entirely surmountable. In fact, discovering the issue before launch is a positive outcome. Rather than criticism, it would be better to encourage and calmly observe the situation."

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