Nuri went up to the target height yesterday (21st), but it was not able to put the model satellite it was carrying into normal orbit. This is because the three-stage engine at the top of the projectile was turned off earlier than expected, and various analyzes are coming out as to the reason.

First, reporter Jung Gu-hee reports.


Launch and initial flight were stable.

The 300-ton main engine raised the Nuri to the sky with sparks, and the process that was considered as a turning point, such as separating the first and second stages and fairing, was successfully passed.

However, a problem arose when it reached the target altitude about 15 minutes after launch.

The three-stage engine at the top of the Nuri was turned off earlier than expected, and the isolated model satellite failed to orbit the Earth and crashed at a reduced speed.

[Koh Jung-hwan / Head of Anti-accidental Launch Vehicle Development Division: We last measured it as it fell into the southern sea of ​​Australia, but we are going to check that part by further analyzing the measurement data.] The

satellite is In order to orbit the Earth uniformly, the centrifugal force to fly into space must be the same.

To achieve this centrifugal force, the satellite must travel at 7.5 km/s.

However, the 3-speed engine burns for 521 seconds to increase the speed, but it was turned off 46 seconds quickly and did not reach its speed.

The Korea Aerospace Research Institute is considering three possibilities, considering that it is not a problem with the engine itself.

The third stage consists of a 7-ton liquid engine, a fuel tank, an oxidant tank, and a model satellite at the top.

We are looking into the possibility that the oxidizer and fuel supply was not working properly due to insufficient pressure in the tank, the fuel and oxidizer supply valves are malfunctioning, and the electronic control equipment may malfunction.

In the midst of this, the government decided to form a launch investigation committee with external experts to help the second launch in May next year.

(Video editing: Jeon Min-gyu, CG: Seo Seung-hyun)    

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Keywords: engine, top, orbit, launch, engine combustion, cause, nuri, model satellite, thesatellite, target height, projectile, effort, process, nuri-ho, problem