Smooth Launch of Naro-1 Expected Wednesday

Will the domestically developed space launch vehicle Naro-1 successfully blast off Wednesday?

The Korea Aerospace Research Institute says the launch of the Naro-1, also called Korea Space Launch Vehicle-1 (KSLV-1), in August last year was successful except for the separation of a fairing that protected the satellite it carried.

Success of the launch will depend on a host of factors.

□ Successful operation of the first and second stage rockets

From 1957 through 2003, 198 rocket launches failed worldwide. Of them, 131 (66.2 percent) were due to engine failure.

For the Naro-1 to be successfully launched, the most critical factor is perfect operation of the first- and second-stage engines. The Naro-1 has a first-stage liquid engine imported from Russia and a second-stage solid engine developed domestically.

The performance of the first-stage engine was proven in last year’s launch. Yoon Ung-seop, a mechanical engineering professor at Yonsei University, said, “The first-stage engine of the Naro-1 is the same kind as that of Russia’s next-generation rocket Angara, which Moscow began developing from 1991,” adding, “Its performance and stability are so excellent, it can replace the Soyuz.”

The possibility of engine explosion is low, but such a danger cannot be ignored in determining a successful launch.

Most experts agree that the second-stage rocket will perform well. Korea developed a rocket using solid fuel in the 1970s. The KSR-I launched 1993 and KSR-II launched in 1997 were capable of sending an object weighing 10 tons into space, so no problem will arise since the Naro-1’s second-stage rocket must send a satellite weighing only seven tons.

□ Separation of fairings

Whether fairings will be separated from the rocket is getting the most attention. In the first stage of the launch last year, one of the two fairings fell off from the rocket 216 seconds after launch, but the other separated 264 seconds afterwards.

Because of this, the flying of the second-stage rocket was unstable because it still carried the fairing weighing 330 kilograms. As a result, the rocket failed to reach the targeted orbit of 306 kilometers above the earth.

The separation of fairings happens through electrical signals. If a special volt explodes, fairings are separated just as springs jump out. If electrical signals are weak, the volt will not explode and fairings will not be separated.

□ Timing of the separation of the first-stage rocket from the second

The separation of the first-stage rocket from the second will also affect the success of the launch. When the first-stage engine stops and the four explosion volts connecting the first and the second rockets go off, the two rockets will be separated. The separation should happen within 0.5 microseconds for the second-state rocket to enter orbit.

Roh Tae-seong, a mechanical aerospace engineering professor at Inha University, said, “When the first-stage rocket is separated from the second, the Naro-1 will be flying faster than the speed of sound,” adding, “The risk is high since the separation must come in an unstable environment.”

The separation of the second-stage rocket from the satellite should be successful since it happens after the rocket enters orbit.

□ Software malfunction

Other factors to affect the launch include the flying of the Naro-1 and the operation of systems, such as devices used for guidance control and internal assessment. System failures will lead to irregular flying of the launch vehicle.

The European space launch vehicle Ariane 5 went out of its trajectory at an altitude of four kilometers due to failure of internal programs.

Professor Yoon said, “The performance of the domestically developed launch control program was proven in the first launch attempt last year,” adding, “The mock environment is not that different from the actual flying environment, so no problems will arise.”

□ Weather

There is virtually no possibility of the Naro-1 being struck by lightning and going off in midair. The Korea Meteorological Administration said the possibility of showers and lightning is very low Wednesday because of the stable atmosphere.

Gong Chang-deok, an aerospace engineering professor at Chosun University, said, “The weather on launch day for the Naro-1 will be fine, so risk stemming from weather will be low,” adding, “The launch will be a success because last year’s launch was half successful and weak elements were improved.”

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