ID :
76672
Mon, 08/24/2009 - 11:06
Auther :
Shortlink :
https://www.oananews.org//node/76672
The shortlink copeid
First minute after liftoff to decide KSLV-1 success: experts
By Lee Joon-seung
NARO SPACE CENTER, South Korea, Aug. 24 (Yonhap) -- The success or failure of
South Korea's first rocket will largely be decided within a minute after liftoff,
local experts said Monday.
Engineers and government officials said that the critical stage of the liftoff
set for Tuesday will be when the Korea Space Launch Vehicle-1 (KSLV-1) makes its
initial ascent from the Naro Space Center 485km south of Seoul.
"At this phase the rocket is moving relatively slowly, making it hard to maintain
stability as the main engine tries to push up the 140 ton launch vehicle and
satellite payload," said Min Kyung-ju, director of the space center.
"If there is a sudden gust of strong wind or any other slight problem in the
stabilization mechanism, the rocket can tip over and be lost," he said.
The aerospace engineers said the KSLV-1, also called Naro-1, will become more
stable as it gains speed, and that after overcoming the stress of exceeding the
speed of sound 55 seconds after blastoff there is less chance of it crashing to
Earth.
At this time, the Naro-1 would be 7.4km from the ground and heading in a
southerly direction, with the Russian-made first stage rocket providing 170 tons
of thrust.
Lee pointed out that many rockets have been lost during the critical initial
ascent stage, saying that the U.S.-made Vanguard and Atlas G, Europe's Ariane 5
and several other launch vehicles from countries such as China and Russia were
all lost within a minute of liftoff.
South Korea, with no experience of its own in building powerful rockets, had
teamed up with Russia to design and build the rocket.
In addition to the need to pick up speed, the Naro-1 is programed to make a
"kick-turn" maneuver 10 seconds after takeoff and roughly 900m above the launch
pad.
The maneuver is designed to steer the rocket south and in position to place the
scientific satellite into proper orbit while not passing over populated areas
during the rest of its flight.
The director said that if the Naro-1 fails to make the turn and heads in an
unauthorized trajectory, ground controllers will destroy it by remote control.
"The turn must be precise and be carried out at a time when the rocket is not
moving very fast making it very tricky," he said.
Others like Deputy Science and Technology Minister Lee Sang-mok, said the success
of the satellite mission will also depend on the proper release of the fairings
housing the payload, the separation of the first and second stage rockets and the
ignition of the second-stage solid fuel rocket.
The official said if the fairings are not ejected 245km from the launch pad at an
altitude of 177km, the satellite cannot deploy in orbit and the mission will not
be a complete success.
The fairing assembly was made in South Korea and has never been tested in flight.
Another critical moment is expected to come when the first stage main booster is
turned off and separates from the second stage rocket at an altitude of 196km,
with the first stage rocket made in Russia falling to the ocean.
Failure to separate 232 seconds into the flight can result in the rocket crashing
as it will be unable to reach orbit.
The last challenge may come when the locally made second stage rocket's kick
motor has to be ignited over a 1,000km from the Naro center and 395 seconds after
liftoff.
"If the kick-motor functions properly, there is a good chance of the scientific
satellite reaching orbit," Lee said.
Engineers said that if this phase is reached the mission can be considered as
being 90 percent successful.
Once the satellite is deployed, South Korean controllers will determine its exact
altitude and trajectory. They will try to make contact 13 hours after liftoff.
"It would be best if first contact is made on the first attempt, but if the
satellite has deployed its solar panels and is generating power, contact can be
made at a later date once its location is known," a working government official
said.
The small 100kg scientific satellite does not have the ability to correct its
course so it is important for it to have reached its proper trajectory if it
wants to conduct its experiments properly. These include checking the atmosphere
and exact distance of the satellite form the ground.
If contact is made, South Korea will become the world's 10th country to
successfully send a locally developed scientific satellite into orbit from its
own soil.
South Korea spent 502.5 billion won (US$402.3 million) on the Naro-1, which
stands 33m tall and has a diameter of 2.9m. It spent 13.6 billion won on the
satellite.
yonngong@yna.co.kr
(END)
NARO SPACE CENTER, South Korea, Aug. 24 (Yonhap) -- The success or failure of
South Korea's first rocket will largely be decided within a minute after liftoff,
local experts said Monday.
Engineers and government officials said that the critical stage of the liftoff
set for Tuesday will be when the Korea Space Launch Vehicle-1 (KSLV-1) makes its
initial ascent from the Naro Space Center 485km south of Seoul.
"At this phase the rocket is moving relatively slowly, making it hard to maintain
stability as the main engine tries to push up the 140 ton launch vehicle and
satellite payload," said Min Kyung-ju, director of the space center.
"If there is a sudden gust of strong wind or any other slight problem in the
stabilization mechanism, the rocket can tip over and be lost," he said.
The aerospace engineers said the KSLV-1, also called Naro-1, will become more
stable as it gains speed, and that after overcoming the stress of exceeding the
speed of sound 55 seconds after blastoff there is less chance of it crashing to
Earth.
At this time, the Naro-1 would be 7.4km from the ground and heading in a
southerly direction, with the Russian-made first stage rocket providing 170 tons
of thrust.
Lee pointed out that many rockets have been lost during the critical initial
ascent stage, saying that the U.S.-made Vanguard and Atlas G, Europe's Ariane 5
and several other launch vehicles from countries such as China and Russia were
all lost within a minute of liftoff.
South Korea, with no experience of its own in building powerful rockets, had
teamed up with Russia to design and build the rocket.
In addition to the need to pick up speed, the Naro-1 is programed to make a
"kick-turn" maneuver 10 seconds after takeoff and roughly 900m above the launch
pad.
The maneuver is designed to steer the rocket south and in position to place the
scientific satellite into proper orbit while not passing over populated areas
during the rest of its flight.
The director said that if the Naro-1 fails to make the turn and heads in an
unauthorized trajectory, ground controllers will destroy it by remote control.
"The turn must be precise and be carried out at a time when the rocket is not
moving very fast making it very tricky," he said.
Others like Deputy Science and Technology Minister Lee Sang-mok, said the success
of the satellite mission will also depend on the proper release of the fairings
housing the payload, the separation of the first and second stage rockets and the
ignition of the second-stage solid fuel rocket.
The official said if the fairings are not ejected 245km from the launch pad at an
altitude of 177km, the satellite cannot deploy in orbit and the mission will not
be a complete success.
The fairing assembly was made in South Korea and has never been tested in flight.
Another critical moment is expected to come when the first stage main booster is
turned off and separates from the second stage rocket at an altitude of 196km,
with the first stage rocket made in Russia falling to the ocean.
Failure to separate 232 seconds into the flight can result in the rocket crashing
as it will be unable to reach orbit.
The last challenge may come when the locally made second stage rocket's kick
motor has to be ignited over a 1,000km from the Naro center and 395 seconds after
liftoff.
"If the kick-motor functions properly, there is a good chance of the scientific
satellite reaching orbit," Lee said.
Engineers said that if this phase is reached the mission can be considered as
being 90 percent successful.
Once the satellite is deployed, South Korean controllers will determine its exact
altitude and trajectory. They will try to make contact 13 hours after liftoff.
"It would be best if first contact is made on the first attempt, but if the
satellite has deployed its solar panels and is generating power, contact can be
made at a later date once its location is known," a working government official
said.
The small 100kg scientific satellite does not have the ability to correct its
course so it is important for it to have reached its proper trajectory if it
wants to conduct its experiments properly. These include checking the atmosphere
and exact distance of the satellite form the ground.
If contact is made, South Korea will become the world's 10th country to
successfully send a locally developed scientific satellite into orbit from its
own soil.
South Korea spent 502.5 billion won (US$402.3 million) on the Naro-1, which
stands 33m tall and has a diameter of 2.9m. It spent 13.6 billion won on the
satellite.
yonngong@yna.co.kr
(END)
