ID :
76741
Mon, 08/24/2009 - 17:30
Auther :
Shortlink :
https://oananews.org//node/76741
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 determined within the minute after liftoff, local experts said Monday.
Engineers and government officials said the critical stage of the liftoff of the
Korea Space Launch Vehicle-1 (KSLV-1), set for Tuesday, will be during the
initial ascent from the Naro Space Center, located 485km south of Seoul.
"Initially, the rocket will be moving relatively slowly, making it hard to
maintain stability as the main engine tries to push up the 140t 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 the 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 the time, the Naro-1 will be 7.4km from the ground and heading in a southerly
direction, with the Russian-made first stage rocket providing 170t 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, 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, roughly 900m above the launch pad.
The maneuver is designed to steer the rocket south to place the scientific
satellite into orbit while not passing over populated areas during the rest of
its flight.
The director said if the Naro-1 fails to make the turn and takes an unauthorized
trajectory, ground controllers will destroy it by remote control.
"The turn must be precise and 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 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 failing
to reach proper altitude, which is 300km or more from the Earth's surface.
The last challenge is expected 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 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.
The Korea Advanced Institute of Science and Technology, which made the satellite,
said not making contact on the first attempt would not signify failure, as long
as the satellite deploys its solar panels and generates power.
"As long as the satellite is generating power, contact can be made at a later
date if its exact location is known," a research 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 to
conduct experiments properly.
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.
A source in the Ministry of Education, Science and Technology in change of the
country's space exploration project, meanwhile, said if the launch is postponed
once again due to technical issues, there is a chance Naro-1's liftoff will have
to be pushed back several weeks.
"Seoul will have to notify both the International Civil Aviation Organization and
the International Maritime Organization to get new launch dates, which can take
up to eight days," said an official, who declined to be identified.
The two organizations need to be notified so boats and commercial aircraft
operating in the trajectory of the rocket can be warned in advance.
He added that if the launch is delayed again due to a technical problem, local
experts may have to conduct an overall assessment of the launch and related
mechanical systems with their Russian counterparts.
"Public opinion may call for a more detailed assessment of the program, making it
necessary to take a more measured approach," he said.
yonngong@yna.co.kr
NARO SPACE CENTER, South Korea, Aug. 24 (Yonhap) -- The success or failure of South Korea's first rocket will largely be determined within the minute after liftoff, local experts said Monday.
Engineers and government officials said the critical stage of the liftoff of the
Korea Space Launch Vehicle-1 (KSLV-1), set for Tuesday, will be during the
initial ascent from the Naro Space Center, located 485km south of Seoul.
"Initially, the rocket will be moving relatively slowly, making it hard to
maintain stability as the main engine tries to push up the 140t 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 the 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 the time, the Naro-1 will be 7.4km from the ground and heading in a southerly
direction, with the Russian-made first stage rocket providing 170t 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, 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, roughly 900m above the launch pad.
The maneuver is designed to steer the rocket south to place the scientific
satellite into orbit while not passing over populated areas during the rest of
its flight.
The director said if the Naro-1 fails to make the turn and takes an unauthorized
trajectory, ground controllers will destroy it by remote control.
"The turn must be precise and 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 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 failing
to reach proper altitude, which is 300km or more from the Earth's surface.
The last challenge is expected 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 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.
The Korea Advanced Institute of Science and Technology, which made the satellite,
said not making contact on the first attempt would not signify failure, as long
as the satellite deploys its solar panels and generates power.
"As long as the satellite is generating power, contact can be made at a later
date if its exact location is known," a research 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 to
conduct experiments properly.
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.
A source in the Ministry of Education, Science and Technology in change of the
country's space exploration project, meanwhile, said if the launch is postponed
once again due to technical issues, there is a chance Naro-1's liftoff will have
to be pushed back several weeks.
"Seoul will have to notify both the International Civil Aviation Organization and
the International Maritime Organization to get new launch dates, which can take
up to eight days," said an official, who declined to be identified.
The two organizations need to be notified so boats and commercial aircraft
operating in the trajectory of the rocket can be warned in advance.
He added that if the launch is delayed again due to a technical problem, local
experts may have to conduct an overall assessment of the launch and related
mechanical systems with their Russian counterparts.
"Public opinion may call for a more detailed assessment of the program, making it
necessary to take a more measured approach," he said.
yonngong@yna.co.kr
