Fairing assembly cited for 'half successful' space rocket launch

(ATTN: UPDATES with more details, comments throughout)
SEOUL, Feb. 8 (Yonhap) -- An independent private panel on Monday cited problems
in the fairing assembly of South Korea's first space rocket as having caused the
"half successful" launch that failed to place a satellite into orbit last year.
The 10-person panel, headed by Lee In, an aerospace engineering professor at the
Korea Advanced Institute of Science and Technology (KAIST), said its
investigations indicated that faulty electrical wiring or a structural problem in
the fairing assembly's separation explosive mechanism were the likely causes
behind the Aug. 25 mishap.
The Korea Space Launch Vehicle-1 (KSLV-1) blasted off successfully from the Naro
Space Center 485 kilometers south of Seoul, but one of two fairings failed to
detach during the ascent stage. The added weight of the fairing made it
impossible for the two-stage rocket to reach proper velocity to deploy the 100
kilogram scientific satellite.
The KSLV-1 also called the Naro-1 is South Korea's first locally assembled and
launched space rocket.
"The probe has narrowed down the cause to faulty electrical discharge in the
Fairing Separation Driving Unit wiring that prevented the explosives from going
off 216 seconds into the flight or a structural problem that held the 'near'
fairing in place despite the explosives taking place at the pre-set time," the
professor said.
He added that careful examination of telemetry sent back from the rocket
indicated that the fairing that did not eject properly actually collided with the
satellite as it separated from the rocket 540 seconds after liftoff.
"We had checked other possible causes such as substandard explosives, but reached
the conclusion such developments were unlikely," the KAIST expert said.
Lee said that the findings had been forwarded by the Failure Review Board (FRB)
to Russia's Khrunichev State Research and Production Space Center that jointly
built the rocket. The FRB made up of South Korean and Russian experts have been
examining details of the launch separate from the panel.
"The Russian side did not raise any objections to the conclusions reached," he said.
The panel in cooperation with Korea Aerospace Research Institute (KARI) had
checked 5,200 documents, conducted 30 rounds comprehensive systems checks and
carried out hundreds of evaluations on individual parts.
It said that although one fairing failed to come off all other systems like the
ignition of the second kick motor rocket occurred without a hitch.
KARI and the science ministry said all problems discovered will be resolved in
the second Naro-1 rocket scheduled for the first half of this year so another
mishap does not take place.
"Engineers are in the process of exchanging the electrical wiring and building
new backup systems to make certain that if the explosives go off the fairings
will be jettisoned," said Cho Gwang-rae, a senior researcher of rocket
development at KARI.
He said the state-run institute started to implement lessons learned in the
investigations and plans to conduct numerous tests on the modifications.
Cho, however, said that because the country had never launched a space rocket on
its own and did not have a lot of experience, it had used foreign-made launch and
testing manuals that may not have allowed more pre-launch testing of all systems.
"He said that local engineers had not prepared fully for the very low vacuum
conditions that may have caused electrical system to fail," the expert said.
The ministry in charge of the rocket program said that with upgrades underway
with the fairing assembly unit, the second Naro-1 launch should take place as
scheduled in May or early June.
Khrunichev is expected to send the first stage main booster rocket around March
for assembly with the second stage rocket and satellite made in the country.
Local engineers have also started to check the launch pad and other support
systems as of Monday last week.
South Korea spent 502.5 billion won (US$428.5 million) to develop the 140 ton
rocket that stands 33 meters tall with a diameter of 2.9 meters.
The government and KARI, meanwhile, said that it is not currently discussing the
possibility of asking its Russian partner for a third launch, since it wants to
focus on Naro-1's upcoming launch.
"Once this is concluded, the two sides can decide to consider a third launch," a
sources said.
Under the original cooperative pact, the two sides can call for another launch if
there are problems in the two planned launches.
yonngong@yna.co.kr
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