Space

KSLV - Korean Space Launch Vehicle-1 Second Flight

The Korea Aerospace Research Institute (KARI) Russian made Ground Test Vehicle with The Republic of Korea second stage and payload shroud undergoing launch pad installation facilities testing April 15, 2009

Republic of Korea [ROK] KSLV-1 Second Launch, Scheduled Between June 9, 2010 & June 19, 2010 , A Failure

The launch of KSLV-1 number 2 is scheduled between 16:30 and 18.40 [ 4:30 PM & 6:40 PM ] launch local South Korean time. The flight hardware was moved to the launch pad from the booster assembly building two days prior to for its first launch attempt once flight readiness was established from the flight readiness review. This most basic data has also been shared with the International Civil Aviation Organization along with the International Maritime Organization as a preliminary warning notification to ships and aircraft. The expected impact point for the first stage has also been identified.

Range calibration readiness testing was started during the week of May 9-16, 2010 . Using a small aircraft over two hours to test simulate the flight path, various down-range and safety systems for testing the telemetry signals, communications, radar, optical tracking capabilities. By Monday May 19, 2009 the two stage KSLV-1 (Naro-1) along with its STSAT-2B (Science and Technology Satellite) and two piece shroud had been completed. This was followed by the battery of electronic systems tests to assure that all systems operate as one system before final prepping for rollout to the pad. Roll out is not expected until two days prior to the launch attempt. Through June 4, 2010 the comprehensive testing by both South Korean and Russian engineers on the readiness for rollout of the KSLV-1 was in progress.

KSLV-1 with its STSAT-2B satellite 100 kilogram payload was scheduled for roll out from its assembly building on its erector transporter on Monday morning June 7th around 8:15 a.m. South Korean time. That normally takes about 90 minutes after an approximately 1 kilometer trip. The journey in fact took one hour and 20 minutes. Its booster and payload were to be erected onto and fastened to the pad after ground connection testing during the 4 - 5 P.M. period with the finish up work going into the evening hours. During that check up process of the launch vehicle on the pad emitted "unstable electronic signals detected through the Ground Measurement System (GMS)" from the rocket pad and umbilical mast cabling connections causing a considerable delay in the final pad installation. GMS is an automated ground launch vehicle electronic check out system designed to warn of technical problems in the readiness status of the launch vehicle and ground support systems compatibility for flight. As an example this system would quickly identify potential short circuits in these systems. Further testing will be required to make sure it is not a launch vehicle related issue but cable or pad systems and or umbilical mast related installation issue. Thus the KSLV-1 was erected on to the pad later in the evening with the umbilical mast still not connected but the kerosene and liquid oxygen lines were connected to the booster and the launch azimuth alignment calibration and diagnostic work was completed. At this writing the cause of the issues had not been identified but was said to have been corrected. Until that issue is resolved to all involved satisfaction the planned June 9, 2010 launch between 4:30 pm. and 6:40 pm. South Korean time remains in question.

The final launch demonstration countdown was scheduled for Tuesday June 8, 2010 if the unstable electronic signals issue is resolved but it was expected to delay this planned launch scheduled between June 9th and the June 19, 2019 in the review meeting scheduled for Tuesday morning. That review ultimately cleared the technical issues.

Reconnection of the umbilical mast connectors was successfully conducted and the launch commission made up of Governments officials and specialist approved going forward with the about six hour long subsequent demonstration countdown and simulated flight. Six hours were required for the first stage while four hours were required for the second stage and payload. This confirmed the readiness of the total launch infrastructure including the range, pad and booster, satellite combination for the flight planned for the late afternoon of June 9, 2010 . The final go no go launch decision to enter the final countdown will come at between 1-1:30 p.m. local South Korean time on June 9, 2010.

On June 9, 2010 launch day at 1:58 P.M. about three hours prior to the intended 5 P.M. launch the countdown was scrubbed due to the premature release of fire abatement retardant fluids and gases near the launch vehicle from three fire extinguisher nozzles. This premature release was caused by an electrical system malfunction in the fire retardant system. The ensuing investigation isolated the problem and established that none of the products got to the launch vehicle or other pad equipment. With this conclusion to this issue the launch was rescheduled for June 10, 2010 between 4:30 pm. and 6:40 pm with the actual launch attempt later scheduled for around 5 p.m. South Korean time.

The June 10, 2010 launch day was finally confirmed about 1:30 p.m. South Korean time and all seemed to go well through liftoff at 5:10 p.m. The launch programming was much smoother going to pitch over to get away from above the pad area as well as with the roll and pitch over to go down range after 20 seconds of near vertical flight about 900 feet in altitude . The launch vehicle with its payload survived Max-Q maximum dynamic pressure at about 50-55 seconds into the flight.

Quite unexpectedly at 137 seconds into flight the launch vehicle carrying the earth observation satellite flashed at a high altitude of about 70 kilometers some 87 kilometers down range in an explosion terminating the flight that outwardly had appeared to be a good flight performance. At that very point the telemetry communications dropped out as the flash was observed by the second stage downward facing camera. Where the flash came from is unclear based on what has been released by South Korea . Review of the flight telemetry up to the 137 seconds of flight show no anomalies according to South Korean officials. The vehicles broken up state after the explosion caused the debris to impact some 470 kilometers down range in the 30 degrees north latitude and 128 degrees east longitude south of Jeju Island with South Korean naval ships recovering the floating debris. Ocean floor recovery of the remaining debris may be possible in due course.

What Went Wrong Is a Very Large Question Indeed.

One could wonder whether the emitted "unstable electronic signals detected through the Ground Measurement System (GMS)" might have been launch vehicle wiring or a short circuit related issue that only occasionally showed itself until flight if then.

Just prior or immediately after the initial explosion around 137 seconds the vehicle is said to have veered off course but this is not officially confirmed with any detail. Subsequently it is indicated that there may have been a second explosion at 0.5 second followed by a third at 5 or 10 seconds later. The initial explosion is unquestioned but knowing how kerosene lox engines perform as they gain altitude you do see the flame colors change to an orange, red like coloration and finally in space to almost white color instead of the hot yellow clearer colors of launch. So the open interpretations of this imagery remains suspect at this early juncture of the commissions closed analysis. Though NPO Energomash, Russian technicians and engineer say the RD-151 engine performed nominally though that too remains suspect. What was the status of the in flight destruct system in the last seconds of the flight is also an issue not discussed for potential software or wiring errors.

Initial emphasis on the probable failure of the RD-151 closed cycle Russian, NPO Energomash first stage engine was one of two major suggestions for the loss. Under that scenario the RD-151 engine might have lost control of the Oxidizer, Fuel mixture ratio causing the engine to literally melt itself down to explosion and loss of thrust which this engine has been know to do in the test stand. Again this is not officially confirmed from the available information. The in flight second stage flight control system of South Korea was not active at this point in flight as confirmed by the Korea Aerospace Research Institute (KARI).

The second major suggestion was that the second stage of the KSLV-1 was some how triggered into a premature staging from the first stage causing a collision of the two but this is not confirmed. The second stage motor did not fire. Ground based imagery released does suggest that after the explosion the second stage and first stage did separate intact but that does not confirm this suggestion. In fact the Korea Aerospace Research Institute (KARI) confirmed based both on imagery and telemetry that there was no premature staging or shroud fairing separation. The entire second stage package, payload and shroud remained intact .

In all cases what is suggested and seen generally does not indicate the root cause of the failure. Certainly the seemingly shaky build up to this launch attempt seems to suggest a rushed management effort under political pressure had introduced itself strongly implying that a “stand down” was absolutely required. With one Russian software engineer trying to commit suicide gives some indication of the pressure that was obvious through out this entire build up process. Yes the flight programming software should be thoroughly reviewed for errors. It should not have been launched in order to totally re-review all the systems and the issues not seen before during this build up effort. Considerable pad time analysis with 130 tonnes of propellant loading and unloading systems testing and perhaps a test firing of the first stage should have been done during such a “stand down”.

A third launch of the KSLV-1 launch vehicle is assured because of the original contract language guaranteeing a third launch if any of the first two launch attempts fail. That pending decision will depend upon the joint commission’s review of the root cause of this launch failure. South Korea through this flight attempt will have spent about $405.8 - $410.8 million dollars or about 502.5 billion Won since 2002 on this program with major commercial assistance from Russia . If South Korea had been successful with the launch it would have become the 10th nation to launch its own satellite from its own territory on its domestically developed infrastructure and launch vehicle.

Launch Events 9- Minute of Flight

A. Engine Start-up ignition and power build up 3.8 seconds before liftoff.

1. Lift off between 16:30 and 18.40 [ 4:30 PM & 6:40 PM ] launch local South Korean time. Riding on a 170 metric tons thrust with a liftoff mass of 140 metric tons gives it a lift off thrust to weight ration of approximately 1.2 gee's acceleration.

2. After 20 seconds of vertical flight about 900 feet altitude above the pad the steering command from the flight program will guild the booster pitching it down range to its launch azimuth inclination planned.

3. The KSLV-1 booster will endure its Max-Q maximum dynamic pressure at about 55 seconds into the first stage powered flight.

4. Some 215 seconds after lift off the payload shrouds are to be explosively jettisoned to re-enter the earth atmosphere at a range of 245 kilometers from the point of origin with an altitude of 177 kilometers.

5. First stage shut down comes some 228 seconds after launch with the second stage and payload some 316 kilometers from the pad with an altitude about 196 kilometers. The first stage will reenter the atmosphere near its impact point near the Philippines ’ trench next to the Philippines.

6. Ignition of the second stage "Kick motor" is to take place at an altitude of 303 kilometers with a range of 1,052 kilometers from the pad.

7. The "Kick Stage" burns out at 453 second after launch with an orbital altitude of 304 kilometers.

8. After 9 minute (540 seconds) the STSAT-2 is separated placing it in orbit at approximately 302 kilometers altitude.

Corrective Action Post First Flight Attempt

From the apparent reasons of the launch failure of KSLV-1 the South Korean's have taken actions to prevent the electrical and or mechanical failure. This has resulted in a duplicate shroud separation system as well as the use of cables with greater resistance and the molding of those wires connected to the trigger that separates systems for the fairing. If part of the shroud fails to separate properly and back up system will assure its proper separation with each half's separation cross check of the others operation. It is the improper separation of one of the two piece shrouds that is blamed for the failure to successfully place the satellite in orbit during the August 2009 attempt.

If all had gone well with the KSLV-1 (1) first launch a second launch with a STSAT-3 satellite was tentatively scheduled for April 2010 with a third launch vehicle being prepared as a back up in case of a launch loss in the first two of the series. South Korea has already placed 10 satellites in orbit cooperating with other countries in addition to having its first astronaut placed in space in April 2008.