(TD-2) Second Flight Test
DPRK Third Satellite Launch Attempt Unha-2/Taep'o-dong-2 second Flight Test Performance
© By Charles P. Vick (All Rights Reserved)
Senior Technical Analyst, Globalsecurity.org
4-29-09 — 07-04-09
Unha-2/Taep’o-dong-2B ballistic missile, space booster
What follows is a preliminary analysis of the second flight test of the three stage Unha-2/Taep’o-dong-2 ballistic missile, space booster based on the intelligence information released from authorized South Korean, Japanese and US intelligence sources without attribution. The addition of the all sources open source imagery, video and open source published information has allowed a cross check of the information in considerable detail via original sources and direct reporter discussions for mutual clarifications.
Unha-2 Booster Range Performance Details
The first stage performed as planned quite cleanly impacting about 280 km or [320 km] from Japan’s northern mainland island at 11:37 am. The No-dong-B second stage did stage and separate completing its full throttled burns otherwise it would have collapsed on Japan ’s Northern mainland island. That second stage only went through 1/3 to 1/2 of its burn before it was throttled down. The flight was to take 9 minutes 2 seconds (542 seconds) to get to orbit with about 4 - 2 seconds for first stage start up. If the stages went through were straight burns one right after the other at full power it would have taken less than six minutes to get to orbit. That is a far higher acceleration rate than structurally desirable.
In fact the third stage would have had a coast period in its flight plan of perhaps 120 – 190 - 200 seconds to the perigee height of the trajectory before firing to complete the orbital insertion burning of perhaps 38 seconds estimated.
The second stage like Taep'o-dong-1 Scud-ER second stage used step-throttling operation in its propulsion to stretch the second stage burn to gain first altitude then range and velocity. That is the No-dong-B stage was step throttled during the first third or half of the second stage burn stretching its burn over 180 seconds. It was initially at full power to get altitude then it was to shift to a lower thrust in the vacuum of space of perhaps 65 % stretching out that burn race to orbit beyond 180 seconds but well less than 380 seconds with a third stage coast period of less than 190-200 seconds.
The on board computer separated the payload and third stage shrouds on time and they impacted down range within the planned Pacific Ocean impact zone 2,150 - 2,950 km some 2,300 km from Japan as intended but the second stage and third stage separated on the proper sequence but the third stage did not fire. It has come through from South Korea that indeed the third stage and payload separated on time but the third stage did not perform as it was supposed to.
When studying the launch video at launch at the base of the second and third stages tapered sections at just before and after liftoff revealed the presence of active stage thruster system for yaw, pit, roll, and translation control never seen before. What is eye opening is that the third stage set of reaction control system (RCS) thrusters that are visible did not fire visibly prior to launch indicating to me that the third stage went dead even before launch. The payload went down with the third stage. The second stage apparently performed properly through its burn before separation. The second stage and third stage and payload began to go ballistic after the second stage burn and separation and lost velocity falling back to earth. Before the reentry started the second and third stages separated on time as planned.
That is the shroud surrounds the third stage and payload and its elements impacted 2,300 km from Japan while the second and third stage impacted 2,330 km from Japan . That is shroud impact was 3,200 km from launch pad and second and third stages impact was 3,230 km from the launch site at 11:46 am and 11:48am respectfully. In reality the payload was reduced to vapors with only some pieces surviving to sea impact in the same close vicinity to the second and third stages impact. Meaning the second stage and third stages impacted fairly close to one another as reported by U. S DoD sources.
It was previously indicated that both the second and third stages both landed fairly close to one another 1,270 (2,300) - 1,300 (2,330) kilometers from Japan or about 3,200km and (3,230km) from the launch pad. The first impact point of 2,300 km is where the shrouds from the payload and third stage impacted while the second point 2,330 km is where the second and third stage and payload came down close to one another. The planned impact point for the third stage and payload shrouds was 2,150 by 2,950 km. If the flight had gone normal the trajectory from the pad to the second stage impact point would have gone as far as 3,150 - 3,950 km from the pad or within the impact zone specified. This indicates that the separation of the third stage and its firing did not work properly. So the same earlier 1,270 - 1,300 km from Japan suggested impact point is incomplete data from a Japanese Self Defense Forces ship based source some 1,030 kilometers from Japan . This was clarified by Japan 's Self Defense Forces. Japans radar tracked the flight 18 minutes 2,100 km out from Japan with 7 minutes [ 11:37 am ] to first stage impact in the Sea of Japan after its 112-120-125 second burn but its radar systems range limit was 2,100 kilometers from Japan .
The digital globe image that caught the TD-2 in flight at about 35,000 feet with jet streaming is quite normal. The bright flare is light reflection back into the satellite camera called sentilization glare and its mirror multiple imaging such as seeing one light through a window reflected in a line of repeated images. However that picture blown up properly allows one to see the top of the first stage, second stage, third stage and payload shroud exactly as viewed in the DPRK released video of its April 5, 2009 launch.
Imagery Reveals the Suspected Expected Thirds Stage Design Details
Additional data gleamed from the Digital Globe imagery of March 26, 2009 does indeed reveal the top of the second stage and the image of the 27th revealed the top of the payload shroud below the top of the gantry umbilical tower last service level surrounding it. The Digital Globe image of March 29th of the whole vehicle on the pad revealed the third stage was at that time exposed with a tapered truncated cone adapter at its base and above it leading to the bulbous like payload shroud. Subsequent imagery review of the released video of the launch of the Taep'o-dong-2 by the DPRK revealed that a shroud was placed around the third stage to make the airframe smooth causing the bulbous shroud to appear as if it had disappeared. The third stage actually turned out to be longer than expected.
The Taep’o-dong-2B Design Approach was Chosen by North Korea
Back in 2004/2005 I suggested in written and illustrated design studies done initially for FAS and continued at Globalsecurity.org that the North Korean’s could improve the Taep’o-dong-2 initial design performance by replacing the initially planned altitude version of the No-dong-A second stage with the altitude version of the No-dong-B as its second stage and that is exactly what they did as the redesign of the vehicle that was commenced in the year 2001.
Overall the booster has undergone dramatic design revision from its original concept mock-up first seen in 1994 by US imagery and subsequent derived designs of 1997-98 reflecting an Iranian collaborative design effort. The first and second stage inter-stage areas have been totally redesigned. First stage exhibited four main thrust chambers but the steering system is not as clearly defined (vanes in the gas jet which circumstantially appears to be the case) for steering control.
Defining the Propellants
The gas jets fire from the four main thrust chambers has a yellow orange color and a hydro-carbon black gray smoke like trail indicating a hydro-carbon based fuel of gasoline and kerosene like that of the Scud and No-dong-A series. That is combined with red fuming nitric acid oxidizer and nitrogen tetroxide with inhibitors to cut the corrosiveness of this highly toxic corrosive hypergolic propellant combination. There was no clear evidence of a soft gas after the pump turbine actuation exhaust being dumped overboard but this rarely displays itself on No-dong-A launches.
The No-dong-B, IRBM launch vehicle that North Korea and Iran are documented to have flight tested and deployed appears to be the basis of the second stage. It could be that the No-dong-B propulsion system was redesigned to accommodate these propellant combinations and not UDMH, IRFNA but that remains uncertain. Choosing UDMH and IRFNA over the IRFNA and hydro-carbon combination would provide a better over all performance for the system. The second stage apparently utilized UDMH with inhibited red fuming nitric acid while the first stage utilizes hydro-carbon based fuel of gasoline and kerosene with inhibited red fuming nitric acid.
Design Analysis Issues
In analyzing the second stage of the Unha-2 booster to scale the entire booster it was found that it was impossible to match it to the No-dong-A tank age diameter or length. To assume a reduced length or modified tank age diameter size of an altitude modified version of the No-dong-A seems impractical in all cases because of its original concept seen in 1994 and subsequently and because of its impact on the boosters overall performance. The original design left a lot to be desired performance wise as the Globalsecurity.org design studies revealed.
When applying the No-dong-B as an altitude version of the stage it did match fairly closely from the known design details .
Using strictly the second stage design diameter and length of tank age was not reliable enough to settle the issues of the true scale of the Unha-2 booster so I turned to the estimated the gantry umbilical towers railing height of about 42”-52”/54” inches tall with some clear unknown tarpons support architectural standards involved. It also indicated that the suggested 30 meter height of the gantry umbilical tower is not correct to what ever was being analyzed height wise introducing many undefined variables. Its height appears to be as much as 32.75 meters to the crane base from the ground.
This has still left this analyst unhappy with the large variables results except to say the original design underwent dramatic design changes during the 2001 through 2005 five year plan. Ultimately the rear gantry umbilical towers 42 inch tall railing will probably prove to be the real scaling answer along with the Solid motor third stage dimensions identified that will finally define the close design dimensions.
Unha-2, Taep'o-dong-2B Final design
Booster Size Brought into Perspective
The result is a booster varying between 27-30-32-33 meters in height with a first stage larger than the suggested 2.2-2.25 meter diameter now suggested to be 2.4-2.44 meter diameter with a revealing 2.4- 2.5-2.6 meter diameter variable possibility to accommodate the four engine cluster of No-dong-A engines. This gives a first stage lengthy of on the order of 14.5-15-16-16.6 meters.
The second stage has a length of on the order of 8-9.6 meters and its known No-dong-B, 1.5 meter diameter obscured by external tunneling that uses a set of translation, staging, attitude control thrusters near the flared skirt base with it single altitude vacuum thrust larger diameter exit nozzle.
The third stage appears to be a modernized variant of the Chinese [PRC] Long March-1 last stage solid motor with an active attitude control system. The stage has a maximum outside diameter of 1.35-1.37 meters and utilizes a shroud outside the solid motor of 0.7665 meters diameter below the payload shroud and above the stage reaction control package at it base. Its total length is about 3.948 meters or just over 6 meters with the payload shroud above it. The payload shroud with its Chinese design details characteristics is about 1.35 meters in diameter except at the separation seam which is about 1.37 meters in diameter.
Weapons Systems Application
The booster design can accommodate a 1.35 meter base diameter conical re-entry vehicle of 1,158 kilogram or a 650 kilogram tri-conic warhead design with a smaller base diameter. Certainly the range performance analysis of the booster subsequent to its flight test on April 5, 2009 must leave all previous analysis in the waste bind suggesting a considerable upgrade in the design than previously considered. The implied minimum range performance of well in excess of 6,700 kilometers to as much as 10,000 kilometers has apparently surprised the intelligence community still trying to analyze what they acquired from the April 5, 2009 launch.
Guidance System Performed
The guidance system performed from liftoff much better than that seen with the 1998 Taep'o-dong first satellite launch attempt. Taep'o-dong-1 flew near vertically before angling over and moving down rang but this Taep'o-dong-2 almost immediately curved over heading down range as a satellite launch should carry out in a very smooth flight pattern. It was even possible to see it correct its direction of flight as it moved down range soon after launch.
To say the least the original design for the Unha-2 booster underwent dramatic design changes during the 2001 through 2005 five year plan greatly improving its performance design.
Unha-2 Second Flight Test Kwangmyeongseong-2 (Lodestar) Satellite Payload
© By Charles P. Vick (All Rights Reserved)
Senior Technical Analyst, Globalsecurity.org
4-29-09 — 07-04-09
Several years ago prior to when North Korea had opened an exhibit of a mock up of its original satellite at its science museum in it capital North Korea announced it would launch a Communication, weather and ERTS satellites in a few years. Only the Kwangmyeongseong-1 and its model of the Taep'o-dong-1 with its launch gantry umbilical tower were shown with no images of the other spacecraft models displayed. It also displayed a communications satellite mock up that was said to be several years from launching. This satellite, presumably named Kwangmyeongseong-2 (Bright Lodestar-2), was known to be the payload of the first and second attempted Taep'o-dong-2 (Unha-2, or Galaxy-2) launch. It had also been suggested that a weather satellite could have been the payload for that launch.
The launch of the Kwangmyeongseong-2 (bright Lodestar) Satellite, planned for April 2009, was expected to be a technology demonstration flight test. The satellite payload mass was expected to be in the 100-170-250-550 kilogram range (verses a 1,158-650 kilogram dummy warhead). Observers suggested it could turn out to be an Iranian, Chinese or Iranian/DPRK satellite, based on a payload shroud fairing design previously displayed in Iran . The launch was carried out during the day April 5, 2009 , between 2-7 AM GMT ( 1 AM - 4 PM KST or 9 PM - 2 AM EST ). The projected inclination of about 40.6 degrees or a 90.5 degree easterly heading was not the usual type for either a weather satellite or a COMSAT, but more like a test experimental scientific satellite. Observers noted at the time that North Korea had little choice but to use the one inclination available to it, so as to only cross one country ( Japan ) for an extremely short period of time.
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