During its 7th orbital launch, the Dnepr launcher was scheduled to carry the BelKA remote-sensing spacecraft for the government of Belarus, as a primary payload, along with a number of smaller satellites: UniSat-4, Baumanets, PiCPoT and five P-Pod containers with 14 CubeSat satellites. According to some reports, the R-36M UTTKh missile converted into the launch vehicle for this mission was originally deployed in 1980.

Payloads of the Dnepr's 7th orbital mission:

*according to Roskosmos

Pre-launch processing

The mission was delayed from February, March and June 28, 2006. The BelKA was delivered to Baikonur on May 11, 2006. The Baumanets satellite arrived to the launch site on June 5, 2006. At the time, the launch was planned for June 28, 2006, however in the first half of June a problem was discovered in the onboard computer of the Dnepr launch vehicle. Despite attempts to replace defective elements, problems persisted. As a result, officials made a decision to replace the launch vehicle for the mission. The defective booster was removed from the silo on June 16, 2006.

Dnepr fails during launch with multiple payloads

Published: 2006 July 26

In its second mission of 2006, a converted Russian ICBM failed early in flight, crashing downrange from Baikonur.

The Dnepr launcher converted from the R-36M UTTKh missile lifted off on July 26, 2006, at 23:43 Moscow Summer Time from Site 109 in Baikonur, heading south to a near-polar orbit with the inclination 97.43 degrees toward the Equator.

The separation of the BelKA spacecraft from the upper stage of the launch vehicle was scheduled 901.5 seconds after launch.

According to deputy head of Roskosmos Yuri Nosenko, quoted by the Interfax news agency, the failure took place during the firing of the first stage of the launch vehicle 86 seconds in flight, or some ten seconds before a scheduled shutdown of its engines. In the nominal flight, the first stage of the Dnepr rocket would fire for around 1 minute 38 seconds. Nosenko said that the launch vehicle crashed 25 kilometers south of its launch silo, however on July 27, Kazakhstan's Ministry of Emergencies said that the failure of the Dnepr rocket took place 73 seconds in flight and it crashed 189.6 kilometers downrange from the launch site, or six kilometers north-east of Tagai winter pasture, on the border with Uzbekistan.

Officials in Baikonur said that initial attempts, (using the Antonov-2 biplane aircraft), to locate the crash site were were unsuccessful.

According to a witness of the launch, the flame of the first stage has disappeared some 69 seconds after the launch, followed by three red flashes with ever decreasing brightness until the 73rd second after the launch.

Ground control sent commands to shutdown the rocket's engines at 73.89 seconds, when the vehicle exceeded the allowable yaw angle.

The telemetry was apparently continued flowing as long as five minutes after the launch. Preliminary data pointed to the failure of the 15L423 hydraulic gimbaling mechanism on one of the four main engines of the first stage.

Head of Belarus National Academy of Sciences Mikhail Myasnikovich, who was present at the launch along with President of Belarus Aleksander Lukashenko, was quoted by Interfax as sayings that BelKA was properly insured.

The impact of the crash

On July 28, 2006, Roskosmos and Russian Ministry of Defense announced the formation of an interagency investigative commission led by Director General of TsNIIMash research institute Nikolai Anfimov. The commission also included representatives from GKB Yuzhnoe, MKK Kosmotras and Russian Space Forces. The first official meeting of the commission was scheduled for August 4, 2006, in Dnepropetrovsk and its final report was expected on August 28, 2006.

On the same day, RIA Novosti reported that the search team from the Kazakhstan emergency ministry located the crash site 150 kilometers southwest of Baikonur. According to sources in Baikonur, posting on the Novosti Kosmonavtiki discussion board, the impact crater was discovered from the Russian military plane at 07:40 Moscow Time. The search team was then sent to the site with the task of recovering debris of the rocket, which could provide clues on the cause of the accident. The investigative team reached the crash site at 15:00 Moscow Time.

On the night of July 28, 2006, the "Kazakhstan" TV channel showed a crater, estimated to be 50 meters in diameter. (Later reports said the crater was 30 meters wide and three meters deep.) Apparently due to explosion and fire, which followed the impact, only few remnants of the vehicle were visible at the site, among them a two-meter pipeline.

According to a representative of Kosmotras, the launch vehicle hit the ground intact, without separation of the rocket's stages or payload section and all toxic propellant burned during the following fire. The elements of the vehicle were believed to be buried at the bottom of the impact crater.

The official statement from Roskosmos echoed this information, saying that based on the shape of the crater, the vehicle was falling almost vertically, head first. According to Roskosmos, environmental samples taken from the crash site by officials from NPO Mashinostroeniya showed that excessive concentrations of toxic substances do not exceed a one-kilometer radius. Russian officials also said that that any remaining propellant being an unstable chemical would dissipate quickly.

General area of the crash was reportedly populated by some 2,000 people with the town of Zhanakala, being closest to the impact site.

Kazakh reaction

Despite Russian assurances, on July 31, 2006, RIA Novosti reported that Kazakhstan's prime-minister Daniel Akhmetov ordered creation of a state commission assigned to evaluate the environmental damage from the Dnepr failure and calculate financial damage from the accident. The Kazakh team apparently detected traces of toxic propellant in the impact crater in the amount of 1,000 milligrams per one liter and responded with closing access to the town of Zhanakala and Kuandariya. Kazakhstan also evacuated a personnel from the Kerkeli border guard unit (Base No. 2019) based on the Kazakh-Uzbek border, according to RIA Novosti.

On August 1, 2006, quoting Article 5 of the Kazakh-Russian agreements from 1999 on the use of Baikonur, the representative of the Kazakh government Azamat Abdymomunov announced a ban on further launches of Dnepr rockets. Kazakh government also created its own investigative commission to deal with the accident. However, Roskosmos denied that all launch vehicles using the same propellants as Dnepr, including Proton, would be grounded. At the same time, Roskosmos confirmed that Russia would compensate the Kazakh government for any environmental damage caused by the accident.

According to Ivan Safronov, a well-informed reporter from Kommersant newspaper, during the first joint meeting of investigators from Russia, Ukraine and Kazakhstan, on August 4, 2006, Kazakh officials estimated that their bill to Russia for the crash would reach $1.6 million, however the exact sum would be presented during another meeting a month later. This amount apparently included the cost of travel to the impact site, environmental impact work and medical exams of the local population. However on August 8, Kazakh commercial TV channel said that Kzyl-Orda region presented the Baikonur Cosmodrome with a $296 million bill, which is almost three time of Russia's annual payment to the Kazakh government for the rent of the cosmodrome. This sum was then widely quoted in the Russian media, however Russian officials vehemently denied the accuracy of the number.

At the same time, the representative of the Kazakh foreign affairs ministry Ilyas Omarov said that in the wake of the Dnepr accident, Russia and Kazakhstan agreed on several changes in a treaty on Baikonur.

In addition, on August 3, 2006, Khabar news agency reported, that the local district attorney office of Karamakchinskiy District launched its own criminal probe, under Article 282 of Kazakhstan Criminal Code, entitled "The Environmental Contamination with Toxic Chemicals."

The investigation

From the beginning, investigators focused on the steering mechanism of the engine No. 4, which apparently stalled in flight. In addition, preliminary data showed that one of four engines on the first stage, (Engine G) did not shut down properly. An official statement from Roskosmos on July 29 said that anomalous deviations in the thrust vector was detected at the end of the first stage burn, causing the vehicle deviate from the nominal trajectory and when it exceeded allowable limits, the rocket's engines were shut down.

However the investigation into the failure had hardly started, as the newly appointed press-secretary of Roskosmos, Igor Panarin, essentially blamed Ukrainian-made components of the launch-vehicle for the accident. Panarin's statement was immediately challenged by a leak from one of the members of the investigative commission, most likely from Ukraine, who was quoted on Novosti Kosmonavtiki's discussion board. He said that the anomalous performance of one of the Russian-built engines caused vibrations, leading to deviations of the vehicle from the allowable course and yaw. The flight control system struggled to keep the vehicle on course, however ultimately, the rocket had to be liquidated. According to this source, the technical defect could originate during the manufacturing of the rocket back in 1981.

It was also reported on the same forum that for the first time during its 7th mission, the Dnepr was programmed to conduct a pitch maneuver between the 70th and 74th second in flight, designed to reduce the amount of propellant remaining onboard the first stage after its separation, and thus, reduce contamination of impact zones downrange from Baikonur.

Additional crash sites

In the meantime, on August 3, 2006, the Khabar news agency reported that Kazakh Ministry of Emergencies suggested that the Dnepr disintegrated into at least two large fragments while still at high altitude. This version of events was based on the account of a local hunting inspector, who reported two explosions in two different places on the ground on the night of the launch.

On August 7, the Interfax news agency quoted a member of the Kazakh investigation commission as saying that his nation's emergency ministry officials found a fragment of the payload fairing from the Dnepr rocket, some 25 kilometers south of Baikonur.

Most likely explanation for the find was violent oscillations of the vehicle, resulting in extreme aerodynamic loads, which caused the payload fairing to shear off. However according to another hypothesis, it was the disintegration of a defective payload fairing early in flight, which caused increased aerodynamic loads on the vehicle and the resulting loss of control.

During the afternoon of August 10, 2006, the helicopter of the Kazakh ministry of emergencies located a third crash site, some 40-50 kilometers downrange from Baikonur, or as far as 90 kilometers from the launch site. This latest site reportedly included remnants of the second and third stages of the Dnepr vehicle, as well as its battered payloads. The main impact site had a crater three meters in diameter and one meter in depth, however the entire debris field extended over one kilometer along the flight path.

Conclusions

On Aug. 9, 2006, RIA Novosti quoted a Russian official as saying that the cause of the failure has been established, however gave no additional details. Two days later, the same source quoted head of Roskosmos Anatoly Perminov as saying that "according to preliminary data, the abnormal performance of the combustion chamber No. 4" caused the accident. "Apparently, a considerable overheating of the fluid in the steering mechanism, controlling the combustion chamber has been taking place, Perminov said, "Number of things could lead to that and, currently, experts try to determine the cause."

Observers familiar with the design of the engine, explained that special oil is used in the gimbaling mechanism, which steers the engine, and that oil could loose its qualities over time.

The analysis of telemetry confirmed that soon after T+70 seconds in flight, a sharp increase in pressure was detected within the payload section of the rocket. Telemetry also showed that at T+70 seconds, flight control system sent a command to the engines to initiate a pitch maneuver. In response, the shaft of the gimbaling mechanism started moving. A following command from the control system was designed to slow down this movement, however it was ignored by the mechanism for about 0.2 seconds. When the mechanism finally stopped, the vehicle had already received oscillations, which only grew until gyroscopes of the flight control system, which normally keep the vehicle on track, stalled. The emergency command to shut down engines, known as AVD in Russian, had followed.

The telemetry also showed that the oscillations before the emergency shutdown of the engines, could not possibly cause the separation of the payload section.

On August 16, 2006, Kosmotras confirmed that the launch accident was caused by a brief malfunction of the hydraulic mechanism, which steered one of the combustion chambers of the launch vehicle. It led to the deviation of the rocket from its flight path and the emergency shutdown of its engines 73.9 seconds after a liftoff. According to Kosmotras, the cause of the malfunction has been found and the commission has been working on recommendations to fix the problem. At the time, the final report of the investigation commission was still expected on August 28, 2006.

PICTURE GALLERY

Stills from video showing an ill-fated launch of the Dnepr rocket on July 26, 2006. Credit: CalPoly

An estimated area, where Dnepr launcher crashed in July 2006. Click to enlarge. Copyright © 2006 Anatoly Zak