2015 Jan 29
Thursday, Day 29
Proton Launch Failure 2012 Aug 6
Russia left two communications satellites, the Indonesian Telkom 3 and its own Express-MD2, stranded in the wrong orbit after a perfect lift off for a Proton-M/Briz-M rocket.
Launch at 19:31 UTC was into a clear sky above Baikonur. The launch webcast followed the rocket right through the first stage of flight, through ignition of the second stage and ejection of the payload fairing and well into the second stage.
The three Proton rocket stages performed flawlessly. The spent Stage 3 headed for a re-entry over the eastern Pacific Ocean south-east of Japan and the Briz-M stage then took over for a pre-planned, short, firing. It injected itself and the attached stack of satellites into a perfect 172 x 173 kilometre parking orbit at 51°.55 inclination.
A second firing of the Briz-M main engine at 20:38:25 UTC, for 17 minutes and 55 seconds, resulted in an orbit measuring approximately 266 x 5014 kilometres at 49°.9 inclination. At 22:59:54 UTC the Briz-M fired again but shut down after only seven seconds rather than the pre-programmed eighteen minutes. It resulted in little change to the orbit.
The Briz-M computer continued to function. The satellites were released into independent orbit either by an emergency procedure, or automatically as the result of it sensing the shutdown and assuming the launch mission had ended.
The pre-planned release times were August 7 at 04:44 UTC for Telcom 3 and thirty minutes later for Express-MD2. However, there is evidence that the releases occurred somewhat earlier.
At 04:08 UTC, Kevin Fetter, an well-known amateur satellite observer based in Canada was unaware of the failure. Using a set of orbital elements released by SpaceTrack after the 20:38 UTC engine firing, he set out to observe the Briz-M stack. Instead, he was treated to the sight of a 'train' of four objects crossing the sky. They were the two satellites and the Briz-M, and the fourth item was either the Briz-M's Auxiliary Propellant tank (APT) that was due to be jettisoned after the engine firing or a piece of debris.
Kevin posted the video to YouTube:
The Mission Plan
A map issued by the Khrunichev company prior to the launch depicts mission events. The four planned firings of the Briz-M are marked as is where the failure occurred, plus some other major launch events. The second and third firings, lasting nearly 20 minutes each occupy long segments of the orbit.
This is the second Briz-M failure to deliver in less than twelve months. After launch on August 17 last year, Russia's Express-AM4 comsat was lost. In that case, the Briz-M completed everything it was instructed to do but there was an error in its computer programming that resulted in the wrong orbit being achieved.
At present the cause of the failure is not known but the satellites are probably a lost cause. It is unlikely that either has enough propellant to climb anywhere near its intended orbit. Given that the last Briz-M failure was down to a computer programming fault, human error could be a factor in this case too.
The next planned launch of a Briz-M stage is scheduled for later in August, on a similar mission to this one, carrying the Intelsat 23 satellite to geosynchronous drift orbit. This failure puts it in doubt.
An Interdepartmental Commission, based round Roscosmos and Khrunichev - the Proton operator, began work August 7 to determine the cause of the problem. Telemetry had revealed that the Briz-M engine shut down seven seconds into its third firing because the control system detected a problem wih the thrust.
An article published by the Russian newspaper "Kommersant" August 8 said that the main culprits being looked at were low-quality fuel and a failure of the turbo-pump, taking human error off the table. It also said that the possibility of a clogged fuel line had apparently been eliminated. On August 9, Kommersant, in a contradiction it's previous day item, said that the cause had been narrowed down to a damaged feed line or fuel contamination, either of which could have restricted flow to the engine.
August 16 - ITAR-TASS reported that the failure was caused by a blocked pressurisation line in the Auxiliary Propellant Tank that resulted from a manufacturing fault. It also reported Vladimir Popovkin as saying there was no danger of an explosion of the Briz-M because internal pressures in the tanks had been reduced to zero.
Normally, The Briz-M auxiliary propellant tank (APT) is pushed backwards from the Briz-M, which causes it to drop to a slightly lower orbit from where it starts to overtake and move ahead of the Briz-M.
In this photograph, the 4m diameter Auxiliary Propellant Tank surrounds the Briz-M itself in the configuration. APT's white cladding and the fact that it is one and a half times the diameter of the Briz-M core make it a relatively bright object when observed from the ground. Compared with the Briz-M, it is in the region of 1-2 stellar magnitudes brighter.
Telkom 3 and Express-MD2 were planned to be released about thirty minutes apart and the data from mission control does not show any planned thruster operation by the Briz-M in between. Separation usually results in the satellites moving to a slightly higher orbit so the Briz-M can operate its thrusters to move safely downwards and away. If this is what happened here, then the satellites would start to fall behind the Briz-M and take up the reverse of the order in which they were released. The order would be: APT, Briz-M, Express-MD2 and then Telkom 3.
If the APT did not separate from the Briz-M then the order would be: Briz-M, Express-MD2 and then Telkom 3. The fourth item would be sitting in the Train at a point determined by when in the sequence it separated.
Because it was not immediately obvious what the individual objects in the Train were, SpaceTrack named them temporarily "OBJECT A" through to "OBJECT D". On August 11, it named them formally and switched round the way it was allocating element sets to the four objects. The reason for the switching was to get future element sets correctly lined up with the International Designations - '2012-044A' and '....B' for the satellites, '...C' for the Briz-M and '...D' for the fourth object:
For launches in recent years, SpaceTrack has been identifying the APT as a distinct item. It usually gets the name "BREEZE-M DEB (TANK)". The fact that object 2012-044C/38747 was initially identified only as debris indicated that SpaceTrack was uncertain that it is an APT. The fact that it was not leading the Train when first observed supports the idea of it not being the APT. August 14, SpaceTrack renamed it as "BREEZE-M DEB (TANK)" but amateur visual observation of all the objects continued to show it as the least bright even though the APT is physically the largest of the four items. August 22, SpaceTrack had a re-think and decided it is not the APT after all. NOTE - SpaceTrack's naming convention calling it "BREEZE-M" is incorrect.
2011's dual launch of SES 3 & KazSat 2 resulted in an extra object being catalogued when compared with previous Briz-M missions. SpaceTrack called it "BREEZE-M DEB (ADAPTOR)". It was a connector to allow the satelites to be stacked on top of each other.
Kazakhsat 2 from the earlier launch and the current Express-MD2 share a common design, being built around an element of the Briz-M structure. As a result, an Adaptor was needed on this mission and it is almost certainly SpaceTrack's 'Debris' rather than it being the APT.
The 2m diameter adaptor can be seen in this image of Telkom 3 in the assembly building.
At a Glance
This plot shows all Twoline Elements Sets issued for the four objects. The colour coding represents the ID contained within the element set so the switching around of IDs is obvious. The lines join the sets in colours to match SpaceTrack's REVISED allocations of ID.
Briz-M's low decay rate is due to the amount of propellant still inside - more than 50 percent of the original amount. It leads to a large mass/cross-section ratio.
August 8 - The orbital period of the Briz-M increased very slightly as a result of thrust being applied (see note for August 16).
August 10 - As of early in the day, Telkom 3 was decaying at a new, faster, rate. Later, there was a minor increase in Express-MD2's decay rate, a sign maybe of an attitude change increasing the mass/cross-section ratio, or even the start of tumbling.
August 13 - Reshetnev, the company that built Telkom 3 issued a press release saying that the satellite was communicating and was under control. It also said that the solar panels had been opened, explaining the increase in the decay rate on August 10 when they added to the atmospheric drag being experienced at perigee.
August 16 - ITAR-TASS reported Vladimir Popovkin as saying there was no danger of an explosion of the Briz-M because internal pressures in the propellant tanks had been reduced to zero. It probably explains the small orbit change of the Briz-M late August 7 or early August 8 through thrust caused by release of pressurising gas.
October 16 - Vladimir Popovkin's assurances seemed to to lose weight as fuel and oxidiser within the Briz-M tanks came into contact, triggering an explosion.
Which Piece is Which?
The plot allows the individual items to be identified and it flags up many of the wrong allocations that occurred early on.
Using the plot as a guide, a set of early Twoline Orbital Elements can be selected that represent the initial orbits of the four objects. From them, it is possible to look again at Kevin Fetter's observation and identify what it shows. Of the two pictures below, the upper one is part of a frame from the video, labelled using SpaceTrack's Names.
The names have been derived from the lower image that uses a satellite tracking computer programme called Heavensat to model the orbits at the time video was created. Four stars are labelled A, B, C & D to help match up the two images. The centre of the frame is near RA 21h 46m, Dec 28° 30' in the constellation Pegasus, and the field is about 4° across.
Heavensat produces a good match to the video, so we can identify for sure the order of the objects and their relative brightnesses. The Debris is the least bright of the four, as might be expected.
Because of the Debris item's position in the Train, it is likely to be the inter-satellite Adaptor. This then tells us that the APT is almost certainly still attached to the Briz-M rocket stage.
A visual observation from the zarya.info observing location in the UK on the evening of August 7 produced the following approximate visual magnitudes, Telkom 3 (prior to solar panel opening): +5, Express-MD2: +7, Briz-M: +5·5, Debris: +7·5.
In an August 17 posting to Seesat-L, an observer in Colorado estimated them as +3, +4, +3, and +5.5 respectively. The additional 2-3 magnitudes brightness compared with the UK sighting is due to the angle between the Sun, the satellites and the observer producing a more 'full on' illumination. The relative brightnesses are in line with the earlier UK observation. The observation confirms that SpaceTrack's "Tank" is nothing like as bright as it should be, strengthening the idea that the APT is still attached to the Briz-M and that 044D/38747 is something much smaller.
Page Date: 2012 Aug 13
Updated: 2012 Aug 15
Updated: 2012 Aug 16
Updated: 2012 Aug 17
Updated: 2012 Aug 20
Updated: 2012 Oct 16
Updated: 2012 Oct 21
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