Facts and hypotheses about the accident "Union MS-10"
Haste is evil. Rereading publication 3r3107. with the chronicle of the accident "Union MS-10", which was conducted without delay, and you find mistakes. But now, when the dust has settled, the hands do not tremble from the situation “the ship went to an emergency landing, and the crew lost contact,” and in open sources there appeared better materials, it’s time to understand what happened.
Track of the Soyuz MS-10 flight on a long exposure, photo by NASA /Bill Ingals
There were two start-up broadcasts, from NASA-TV and Roskosmos. More complete is the first, there are heard the crew talks with the ground after the accident.
Both broadcasts successfully complement each other - Roskosmos shows the view from the ground, and NASA-TV data from the camera inside the ship.
Having superimposed the time from the video on the timeline of the flight, we obtain the following sequence of events.
114 seconds: according to the flight program, the emergency rescue boom is separated.
117 second: the process of separation of the first stage begins, which consists of several stages. He is clearly abnormal. NASA photographer Bill Ingals takes a photo in which the immediate cause of the accident is clearly visible - one of the four first-stage blocks was somehow separated differently and did not have time to go the same distance as the rest of the staff. The white dot is lower - the SAC boom dropped, that's normal.
Photo by NASA /Bill Ingals
In the area of 119 seconds from the ground, we see a cloud caused by damage and depressurization of a tank, most likely the second stage. The view inside the ship shows a noticeable decrease in overload (normal for separating the first stage) and then a serious jerk to the left (obviously abnormal). In the next photo of Bill Ingals, we still see the fourth block that has departed and some fragments that do not happen in normal separation.
Alas, instead of real telemetry, Roskosmos broadcasts animation, how a normal flight should go, so the picture transmitted to them on NASA-TV ceases to correspond to reality. Most likely, communication with the ship disappears, because in the broadcast of Roskosmos, the announcer continues to read a report based on a piece of paper as during normal flight (in case of problems, the announcer used to switch to the countdown of seconds without comment, and he reported on the apparent accident on the air and stopped reporting).
In the area of 160 seconds, the audio of the Soyuz spacecraft's shortwave transmitter appears, transmitting the “AN” - “carrier crash” to the Morse code and the report by cosmonaut Alexei Ovchinin: “Two minutes and 45 seconds. Carrier accident. In the broadcast of Roskosmos, the audio channel is promptly disconnected, then the speaker stops talking, and after a few minutes everything is turned off. The broadcast NASA-TV heard the dramatic negotiations of the crew in the ship, going to an emergency landing. As a result, the ship landed, the astronauts, alive and well, were evacuated.
So, from the photo and video it is obvious that the cause of the accident was an abnormal separation of the steps. Can you try to say more precisely?
How is the separation of the side blocks (first stage) from the central (second stage)? This process is described in the most detailed and clear way on the site 3—3—3106. CIC USSR 3r3107. . In a brief retelling, it consists of the following steps.
Start with Kuru, video ESA
First, the engines of the side blocks are transferred to the low thrust mode, and the steering engines are turned off. Further, the lower links of the side blocks are broken, and since the direction of thrust of the engines of the side blocks is specifically made not coinciding with their axis, the lower parts of the side blocks begin to diverge to the sides.
Screenshot simulator Orbiter
Then their engines are turned off, and since the second stage engine is running, the side blocks are lagging behind, are shifted back and come out of the upper mounts.
Top mount, photo KIK USSR
The red circle in the center is the valve cap of the oxidizer tank, a photo of the KIK USSR
When the side blocks depart a sufficient distance, the valve of the oxidizer tank opens, the jet stream from which twists the blocks. Well, in the last turn, the valve of the fuel tank opens, the jet of gas from the pressurization of which additionally twists and leads the stage. It is important to note that the upper part of the blocks passes a rather complicated path - first along the step down, then to the side.
KIK scheme of the USSR
What could have happened to the emergency unit? There are a lot of options - the engine finished working earlier, the engine worked longer than expected, the lower mounts did not work and the lower mounts did not disperse, the oxidizer valve did not open. Do we have any additional information? Yes - we saw on the video how the astronauts were jerked to the left. But which way is it "left" on a rocket?
Here is a photo of the launch of the Union MS-10 from the same Bill Ingals.
If you look closely, you can see three protrusions that allow you to determine the position of the ship under the fairing.
These protrusions are VSK fairings (“Special cosmonaut Vizir” - a device for manual docking and orientation, in fact, a periscope) and two infrared vertical sensors.
Photos of NASA
The rocket did not turn over in flight, so these fairings were at the top and at the time of the accident. VSK is installed under the feet of the astronauts (hence, by the way, an interesting conclusion - the Soyuz, like, for example, the shuttle, goes into orbit upside down). And the jerk to the left, which is visible in the broadcast, was in the direction of the emergency unit. This makes it less likely that versions of extra out-of-order thrust from him, and more likely, on the contrary, he somehow pulled the missile along with him. So, the leaked version of the oxidizer tank valve in the media looks quite plausible - if the unit hit the second stage, the power cone at its upper part ripped its wall and dragged it along, the astronauts would just pull in its direction.
But it is worth noting that there is no trust of the “favorite sources in the industry”, and the causes of similar accidents were very diverse. At the forum of the journal "News of Astronautics" led list:
1. 06/20/1967 - Voskhod - Plesetsk - Emergency shutdown of the propulsion system of the central unit A of the second stage PH at ??? sec due to the opening of the fuel tank of the central unit A of the second stage due to collision of the side unit D of the first stage with the central unit A of the second stage at 122 sec at separation due to non-disconnection of the telemetric connector.
2. 03/28/1981 - Soyuz-U - Baikonur - Emergency shutdown of the propulsion systems of the central unit A of the second stage and side blocks B, C, D and D of the first stage PH at ??? s due to the collision of the side unit B of the first stage and the central unit A of the second stage 117.7 sec due to non-detachment of side block B as a result of disconnection of the plug-in plug Ш144 of the side block B at the estimated time in the process of regular separation of the side and central blocks due to the failure of the DP-2 relay type DP-12 in the 11L1126 device or rubbing of individual veins in the B11U cable in flight due to accidental damage to the metal hose of the cable.
3. 03/26/1986 - Soyuz-U - Baikonur - Unusual separation of the side block G of the first step from the central block A of the second step of the PH due to the non-retraction of the upper part of the side block G due to the failure of the command to receive the keypad BU302-0M opening of the cover B4300-845M the jet nozzle of the oxidizer tank due to the non-exit of the stem of the B4411-0A contact sensor as a result of its jamming in the housing due to the deformation of the stem when assembling the “package” at the cosmodrome caused by the joining of the side block G with a random deviation from the requirements of technical documentation and a thrust bearing
the mutual position of the blocks when spherical bearing connections and input.
Two more questions remain unclear - why did the accident signal appear at 160 seconds, and did the emergency rescue system work?
About the work of CAC
According to the cyclogram, the emergency rescue system bar is reset to 114 seconds. But the SAS of the Soyuz ship consists of two parts - a rod and engines on the head fairing.
[i] SAS scheme of the Soyuz spacecraft, illustration of a corporation of tactical missile weapons 3r323838.
From -15 minutes to 114 seconds in the event of an accident, the engines on the rod and head fairing are triggered (from 4:4? the work of the RDG is clearly visible at 4:52).
From 114 seconds to 157 seconds in the event of an accident, the ship is diverted on the RDG engines in the head fairing.
And in the event of an accident after 157 seconds, when the head fairing is reset, it is separated from the third stage by regular pyrobolts, as if it went normally into orbit.
Accordingly, once the accident occurred at 119 seconds, the head fairing has not yet been reset. And according to the information from the Cosmonautics News Forum, when the first stage is separated, the automatic control system of the SAS is turned off for 6 seconds so that the control system of the launch vehicle can cope with disturbances. When SAS switched on again at 123 seconds, it estimated the position of the rocket as abnormal and tore the ship from it. The connection was lost, because the power supply and equipment remained in the instrument-aggregate compartment, which the CAC does not save. And already in the region of 160 seconds, when the descent vehicle was dropped from under the head fairing, its autonomous communication system was activated, which is used during landing during landing. This, by the way, explains the accident information that appeared in the media at 123 seconds.
According to the latest news, the emergency commission will work until October 25. Also, information appeared in the media that the video control system was on the rocket, a picture with which we might even someday be shown. A serious accident with the destruction of the rocket, after which the crew, through the efforts of automation, is alive and well, leaving an inappropriate sense of victory, and it will be very interesting to watch these shots.
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