It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Some features of ATS will be disabled while you continue to use an ad-blocker.
According to Deputy Prime Minister Yuri Borisov, quoted by TASS, the emergency escape system was activated at T+123 seconds in flight. As a result, the escape began after the separation of the emergency rockets (at T+114.6 seconds) and the first stage at T+117.80 seconds at an altitude of around 50 kilometers.
A few hours after the accident, RIA Novosti quoted industry sources as saying that telemetry analysis had pointed toward a possible pyrotechnics separation problem between the first and second stage. According to industry sources quoted on the Novosti Kosmonavtiki web forum, the pressurization valve on one of the strap-on boosters of the first stage failed to open as scheduled to push it away from the second stage during separation and it led to the collision of the empty booster with the firing second stage and damaging or pushing it off course. According to Interfax, the impact of the first-stage booster caused the rupture of a (propellant tank) on the second stage and the loss of attitude control (of the entire vehicle). (Under normal circumstances, the nozzle of the oxidizer tank pointed 45 degrees relative to the main axis of the strap-on booster, generates reverse trust upon opening of the valve.)
Images available from the BSVK video system confirmed abnormal behavior of the D strap-on booster of the first stage with the failed oxidizer valve.
The accident took place during a phase of the flight, known as No. 1A, extending from the separation of the main escape rocket to the separation of the payload fairing protecting the spacecraft from aerodynamic loads. During that period, the propulsive role in ejecting the spacecraft from a failing rocket shifts to four solid motors, RDGs, attached to the payload fairing. One pair of these motors is activated on the emergency command and the other two engines fire 0.32 seconds later.
The failure command is issued on the basis of the data from angular velocity sensors on the second and third stages of the rocket. When those sensors detect a deviation of the vehicle exceeding seven degrees on the second stage or 10 degrees on the third stage, they generate an "avariya" (accident) command, which triggers the emergency escape sequence. However, after the separation of the four boosters of the first stage, the emergency escape scenario has a six-second pause to allow the firing core booster of the second stage to stabilize its flight after the somewhat violent separation process.
As a result, on Soyuz MS-10, following the "avariya" signal, which was displayed on the crew's console in the cockpit, four RDG motors were activated and pulled the payload section, OGB, including the Descent Module with the crew and the Habitation Module, away from the rocket, at T+122 seconds. Next, at T+160 seconds, the Descent Module was separated from the OGB stack and the capsule with the crew then entered free fall, heading for reentry into the Earth's atmosphere. Around that time, the crew (on the advice from mission control) activated the ballistic descent mode. The successful touchdown of the capsule took place around half an hour after liftoff, NASA officials said. However, mission control in Houston had some period of communications blackout, which obviously racked some nerves on the ground.
originally posted by: Flyingclaydisk
a reply to: wildespace
Candidly, I didn't quite understand that either, but the fella who said this is a pretty credible space / rocket blogger.
Let me see if I can find the video again. I think he's Irish or Scottish or something. If I find it again I'll post it.
the Descent Module was separated from the OGB stack and the capsule with the crew then entered free fall, heading for reentry into the Earth's atmosphere. Around that time, the crew (on the advice from mission control) activated the ballistic descent mode.