FAILURE: Soyuz MS-10 - October 11, 2018 - Baikonur (DISCUSSION)

[Norm38]

Launch of Soyuz MS-10

A different view than above, Check the video at 2:20

https://www.youtube.com/watch?v=CnQlj73NIm4?t=001

I'll start a discussion thread off with this video.

At timestamp 2:23 - 2:24, there is a dark disturbance in the exhaust plume.  The rocket continues to fly for a few more seconds before the deflagration occurs at 2:26.  I haven't seen this specifically discussed yet in the main (now updates) thread.

How many engines were firing at that point in the flight? Did an engine fail?  Something simply falling off the rocket wouldn't change the plume internally.  The launch abort tower jettison wouldn't cause that.  To me, it is engine related.  Thoughts?

[Norm38]

Another question.
I read in the update thread that the launch abort tower had already jettisoned before the failure.  Is that confirmed?
So the Soyuz capsule was completely passive?  All it could do was separate from whatever was left of the stack and hope for the best?  Is it setup to fire attitude control, use the landing braking thrusters to try and get separation, anything like that?

I'm impressed it came off unscathed.  But I guess a deflagration out of atmosphere can't create a pressurized shock wave, so can't do damage.
Is that part of the calculation as to when the abort tower can be jettisoned?

[whitelancer64]

Another question.
I read in the update thread that the launch abort tower had already jettisoned before the failure.  Is that confirmed?
So the Soyuz capsule was completely passive?  All it could do was separate from whatever was left of the stack and hope for the best?  Is it setup to fire attitude control, use the landing braking thrusters to try and get separation, anything like that?

I'm impressed it came off unscathed.  But I guess a deflagration out of atmosphere can't create a pressurized shock wave, so can't do damage.
Is that part of the calculation as to when the abort tower can be jettisoned?

No, after separation it can fire its own engines, exactly like it does to separate from the 3rd stage during a nominal launch.

The abort tower is jettisoned after 1st stage separation (booster separation) to save weight. Apollo did the same thing with its abort tower. Any abort after that but prior to entering orbit would have done the same thing the Soyuz did, which is separate from the 3rd stage and use thrusters to get away. Then jettison SM and prepare for reentry like normal.

[Ben the Space Brit]

FWIW, I'm pretty sure that the Russians will identify the cause pretty soon. Working through the fault tree to the root cause will take a bit longer but is just a matter of time. The real question is whether the Russians will be able to fix the root cause. 'The beatings will continue until morale improves' by way of highly-public naming-and-shaming followed by dismissal of individuals has notably failed to stem the problems to date.

[Phillip Clark]

To clarify about the Soyuz abort system.

The payload shroud now carries its own motors on the conical top.   So, the tower separates but the shroud is still surrounding the Soyuz, and the shroud's motors can fire to take the Soyuz away from the Blok I.

[abaddon]

Wow 34 minutes is much longer that I would expect. Would be good to query and get confirmation on that figure.

There's quite a bit of vertical velocity built up at this point that has to be zeroed out by gravity before the capsule begins its descent.  If the incident happened at 50km, what would the apogee be?  I have no idea but would imagine it to be quite a bit higher.

(Moved here from the Update thread)

[russianhalo117]

To clarify about the Soyuz abort system.

The payload shroud now carries its own motors on the conical top.   So, the tower separates but the shroud is still surrounding the Soyuz, and the shroud's motors can fire to take the Soyuz away from the Blok I.

Correct the SAS tower is only needed while the strap on boosters are attached. The Fairing oversees the core blok's operation until jettison. Blok-I is weak enough thrust that Soyuz can perform its own abort using its main engine and auxiliary engines/thrusters.

[abaddon]

At timestamp 2:23 - 2:24, there is a dark disturbance in the exhaust plume.  The rocket continues to fly for a few more seconds before the deflagration occurs at 2:26.  I haven't seen this specifically discussed yet in the main (now updates) thread.
How many engines were firing at that point in the flight? Did an engine fail?  Something simply falling off the rocket wouldn't change the plume internally.  The launch abort tower jettison wouldn't cause that.  To me, it is engine related.  Thoughts?

This is just shutdown of 1st stage (booster) engines and is normal.

[fthomassy]

Can someone confirm or clarify? The motors indicated were used for this abort ...

[matthewkantar]

This zoom in on Bill Ingalls' shot sure looks like three boosters separated earlier than the fourth. Would one booster staying put be enough to pull the core apart?

[Craftyatom]

Wow 34 minutes is much longer that I would expect. Would be good to query and get confirmation on that figure.

There's quite a bit of vertical velocity built up at this point that has to be zeroed out by gravity before the capsule begins its descent.  If the incident happened at 50km, what would the apogee be?  I have no idea but would imagine it to be quite a bit higher.

My napkin math still can't quite make these numbers fit.  The launch video included a simulation, which had a closest data point of T+130s, 1842 m/s speed, altitude 57km - this is higher and faster than the capsule would actually have been.  Assuming all of that velocity is upwards (it wasn't), we get a maximum apogee at T+318s, 0m/s speed, altitude 173km.  They would hit entry interface at T+440s, 1196m/s speed, 100km altitude.  According to this timeline, a nominal EDL takes at most 1500 seconds, and since this ballistic entry had to shed less speed, and did so with higher g-loading, I don't think it would take any longer than normal.  This gives us a maximum touchdown time of T+1940s, less than 31 minutes after the anomaly, even when erring on the long side.

Disclaimer: IANaRS, these calculations are dirty and uninformed, I've ignored air resistance in some stretches, and (importantly) I've not accounted for the curvature of the Earth.  Not to mention that floating under a parachute can take you many different places in many different amounts of time, depending on weather conditions and ground level.  However, I decided to post this anyways, in order to draw two conclusions, one minor and one important: First, while 34 minutes after the anomaly is theoretically within the realm of possibility, we should make sure that it has been reported correctly - their word is worth more than my napkin math, but it's still worth a look.  Second, and more importantly, I am almost certain that the MS-10 crew crossed the Karman line, and thus Nick Hague deserves wings [EDIT: I was overestimating the flight angle of the rocket - upon closer inspection, the apogee was likely 80km or less.  Thanks to the users who helped me with this below.] (though I imagine he probably "deserves" them regardless, all things considered).  An apogee below 100km at the speeds they were traveling would've required a flight angle of at most 34 degrees above the horizon, and I believe the rocket was much more vertical at the time.

[eeergo]

Can someone confirm or clarify? The motors indicated were used for this abort ...

Cross posting this from the Update thread, for reference.

The Soyuz Escape System in its deployed configuration (the stack would have been missing the slim tower above the fairing in this abort of course, since it was jettisoned a few seconds before the problem developed,as mentioned before). Source: [/size]https://danielmarin.naukas.com/2010/07/05/sas-rescate-de-una-soyuz/[/size] The abort in the time period spanning from escape tower jettison to fairing separation is performed with the lateral pusher motors on the fairing, NOT with Soyuz's own engine.


Also, in this video you can see the RDG motors firing in a "nominal" full abort (starts at 0:49, RDGs at 0:55)

[Stan-1967]

My understanding of the location of the abort motors active in todays event are circled in the attached picture.  The motors themselves are mounted inside the payload shroud.  Is this correct?

I also noted today that Soyuz launch animation on their broadcast are not tied to live telemetry, they are just animations of a nominal launch.  Just like what was seen on the Ariane V launch of SES-14

[eeergo]

My understanding of the location of the abort motors active in todays event are circled in the attached picture.  The motors themselves are mounted inside the payload shroud.  Is this correct?

I also noted today that Soyuz launch animation on their broadcast are not tied to live telemetry, they are just animations of a nominal launch.  Just like what was seen on the Ariane V launch of SES-14

Yes.

[russianhalo117]

My understanding of the location of the abort motors active in todays event are circled in the attached picture.  The motors themselves are mounted inside the payload shroud.  Is this correct?

I also noted today that Soyuz launch animation on their broadcast are not tied to live telemetry, they are just animations of a nominal launch.  Just like what was seen on the Ariane V launch of SES-14

yes those are the RDG traction motors that performed the escape from the rocket. There are 2 more motors (not visible) that fire later to complete the escape maneuver

[ChrisWilson68]

I'm very glad that the crew is safe!  That's the most important thing.

It's good that SpaceX and Boeing are close to being ready to launch crew to ISS.  They might be just in time to avoid a gap, or at least reduce the length of the gap, in ISS occupation.

I hope it doesn't turn out that this is sabotage related to the infamous drilled hole found in the other capsule.

[jcm]

Wow 34 minutes is much longer that I would expect. Would be good to query and get confirmation on that figure.

There's quite a bit of vertical velocity built up at this point that has to be zeroed out by gravity before the capsule begins its descent.  If the incident happened at 50km, what would the apogee be?  I have no idea but would imagine it to be quite a bit higher.

My napkin math still can't quite make these numbers fit.  The launch video included a simulation, which had a closest data point of T+130s, 1842 m/s speed, altitude 57km - this is higher and faster than the capsule would actually have been.  Assuming all of that velocity is upwards (it wasn't), we get a maximum apogee at T+318s, 0m/s speed, altitude 173km.  They would hit entry interface at T+440s, 1196m/s speed, 100km altitude.  According to this timeline, a nominal EDL takes at most 1500 seconds, and since this ballistic entry had to shed less speed, and did so with higher g-loading, I don't think it would take any longer than normal.  This gives us a maximum touchdown time of T+1940s, less than 31 minutes after the anomaly, even when erring on the long side.

Disclaimer: IANaRS, these calculations are dirty and uninformed, I've ignored air resistance in some stretches, and (importantly) I've not accounted for the curvature of the Earth.  Not to mention that floating under a parachute can take you many different places in many different amounts of time, depending on weather conditions and ground level.  However, I decided to post this anyways, in order to draw two conclusions, one minor and one important: First, while 34 minutes after the anomaly is theoretically within the realm of possibility, we should make sure that it has been reported correctly - their word is worth more than my napkin math, but it's still worth a look.  Second, and more importantly, I am almost certain that the MS-10 crew crossed the Karman line, and thus Nick Hague deserves wings (though I imagine he probably "deserves" them regardless, all things considered).  An apogee below 100km at the speeds they were traveling would've required a flight angle of at most 34 degrees above the horizon, and I believe the rocket was much more vertical at the time.

I am skeptical - it's easy for things to look more vertical than they are.
I think a flight angle of as low as 20 deg is perfectly plausible.

Does anyone have a proper Soyuz-MS launch profile with flight path angles versus time?

[mme]

Basically praying right now that the crew is going to be okay. Given the forces involved they may have survived the abort and descent but that does not mean they are out of danger. I do not like the lack of further information although NASA PAO is insisting they are "okay". Could be nothing just fog of war or bad translations I will hope that's the case.

As I understand the abort happened after LAS tower separation using engines in the shroud, and those are not as powerful as the ones in the tower because they only need to "outrun" a single booster with peak G-load of about 2.5G, while the tower has to be able to get away from the rocket doing up to 4G of acceleration. So in a way it was a more gentle abort than it could've been. But - yea, aborts are usually not designed to be comfortable nor even technically "safe", but merely survivable.

Yeah but the ballistic reentry from that altitude is no picnic. I think I heard that it would be over 7Gs.

[satwatcher]

I am skeptical - it's easy for things to look more vertical than they are.
I think a flight angle of as low as 20 deg is perfectly plausible.

Does anyone have a proper Soyuz-MS launch profile with flight path angles versus time?

From the animation shortly after stage 1 separation I get the following:
t=130.36s v=1842m/s h=57km d=69km
t=132.96s v=1860m/s h=59km d=74km

So rough angle is tan( 2km/5km) = 24 deg

[jcm]

I am skeptical - it's easy for things to look more vertical than they are.
I think a flight angle of as low as 20 deg is perfectly plausible.

Does anyone have a proper Soyuz-MS launch profile with flight path angles versus time?

From the animation shortly after stage 1 separation I get the following:
t=130.36s v=1842m/s h=57km d=69km
t=132.96s v=1860m/s h=59km d=74km

So rough angle is tan( 2km/5km) = 24 deg

Using this, assuming the 1.8 km/s is Earth-relative, azimuth 61 deg, ignoring drag I get
a -6177 x 80 km orbit.  So with drag it is probably a bit below 80 km apogee. Maybe around 70?
Anyone got a suitable drag model?