> Initially, it was suspected that the booster had been bumped when the gantry tower was put back in place following the abort and that this somehow managed to trigger the LES, but a more thorough investigation found a different cause. During the attempted launch, the booster switched from external to internal power as it normally would do, which then activated the abort sensing system. The Earth's rotation caused the rate gyros to register an approximately 8° tilt 27 minutes after the aborted liftoff, which the abort sensing system then interpreted as meaning that the booster had deviated from its flight path, and thus it activated the LES. The abort sensing system in the Soyuz was thus redesigned to prevent a recurrence of this unanticipated design flaw. On the other hand, the LES had also worked flawlessly and demonstrated its ability to safely pull cosmonauts from the booster should an emergency arise as it did years later in the Soyuz 7K-ST No.16L abort (26 September 1983).
The emergency condition of the Soyuz 7K-ST No.16L abort was not caused by rotation of the Earth, but by multiple failures that caused damage to the launch vehicle:
> The crew was sitting on the pad awaiting fueling of the Soyuz-U booster to complete prior to liftoff. Approximately 90 seconds before the intended launch, a bad valve caused nitrogen pressurisation gas to enter the RP-1 turbopump of the Blok B strap-on. The pump began spinning up, but with no propellant in it, the speed of rotation quickly exceeded its design limits which caused it to rupture and allow RP-1 to leak out and start a fire which quickly engulfed the base of the launch vehicle. Titov and Strekalov could not see what was happening outside, but they felt unusual vibrations and realized that something was amiss. The launch control team activated the escape system but the control cables had already burned through, and the Soyuz crew could not activate or control the escape system themselves. The backup radio command to fire the LES required 2 independent operators to receive separate commands to do so and each act within 5 seconds, which took several seconds to occur. Then explosive bolts fired to separate the descent module from the service module and the upper launch payload shroud from the lower, the escape system motor fired, dragging the orbital module and descent module, encased within the upper shroud, free of the booster with an acceleration of 14 to 17g (137 to 167 m/s²) for five seconds. According to Titov, "We could feel the booster swaying from side to side. Then there was a sudden vibration and a jerking sensation as the LES activated".
No worries! I wasn’t familiar with these launches offhand myself so your post piqued my curiosity leading me to look the history up myself. And you weren’t far off - if the original launch failure hadn’t occurred, it’s entirely likely that the second launch failure would have been lethal and possibly even more other launches besides that one. Safety and reliability is a moving target but is always worth investing in because it also helps drive costs down and reduces failure modes that may not even be detectable or predictable due to black swan events.
Soyuz 7K-OK No.1 was uncrewed and likely had the quirk with the gyros. One person near the launch on the ground was killed.
https://en.wikipedia.org/wiki/Soyuz_7K-OK_No.1
> Initially, it was suspected that the booster had been bumped when the gantry tower was put back in place following the abort and that this somehow managed to trigger the LES, but a more thorough investigation found a different cause. During the attempted launch, the booster switched from external to internal power as it normally would do, which then activated the abort sensing system. The Earth's rotation caused the rate gyros to register an approximately 8° tilt 27 minutes after the aborted liftoff, which the abort sensing system then interpreted as meaning that the booster had deviated from its flight path, and thus it activated the LES. The abort sensing system in the Soyuz was thus redesigned to prevent a recurrence of this unanticipated design flaw. On the other hand, the LES had also worked flawlessly and demonstrated its ability to safely pull cosmonauts from the booster should an emergency arise as it did years later in the Soyuz 7K-ST No.16L abort (26 September 1983).
The emergency condition of the Soyuz 7K-ST No.16L abort was not caused by rotation of the Earth, but by multiple failures that caused damage to the launch vehicle:
https://en.wikipedia.org/wiki/Soyuz_7K-ST_No.16L
> The crew was sitting on the pad awaiting fueling of the Soyuz-U booster to complete prior to liftoff. Approximately 90 seconds before the intended launch, a bad valve caused nitrogen pressurisation gas to enter the RP-1 turbopump of the Blok B strap-on. The pump began spinning up, but with no propellant in it, the speed of rotation quickly exceeded its design limits which caused it to rupture and allow RP-1 to leak out and start a fire which quickly engulfed the base of the launch vehicle. Titov and Strekalov could not see what was happening outside, but they felt unusual vibrations and realized that something was amiss. The launch control team activated the escape system but the control cables had already burned through, and the Soyuz crew could not activate or control the escape system themselves. The backup radio command to fire the LES required 2 independent operators to receive separate commands to do so and each act within 5 seconds, which took several seconds to occur. Then explosive bolts fired to separate the descent module from the service module and the upper launch payload shroud from the lower, the escape system motor fired, dragging the orbital module and descent module, encased within the upper shroud, free of the booster with an acceleration of 14 to 17g (137 to 167 m/s²) for five seconds. According to Titov, "We could feel the booster swaying from side to side. Then there was a sudden vibration and a jerking sensation as the LES activated".