Escape velocity
If escape velocity from Earth is ~ 11.3 km/sec, then an impetus of 68.6 m/s is a mere 1/200th of the kick for launch.
If your method introduces more than 1/200th risk cf. a conventional launch, then it is not worth considering.
I suggest that you do more work on reliability, and think whether a static launch from Kilimanjaro or Mauna Kea will be better than a boosted launch at se level.
Look up Lake Titicaca, when you have spare time...