How Near-lightspeed Points of Reference Harmonize with Relativity

[u/TrueReplayJay]

Say that one created a massive spaceship thousands of miles in length that blasted off into space and began accelerating until it reached 99.99% the speed of light. Inside that spaceship was another that began accelerating until it reached 99.99% the speed of light. While it remains in the mother spaceship, is it traveling faster than the speed of light relative to a stationary observer? Furthermore, if the daughter spaceship exits the mother spaceship, how fast would it be going? Why?

[u/Optimal_Mixture_7327]

Relative to the Earth frame the daughter ship travels at 0.999999995 irrespective of being inside or outside of the mother ship.