Very high altitude, high intensity flashing light that moved away from the earth and out of site in under 10 seconds.

I am a long time “we are not alone”, phenomena observer since my first experience in 1970.
On June 3, 2019, just after midnight, I was lying on a lounge chair in my back yard observing stars when a white flash of high intensity light appeared directly above me.  Only catching the last glimpse of the light as it went out, I kept focused on the area the flash came from.
Approximately 3 seconds later, another flash appeared, only this one was a bit lighter in intensity yet still very bright and only lasting 1 second before going out.  Another few seconds and another flash only this one was much less in intensity and still lasting about 1 second before going out.  The last flash came a few seconds later and it was hardly noticeable being very dim.  Then the show was over.
A booster rocket perhaps firing bursts to get out of our galaxy?..