inexplicable recurrent movements of an object across the night sky following a thunderstorm.

It was spring and a thunderstorm was waning.  The time was just after sunset and the electricity had gone off.  On a portable radio we heard that a tornado has been sited to the south of our location.  The rain had stopped and we decided to watch for any evidence of the tornado and proceeded to the roof as it offered our best vantage.  The cloud cover was clearing and moving west to east and the sky was dark and clear.  Without electricity we remained on the roof long after the weather settled.  We were just observing the sky as we often did when possible.  Nothing much was happening until I observed a light, much like Telstar I had observed as a child, moving across the sky coming from the north.  It was heading in a southerly direction at a steady pace when it made a ninety degree turn to the east in an abrupt and continuous movement.  It maintained an easterly course until no longer visible to the naked eye.  A few minutes had passed and I spotted the lig! ht again this time heading east to west along the same general path as earlier.  Again it made a ninety degree turn this time to the north.  Again the maneuver was steady, abrupt and continuous.  Hoping it would return we continued to watch the sky.  After a few minutes, I observed the object coming from the north and heading south and again it changed direction in a ninety degree movement heading east.  I tried to point out its location to my partner but it was so dark you literally could not see your hand in front of your face.  It continued east until I lost sight of it.  I waited for the object to return but it never did.  After about thirty minutes we finally climbed down from the roof and called it a night.  I can’t explain what I witnessed but I can’t imagine it was anything naturally occurring.  It seemed to have purpose and the ability to carry out difficult if not impossible maneuvers.  Although this occurred over forty years ago I can recall it as if it were yesterday.
Witness indicates that the date of the sighting is approximate.  PD