Movie begins with an ufo blowing up research facility in the Artic. Now story moves to the desert where mother and son, of scientist missing from the research facility, are living. Son acquires a floating sphere as a companion. Later they are telepathically called to a mesa where the saucer lands and the scientist walks off the saucer.

Sounds like The Alien Encounters. Here is a snippet off someone's review of the film. It seems to match your description:
.....After recently re-watching the obscure, nigh forgotten sci-fi flick "The Alien Encounters" (1979, dir. James T. Flocker), I'm happy to know that I was NOT hallucinating a film about a silver spherical alien probe named Charlie that hovers around the desert, observing a scientist and teenage boy hiking nearby as they search for the "Betatron", a machine to prolong human life invented by the boy's late scientist father......
The Alien Encounters (TV Movie 1979) - IMDb