Mission beyond the Ice Cave: Atlantis-Mexico-Zotola

In this sequel to Mission of the Galactic Salesman, a group of teenagers visit an ice cave in Antarctica. There they meet two young, lively fellows, having arrived in their Velosa cruiser craft from a planet around the star Al Nitak in the Orion star system. They are descendants of the people of Atlantis, and they are visiting Antarctica to research their Atlantean heritage. They travel home with them in their vehicle-craft to a land they call Zotola, and there they soon discover a buried crate of holographic metal plates in an ancient galactic dumpsite. The galactic salesman also comes forth ad offers another mission. The Orion star system needs to be added to their telephone system, and communication is mysteriously blocked from Earth. Can the teenagers with the help of their new friends from Zotola pinpoint the problem and clear the mysterious block?