Purgatory Mount

An interstellar craft is decelerating after its century-long voyage. Its destination is V538 Aurigae ?, a now-empty planet dominated by one gigantic megastructure, a conical mountain of such height that its summit is high above the atmosphere. The ship''s crew of five hope to discover how the long-departed builders made such a colossal thing, and why: a space elevator? a temple? a work of art? Its...