Rendezvous with Rama by Arthur C. Clark

The “Rama” of the title is the starship, which is initially mistaken for an asteroid and named after the Hindu deity Rama. (By the 22nd century, we are told, scientists have run out of Greek and Roman mythological figures to name astronomical bodies after.) Asteroid 31/439 is detected by astronomers in the year 2131 while still outside the orbit of Jupiter. Analysis of its trajectory reveals that it it is moving very quickly (100 000 km/h) and in fact comes from interstellar space. Rama apparently comes from a nearby variable star which it left 200 000 years ago. Even more remarkable is its extremely rapid 4 minute rotation period and relatively large size. Rama’s artificial origin is confirmed by an unmanned space probe — “SITA” — launched from the Mars moon Phobos which makes a rapid 200 000 km/h flyby after a seven week voyage. The photographic images show a cylindrical object 16 kilometres wide and 50 kilometres long.