From the rulebook:

Mayday is a science-fiction game of small spacecraft in danger, distress, and combat. Using realistic vector movement and intriguing combat systems, Mayday presents a fascinating and enjoyable situation for hours of stimulating recreation.

Mayday is intended as an enjoyable game in its own right; it is also Game 1 for Traveller – GDW's role-playing game of science fiction adventure in the far future.