Inspirations and additional sources
Cambias, James L. Designer's Notes, GURPS Mars in Pyramid Online.
     Canyon adventure, including elements for all 4 unstable shifts.
Cambias, James L. GURPS Mars, Steve Jackson Games.
     General backgrounds (all 4 Mars used); maps.
From the Earth to the Moon. Produced by Tom Hanks.
     Low-tech space exploration.

Shiftworld and all materials pertaining TM Michel M. Albert. GURPS TM Steve Jackson Games.