Farmech

The Farmech Project was a mission created by Earth in order to sustain the human population. It consisted of sending probes, like PIP-3R, into the reaches of space to scout for habitable planets. Mechs were created to help traverse terrain on alien planets and to assist the agricultural progress on these new planets.
Even though some settlers such as the Botanist left Earth as part of the project, it was eventually abandoned in favor of moving the human population to mars. The probes were left floating in space endlessly sending reports back to Earth, and the early settlers left to fend for themselves on these alien landscapes.
It is suggested by PIP-3R in the beginning of the game, that the player stole his starship and Mech from an old Farmech Project scrapyard.