I played this scenario today with only two players and had success. I played the Navigator while my friend played the Terminator. It wasn't that hard; I stayed on top of the corruption cards in the Sol tier while the Terminator leveled up and eventually punched Abbadon in his face.
Your chatacters that can deal with corruption have to go to the Sol Tier practically at game start. Also, don't forget you can spend your faction symbols as two influence to pay for items or the tiles where you can boost your rolls; they're earned back fast enough on the side board.