Just because I had problems with it, to complete the last cargo mission into space, I used: Mark-I Head Section, MK-V Body Section, MK-III-G Fins, MK-IV-FB Engines, MK-V Boosters, Radar-2, Cooling System, Gatherer, and Refueling.
This may be obvious, but the main mission gold star times are only really possible if you speed through the level and just kill the boss. Forget about the side objectives. Just rush the boss and kill him quickly.
 "Into Space 2"){kind=icon}
 "Mechanical Commando 2"){kind=icon}
 "Level Up!"){kind=icon}
 "Dungeon Cleaner"){kind=icon}