Several of my Rovers are visible in the right hand screenshot. The GUI lets you view and access Buildings, Rovers, Weapons, Armour, Gear, Modifiers and raw Jitters. While you may be tempted to just build everything you can find, some thought is needed. You need to balance the cost of an item against the usefulness of that item. The big challenge is to build up your base and items.
Nothing is ever free in life of course.
It will cost TU's to build items, and TU's to keep things running. If you run out of Transium, your in deep dodo. Thus, not only do you need to protect your base, your Wells need guarding, too. My other 2 Wells are also guarded. If you are going to attack, Wells tend to be the number one target.