Very easy achievement. It can be done in any mode from casual to veteran on the Ursa Major campaign level 2.
Simply rescue the animal friends that are entrapped in the enclosed area(there may only be one enclosed area and therefore you must explore the entire map). Once you do this a small bomb will appear on the screen and explode. A green aura should begin expanding and all you need to do is make sure that your entire ship is within the green part of the explosion and escape it. Your achievement should pop momentarily.