Check out this way cool huge vacuum chamber that NASA uses to test spacecraft. This from the Space Power Facility in Sandusky Ohio (near Cedar Point). One of the many reasons why going to space is expensive!!

The Aluminum Test Chamber is a vacuum-tight aluminum plate vessel that is 100 ft. in diameter and 122 ft. high. Designed for an external pressure of 2.5 psig and internal pressure of 5.0 psig, the chamber is constructed of Type 5083 aluminum which is a clad on the interior surface with a 1/8-in. thick type 3003 aluminum for corrosion resistance. This material was selected because of its low neutron absorption cross-section. The floor plate and vertical shell are 1-in. (total) thick, while the dome shell is 1 3/8 in. Welded circumferentially to the exterior surface is aluminum structural T-section members that are 3-ft. deep and 2 ft. wide. The doors of the test chamber are 50 X 50 ft. in size and have double door seals to prevent leakage. The chamber floor was designed for a load of 300 tons.