Rapidly deployable modular shelter system

A purlin connection assembly comprising:

• a purlin comprising a protrusion, the protrusion comprising a neck and a flared head;
• a frame segment comprising
• an interior,
• a slot comprising a first end and a second end, wherein a height of the first end is at least as great as a height of the flared head, and wherein a height of the second end is less than the height of the flared head and at least as great as a height of the neck;
• a first button hole and a second button hole, the first button hole vertically aligned with the first end, a distance separating the first button hole and the second button hole being greater than a width of the purlin;
• and
• a spring comprising a first button and a second button, the spring compressingly disposed in the interior of the frame segment, wherein the first button and the second button are biased to extend outwardly through the first button hole and the second button respectively to project out of the frame segment, and wherein the first button and the second button are rigidly connected whereby depressing the second button effects inward retraction of the first button.