According to Dr. Candle on the Orientation film, Station 3 was originally constructed as a laboratory where scientists could work to understand the unique electromagnetic fluctuations emanating from this sector of the island.
But not long after the experiments began there was an incident. And since that time the following protocol has been observed: every 108 minutes the button must be pushed.
Locke became disgusted with pressing the button, but Mr. Eko had taken over. Locke got Desmond to fake a lockdown with Eko on the outside. Locke destroyed the computer and the hatch imploded. It is unknown how those who were inside escaped.
In 1977, Daniel wants to stop the energy that is going to be released at the Swan site, because once the energy is released, then Dharma will have to build the hatch and push a button every 108 minutes. Then Desmond will fail to the push the button and the plane will crash. Then Daniel and Charlotte will come on the freighter. Daniel wants to stop that chain of events from happening by detonating the hydrogen bomb, but before he can, he's shot by Eloise. (Ep: 5x14, The Variable)
During Dharma times, we see the construction site for the Swan, led by Stuart Radzinsky, and Juliet is pulled into the hole, where she detonates the bomb. Kate, Jack, Sawyer, Miles, Jin, Hurley, and Sayid are blown back to the present, where they see that the hatch had been build and was imploded (Ep: 6x1, LA X).