The capsules were honeycomb Titanium with thin sheets of Titanium welded to each side of the honeycomb. The walls were about 2 cm thick and when you rapped on it, it was as solid as rock. No ring, no metal sound, no hollow sound. The sound was like knocking on a rock!
The inside was a control panel (mostly indicator lights) and a seat. You just went for a ride.
I have some souvenirs of the launch, and AFAIK, my name was the last to sign out before the launch and the first to sign in. The pad was still steaming.