In the enclosed drawing, the hatches are just round circles, but in
reality they will probably be a bit D-shaped -- a circular hatch with one
edge straight to accommodate a hinge -- or square with rounded corners.
There are alternatives to hinges. On the space station the hatches
move on a yoke mechanism which guides the hatch so that it slides along the
wall of pressure shell instead of swinging into the airlock. That reduces
the swept volume of the airlock hatch, gaining more useful interior space
at the expense of additional weight. On Apollo, the Lunar Module had a
D-shaped hinged hatch. Between the Command Module and the Lunar Module,
the hatches were closed with simple removable plugs. The Command Module's
main hatch, on the side where the crew entered on the launch pad, was a
Out of all these alternatives, my guess is that the best choice is an
adaptation of the space station design. A square hatch with rounded
corners has an advantage over a circular design because it can move
through its own diagonal. Circular hatches can't do that. That feature
means we have more operational flexibility. A hatch over an opening which
sometimes sees pressure on one side and sometimes on the other can be moved
to the other side depending on the conditions. Theoretically, that makes
for lighter hatches and door frames. It also means we could move a hatch
from one location to another as we plug additional modules
onto the moon
Copyright © 2007 Artemis Society International, for the
contributors. All rights reserved.
This web site contains many trade names and copyrighted articles and images.
ASI Web Team
Submit update to this page.
Maintained with WebSite Director.
Updated Fri, Sep 18, 1998.