Bob:
Shown in this message is a picture of the revised module
design that you and I have been working on in the last few days. The revised
cover has not yet been done but its features are implicated in this current
view. The machined base plate has robust beams around three sides. Further,
there are stiffening beams machined on the bottom side of the baseplate. The
side to side dimension of the baseplate is shown at 141mm, reduced from its
previous 147mm. This step was needed to accommodate the cover screw heads now
on the side of the module.
Shown also is a revised connector plate, which is increased
in width from the previous 122mm to the 141mm of the baseplate. This should
ease the connector space issue a little as the cover PEM nuts have accordingly
been moved out leaving a 125mm wide clear space for connector activity, an increase
from 106mm.
The PCB is unchanged, however its standoff posts are now 6.4mm
(1/4 inch) from the previous 4.8mm (3/16 inch), a step needed for connector
plate screws.
The cover will slide over the assembly shown and it will
have only one flange, along the rear side. The long sides will use screws
placed into the edges of the assembly (formerly a flanged side). This means
that there will not be mechanical loading on the baseplate caused by irregular flange
bends, as in the present cover design.
Regarding this design of module, the PCB access has been
fully maintained, but the cover cannot be removed while the module is installed
into the spacecraft, a feature that had been planned with the current design.
Discussion is invited.
