Satellite Structural Design - Finite Element Analysis for Satellite Structures - page 56

Fig. 3.2 Location of
fastening studs and interface
bolts

4 holes for SC/LV interface bolts

8 holes for fastening studs

Selection of the number and location of fastening studs and interface bolts
depends on the load path shape and structural modules configuration. For Small
Sat, the main load path is a square cross-section with 525 mm side length, so the
suitable number of fastening studs is four, six, or eight studs. To provide sufficient
stability, using four or six studs is not acceptable. Therefore, eight studs are
selected to connect the structural modules. Each side of the main load path con-
tains two studs. The locations of the fastening studs are designed to provide
symmetry and regularity in load carrying. The same requirements are required for
designing the interface bolts. Four bolts are used to connect the satellite to LV
adapter or transportation container. Therefore, four steel bushes are mounted on
the base plate to work as an interface between the satellite body and launch vehicle
adapter. Figure 3.2 shows the arrangement of eight fastening studs and the location
of four interface bolts between the satellite base plate and launch vehicle adapter or
transportation container.
To determine the final dimension and suitable material for the fastening studs, a
close look should be made at the studs function. The major objective of the
fastening studs is connecting structural modules in accurate alignment during all
phases of the satellite's service life. To provide this objective, there are two
essential conditions that must be met. The first is to provide accurate assembly of
the structural module. This is started from the manufacturing process by assuring
the accuracy of the relative locations of the fastening holes in each structural
module, and ended by taking all precautions during the assembly process. The
second condition is to prevent relative lateral sliding between structural modules
during all phases of satellite operation. This condition can be met by applying a
specific amount of longitudinal compression to the satellite during assembly
process to provide sufficient lateral friction. This is done by applying a specific
torque on each stud.