Satellite Configuration Design - Finite Element Analysis for Satellite Structures - page 12

straightforward. The answer of one depends on several or all of the solutions to the
others. Often, we cannot find the best answers to the above questions until we try
to configure the satellite. However, to start developing the initial configuration,
answers can be estimated to the above questions, so that the key components and
their critical characteristics may be identified. By doing so, a preliminary equip-
ment list, which includes information such as quantity, size, mass, and the required
power for each component, is generated.
Using this list, the launch vehicle's payload envelope, identified fields of view
for sensors and antennas, and basic packaging guidelines, arranging the compo-
nents, and tying them together with structural load paths can be begun. The
resulting configuration is just a starting point for a string of iterations. The process
of developing a preliminary satellite design is summarized in Fig. 2.1 .
The information needed to begin developing a satellite configuration is con-
cerned with all major design elements which have an effect on configuration. The
first significant element is the payload, which is the starting point for satellite
design and usually the heaviest components. It is characterized by its size, weight,
power, data rates, field of view, thermal interfaces, and other constraints. It
determines the satellite attitude, and most probably uses a lot of power. Another
element having great effect on a satellite configuration is the mission, which is
distinguished by its orbit, reliability, design life, operations concepts, and mission
constraints. Orbit defines satellite environments and power-gathering capabilities,
while reliability and design life influence the number of components and com-
ponent size.
Launch vehicle has very important effect on satellite configuration design. It is
characterized by environments and constraints which contain envelope, mass
properties, fundamental frequencies, and access. The stowed envelope can derive
the need for complex deployment mechanisms. Data relay and communications
also affect configuration design. They specify the frequency, data rate, hardware
losses, and receiver station characteristics. Antennas may need special locations
for fields of view, and the transmitter typically must be near the antenna. Another
element is attitude control approach, which is categorized into spin-stabilized, 3-
axis, and gravity gradient. The control types require different types of actuators
and affect the configuration in different ways. Subsystems have great influence on
satellite configuration design. Key components must be defined early, and minor
components can be added as the configuration matures. Schedule and cost limit the
development of technology, so risks, schedule, cost, and technical function must
be considered.
Table 2.1 describes a general process for configuring a satellite [ 1 ]. Because of
unique requirements and equipment, no single process applies to all satellites, but
this one should be effective for most programs. The products from this process are:
• Layouts of stowed and deployed configurations, showing the arrangement of
equipment and the main structural load paths
• An equipment list that summarizes quantity, size, mass, and power for each
component