Step 6 Characterizing the Mission Architecture

Once we have established alternative mission concepts, architectures, and system drivers, we must further define the mission concepts in enough detail to allow meaningful evaluations of effectiveness. For concept exploration, the steps in this process correspond to the space mission elements. Figure 2-5 illustrates the sequence of activities and shows schematically the major interactions between the steps, as well as primary trade study areas and their interactions with main elements of the process. The steps are described below and summarized in Table 2-10.

TABLE 2-9. Identification of Performance Drivers for FlreSat. First-order algorithms are given to allow us to estimate the performance drivers. Definition of performance drivers may change as we create more detailed definitions of the system and system algorithms. Comparison of columns two and three shows that the performance drivers may depend on the mission concept used.

TABLE 2-9. Identification of Performance Drivers for FlreSat. First-order algorithms are given to allow us to estimate the performance drivers. Definition of performance drivers may change as we create more detailed definitions of the system and system algorithms. Comparison of columns two and three shows that the performance drivers may depend on the mission concept used.

Key Parameters

Rest Order Algorithm (Low-Earth Orbil)

Rrst Order Algorithm (Geosynchronous)

Performance Drivers

Observation Frequency

(Number of spacecraft)/ 12 hr

Scan frequency

Number of spacecraft for low orbit

Time Late

Onboard storage delay + processing time

Communications + processing time

Storage delay (if applicable)

Resolution

Distance x [(wavelength/ aperture) + control error]

Distance x [(wavelength/ aperture) + control error]

Altitude, aperture, control accuracy

Observation Gap

Cloud cover interval or coverage gap

Cloud cover interval or coverage gap

None

(weather dominated)

TABLE 2-10. Summary of the Concept Characterization Process. See text for details. See Rg. 2-5 for a typical process flow.

Step

Where Discussed

0 0

Post a comment