Envelope: Assume the spacecraft fits within a required launch-vehicte-fairing envelope (found in Table 18-7 or Fig. 18-8). Also assume that satisfying rigidity requirements will keep the spacecraft's deflection from violating the fairing's dynamic envelope.

Mass: Assume the 2,000 kg is the total spacecraft mass, including an allocation for structure.

Load Factors: Axial = 2.5 (steady-state) + 4.0 (transient) = 6.5, Lateral = 3.0 (Representative load factors can be found in Table 18-9.)

Rigidity: The first axial frequency of the spacecraft must be above 25 Hz. The first lateral (bending) frequency must be above 10 Hz. (See Table 18-9 for typical values.)

Pressure: An internal venting pressure similar to Fig. 18-9 has a maximum value of 6,899 Pa.

Factors of Safety: 125 (ultimate) and 1.10 (yield) according to Option 2 of Table 11-54.

Material Properties: 7075 aluminum is chosen.

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