Master Thesis - OUFTI-1

Figure 5.8: Frame rotation
The calculation of the steady state accelerations in the CubeSat frame is presented in
Equation 5.3.1.
⎛ ⎞ ⎛
⎞ ⎛ ⎞ ⎛ ⎞
a X, CubeSat 1 0 0
2.4 2.4
⎝a Y, CubeSat
⎠ = ⎝0 cos (10 ◦ ) −sin (10 ◦ ) ⎠ × ⎝ 2.4 ⎠ = ⎝ −0.1756 ⎠ (5.3.1)
a Z, CubeSat 0 sin (10 ◦ ) cos (10 ◦ ) 12.6 −12.8253
Owing to the particular case which is considered, the weight of the two other CubeSats
placed inside the P-POD must be added to these acceleration. The maximal acceptable
mass for one CubeSat is 1 kg. So, the forces acting on the four feet of OUFTI-1 base plate,
due to the two CubeSats placed above it, are calculated in Equation 5.3.2.
F = m × g × a quasi−static = 2 × 9.81 × 12.8253 = 251.64 N ≈ 252 N (5.3.2)
which lead to a force of 63 N on each foot along the Z axis of the CubeSat frame.
It is important to note that the accelerations considered in this analysis occured at
dierent phases of the ight (the maximal longitudinal acceleration is reached at the third
stage's maximal acceleration and maximal lateral accelerations are reached during the lifto
and under the ight maximal dynamic pressure). So, the resulting model is conservative,
which brings an additional security with regard to the results.
An illustration of the complete loading state (in the CubeSat frame) is given in Figure
5.9.
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