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ESA Document - Emits - ESA

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s<br />

HMM<br />

Assessment Study<br />

Report: CDF-20(A)<br />

February 2004<br />

page 221 of 422<br />

Improvements to the arrays are made as follows:<br />

• Increase of panel length to 6.33 m; Individual panel size 6.33 m x 1 m<br />

• 15 active panels per wing; wing requires 16 panels for deployment system to function<br />

correctly, panel no. 1 to be spacing panel only.<br />

• Inclusion of the retraction/re-stowage capability; function already available, but not<br />

qualified.<br />

• Inclusion of a re-latching and release capability in the stowed configuration.<br />

An analysis of the loading applied to the solar array as a result of the propulsive manoeuvres<br />

shows that the deployed wing is unable to withstand the loading (see Table 3-48) and therefore a<br />

re-stowage capability is required.<br />

Solar Array Wing Mass<br />

Deployment System (Kg) Panel/Cells (Kg) Total (Kg)<br />

45.7 149.6 195.3<br />

CoM position 8 m<br />

Allowable Shear 25 N (Derived from Bending allowable, not actual shear)<br />

Allowable Bending 185 Nm<br />

Mass. Vehicle (Kg) Thrust (N) Acceleration ( m / s)<br />

SA Force applied at<br />

CoG/Shear Load<br />

SA Bending<br />

Moment<br />

Margin of Safety<br />

Bending<br />

TMI. 1 st Start 1363000 5200000 3.81511372 745.0917095 5960.733676 -0.968963552<br />

TMI. 1 st End 1084000 5200000 4.79704797 936.8634686 7494.907749 -0.975316574<br />

TMI. 2 nd Start 1045000 5200000 4.976076555 971.8277512 7774.62201 -0.976204631<br />

TMI. 2 nd End 766000 5200000 6.788511749 1325.796345 10606.37076 -0.982557653<br />

TMI. 3 rd Start 728000 3900000 5.357142857 1046.25 8370 -0.977897252<br />

TMI. 3 rd End 518000 3900000 7.528957529 1470.405405 11763.24324 -0.984273045<br />

MOI. 1 st Start 474000 1530000 3.227848101 630.3987342 5043.189873 -0.963316868<br />

MOI 1 st End 293000 1530000 5.221843003 1019.825939 8158.607509 -0.977324562<br />

MOI. 2 nd Start 277000 612000 2.209386282 431.4931408 3451.945126 -0.946407028<br />

MOI. 2 nd End 205000 612000 2.985365854 583.0419512 4664.33561 -0.960337331<br />

TEI. Start 165000 612000 3.709090909 724.3854545 5795.083636 -0.968076388<br />

TEI. End 82000 612000 7.463414634 1457.604878 11660.83902 -0.984134932<br />

3.3.8.3.2 Communications system<br />

Table 3-48: Solar array wing loads<br />

A number of antenna pointing mechanisms exist. A schematic of a typical boom mounted<br />

deployment and pointing mechanism for the TV antennas.<br />

For a complete 180° hemispherical coverage, the axial and azimuth axes shall rotate through<br />

180°.<br />

An analysis of the loading applied to the antenna boom as a result of the propulsive manoeuvres<br />

shows that the 3-metre deployed boom assemblies are highly loaded in bending (the analysis<br />

results are shown in Table 3-49). Three solutions are possible;<br />

1 Rigidly mount the antenna and APM on a truss structure- no deployment, pre-installed<br />

during LEO assembly<br />

2 Static or deployable boom with the deployment axis orientated along the load vector<br />

(large bending moment occurs across the hinge)<br />

3 Deployable boom with a re-stowage and latching capability

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