Fundamental lateral mode frequency of a spacecraft is determined experimentally by performing a base excited vibration testing. For the above vibration testing, the spacecraft is mounted on the slip table of the shaker system. It is shown in this work that even if the test fixture is quite stiff, the fundamental lateral mode of the spacecraft can be influenced by the slip table system. The frequency obtained in the test is lower than the base fixed frequency. In this mode, even though the test fixture does not undergo bending, the slip table undergoes bending resulting in rotation of the test fixture. The stiffness of the bearing and the bending stiffness of the slip table are the causes of reduction in stiffness. A mathematical model that represents this behavior is developed for two typical shaker-slip table systems, one having a capacity of about 150 kN force and the other about 300 kN force. It is seen that the test system can cause a drop of about 3 Hz for a 3000 kg class of spacecraft, while using 150 kN shaker system. This is quite significant as their frequencies are in the range of 12–15 Hz.

航天器的基本横向模式频率是通过执行基础激励振动测试通过实验确定的。对于上述振动测试，航天器安装在振动器系统的滑台上。这项工作表明，即使测试夹具非常坚硬，航天器的基本横向模式也会受到滑台系统的影响。测试得到的频率低于基础固定频率。在这种模式下，即使测试夹具没有弯曲，滑台也会弯曲导致测试夹具旋转。轴承的刚度和滑台的弯曲刚度是刚度降低的原因。代表这种行为的数学模型是为两个典型的振动台系统开发的，一个具有约 150 kN 力的能力，另一个具有约 300 kN 力的能力。可以看出，该测试系统在使用150 kN激振器系统时，对于3000 kg级的航天器可以引起约3 Hz的下降。这是非常重要的，因为它们的频率在 12-15 赫兹的范围内。