Back to the Frequency Response Page. Back to the MOLA Mechanical Analysis Page.
This page is maintained by Ryan Simmons, at Ryan.Simmons@nasa.gov.This page was last updated on January 19, 1996.
The MOLA Frequency Response Analysis uses three separate input specs, one for each of the three orthogonal axes. This is done because the launch vehicle, a Delta II rocket, has different sine vibration loading environments in different directions. Below are the input specs for each axis. These inputs represent the sine vibration being input to the instrument through the spacecraft. The levels are all protoflight because some MOLA-2 components were significantly redesigned from MOLA-1.
The three specs given below show a significant drop in level at 60 Hz. Generally, sine vibration is only a problem below 60 Hz. However, the MGS project decided to test up to 100 Hz. Because MOLA's first natural frequency lies between 60 and 100 Hz, the acceleration input level was dropped. It can be dangerous to an instrument to vibrate at high levels through a natural frequency. After the analysis results are obtained, it was determined that even the MOLA-1 levels were too high, and the spec to be used for MOLA-2 testing will also be notched (see the force response results).
Clicking on the table's caption will bring up a graphical chart of the input spec.
| Freq. (Hz) | Level |
|---|---|
| 5-12 | 0.75 in. DA* |
| 12-60 | 6.0 g |
| 60-100 | 0.5 g |
| Freq. (Hz) | Level |
|---|---|
| 5-12 | 0.75 in. DA* |
| 12-60 | 6.0 g |
| 60-100 | 0.7 g |
| Freq. (Hz) | Level |
|---|---|
| 5-12 | 0.75 in. DA* |
| 12-60 | 6.0 g |
| 60-100 | 1.5 g |
Back to the Frequency Response Page. Back to the MOLA Mechanical Analysis Page.This page is maintained by Ryan Simmons, at Ryan.Simmons@nasa.gov.