Algor Software Helps Ensure Smooth Launch of Satellite with Optical Indicating Device

Sometimes, getting a device into place is more than half the problem and an important design and analysis consideration. Transport-related random vibrations can be a significant issue if your design will be conveyed by truck or train. Imagine how much more significant these issues are if you are analyzing a device contained in a military communication satellite that will be launched from a NASA space shuttle!

John Sfakis of Engineering Technologies in Long Island, NY, analyzed such a device with Algor's Linear Stress and Random Vibration Analysis Software to ensure that a 8-12 minute launch cycle would not cause significant damage or displacement. The optical pitch and roll indicating device would then keep the satellite on course above the earth's atmosphere for approximately 30 years.

John Sfakis of Engineering Technologies in Long Island, NY, analyzed such a device with Algor's Linear Stress and Random Vibration Analysis Software to ensure that a 8-12 minute launch cycle would not cause significant damage or displacement. Mr. Sfakis is an independent consultant who has worked on a wide variety of engineering projects from shelf brackets for Stanley Tools to complex electronic packaging for aircraft, where weight savings are critical. Mr. Sfakis uses Algor software to predict failures before they happen and optimize designs for safety and adequate customer usage.

Optical Indicating Device Keeps Satellite on Course

The optical indicating device is designed to sense the horizon of the earth and keep the satellite on course. The device monitors the pitch and roll of the satellite and makes adjustments to keep the satellite from descending into the earth's atmosphere before its working life is complete.

Once in space, the device would not be subjected to any kind of vibration. Sound does not travel in the vacuum of space and the satellite will not be in contact with any objects which might vibrate. However, engineers were concerned about the effects of linear stress and random vibration during the 8-12 minute launch cycle from a NASA space shuttle. If the optical indicating device were to be damaged, the satellite might not dependably maintain the altitude critical for reliable operation over its planned 30-year life.

A combined random vibration and linear stress analysis with quasi-static load cases was necessary to ensure that the device would withstand the launch procedure.

Designing and Analyzing the Plate/Shell Model

The optical indicating device consists of three printed circuit boards (PCBs), an optical sensor and an outer housing. Mr. Sfakis began by creating a wireframe of the device in Superdraw II. The wireframe was imported into Supersurf for initial surface meshing. That surface mesh was then optimized with Merlin Mesh Enhancement Technology. The uniformity of the mesh created by Merlin is important to ensure an accurate analysis.

Three separate analyses were conducted to determine the vibrations in the X-, Y- and Z-directions, respectively. Linear stress loads were applied to the device's housing in each case. The results indicated that the optical indicating device would withstand the stresses and random vibrations associated with the launch procedure.

Launch Was Successful!

The military communications satellite containing the optical indicating device that Mr. Sfakis designed was successfully lauched from the space shuttle last month.