May 24, 2011

Dynamic Simulation Capabilities of MSC Adams Used in Full Throttle for Satellite Launch

MSC Software Corporation today announced that the Rotorcraft Systems Engineering and Simulation Center at the University of Alabama in Huntsville has launched a satellite, which is now in orbit around the earth, using the advanced dynamic simulation capabilities of MSC Adams.

The satellite's initial goal of obtaining the Certificate of Flight Readiness (CoFR) required that several risk reduction analyses be performed. One of these analyses involves evaluating the probability of re-contact between the space vehicle and the launch vehicle during deployment.

This analysis is a rigid body problem, which requires evaluating the induced rotation rates of the two rigid bodies as well as the changes in their relative velocities due to the deployment mechanism. These factors along with the geometry of each rigid body are used to evaluate the minimum expected clearance between the space vehicle and the launch vehicle.

In order to evaluate the minimum expected clearances, the system was modeled and analyzed using MSC Adams. In order to model the system three things had to be captured in Adams/View: mass properties of the two rigid bodies, geometry of each rigid body, and spring properties of the deployment mechanism.

A low fidelity envelope of the mechanical model was created, exported from the project's CAD software, and imported into Adams to provide the rough geometry of the space vehicle. The launch vehicle was modeled in a similar manner for the Lightband™, a commercially available satellite separation system manufactured by Planetary Systems Corporation. In addition to the Lightband™ model, simple envelopes were added to model areas that were dedicated to space vehicles that had not been deployed yet.

The deployment mechanism used was a mechanical Lightband™ with a full complement of 34 springs. Each of the springs was modeled according to Lightband™ drawings and specifications with respect to position, spring constants, and length.

First the model was checked by subject matter expert Clay Colley using hand calculations to verify correct construction of the model. The model was also compared to data collected by the Lightband™ manufacturer during testing of the mechanical Lightband™ with a mass simulator.

After the model was validated, Adams/Insight was used to develop a Monte Carlo simulation that included variability to key parameters such as spring strengths, the center of mass and each rigid body's inertial parameters. Upon execution the analysis provided a range of possible separation velocities and rotation rates and consequently a range of expected minimum clearances during separation.

The minimum separations and maximum rotation rates as well as expected separation velocities were used by the program to determine that the risk of re-contact was very low and well within the acceptable range.

"I have been using MSC Software's products including MSC Nastran since 1987, and I have always been impressed with the company's quality of software and support services. Casey Radigan from MSC Software provides my office with a level of service and support that is unmatched within the analytical software community, said Edward Clay Colley, Principle Research Scientist at the University of Alabama. "With the software products, we are able to train our student employees while working on real-world aerospace projects. The level of exposure these students receive while using MSC Software products allows them to enter the workplace with a greater appreciation of what is required to design an aircraft, spacecraft, or launch vehicle."

"We are very enthusiastic to be involved in space and satellite design projects like this one at the University of Alabama," said David Yuen, Senior VP of Americas at MSC Software. "We strive to provide top-notch support to our valuable network of university and research customers, and continue to empower new research and development initiatives so projects can deploy with little risk and the highest possible success rate."