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April 18, 2022 "Attaining Microgravity Environments in Space: Active Vibration Isolation on Space Shuttle and International Space Station"

  • 4:00 p.m.
  • Room: 100 Hancock Hall
  • Dr. Don Edberg, California Polytechnic State University 
  • Faculty Host: Dr. Pat Artis

Abstract: When originally conceived, the International Space Station (ISS) was intended to provide a pristine microgravity (µg) environment for on-board experimentation. However, disturbances from crew, on-board mechanical systems (solar array and radiator positioning), and other equipment was predicted to exceed the required µg acceleration levels.

At the time, McDonnell Douglas (MDC) was conducting independent R&D on microgravity vibration isolation for orbiting science research and proposed a demonstration flight experiment to colleagues at Marshall Space Flight Center (MSFC). The flight experiment would use some existing hardware from a helicopter-mounted optical sensing system and would have two “regimes” of µg isolation control: a low-frequency centering system and a high-frequency acceleration attenuation system.

In December of 1994, MSFC informed MDC of an opening of a middeck locker space in the United States Microgravity Laboratory flight 2 (USML-2) to be launched in Sept. 1995. Thus began a six-month program to design, build, test, and deliver a microgravity isolation system, almost unheard of within a large corporation like MDC, and NASA.

The presentation explains the principles of vibration isolation, the difficulties associated with bringing these to practice, and the development of STABLE, an acronym for the Suppression of Transient Acceleration By Levitation Experiment, the world’s first active µg isolation system in space. Results of the STABLE flight on USML-2 will also be presented, and will include key lessons learned about filtering, aliasing, and data acquisition.  You will then learn about the competition between MDC and Boeing to develop isolation systems to be deployed on the International Space Station (ISS). The Boeing system was ultimately selected, but initially suffered from a performance shortfall due to umbilical cables between the ISS and the isolated equipment that were not flexible enough. The author was summoned to assist with the redesign of these umbilical cables, and some of the interesting aspects of the redesign, testing, and implementation of the improved umbilicals will also be presented. 

Bio:  Dr. Donald Edberg received the 2019 California Polytechnic Pomona Provost's Excellence in Teaching Award. Dr. Edberg is the author of a textbook entitled Design of Rockets and Space Launch Vehicles, published by the American Institute of Aeronautics and Astronautics (AIAA) in October 2020.  He has taught many courses to include undergrad senior flight vehicle design capstone sequences in launch vehicle design, spacecraft design, and aircraft design; astronautics, advanced dynamics, vibrations & flutter, space environment, and systems engineering. Also, taught introductory aeronautics, propulsion, gas dynamics, machine design, statics and dynamics, graduate-level engineering mathematics and developed three one-year undergraduate senior flight vehicle design capstone sequences in launch vehicle design, and aircraft design.