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Presenter: Bjarni V. Tryggvason - Canadian Space Agency
Supervisor:

Date: Thu, March 20, 2003
Time: 19:00:00 - 00:00:00
Place: Centre for Innovative Teaching, Room 105

ABSTRACT

One of the main opportunities that the International Space Station offers is the ability to conduct experiments in the near free fall environment, which reduces disturbances due to convection, buoyancy and sedimentation by several orders of magnitude compared to that in ground based experiments. Because of the high activity level on the ISS and the station dynamics, it is not possible to eliminate the vibrations of the station structure itself. Experiments that require true micro-g disturbance levels will have to make use of isolation systems, several of which have flown. There is still an active debate on just how clean an environment is required. The Canadian Space Agency (CSA) has supported numerous experiments on the Russian Mir space station and on the US space shuttle to look at sensitivity to milli-g accelerations. Results of these experiments have recently been published and show sensitivity to vibrations levels typical of what is found on the shuttle and the Mir. In this presentation the effects of these low level vibrations (frequency range 0.1 Hz to 100 Hz) on diffusion are illustrated based on several experiments. The experiments conducted include approximately 150 runs examining diffusion in liquid metals, several that examined nucleation in glasses, and another that examined vibration effects on Brownian motion.

These experiments were conducted using the Microgravity Vibration Isolation Mount (MIM) developed by the presenter at the CSA. The MIM enabled performance of experiments that could directly examine the effect of milli-g vibration levels on basic fluid science experiments, and has essentially led to a new class of experiments for the ISS.

Bjarni Tryggvason has about 4,000 hours of flight experience, holds an Airline Transport Rating and has been a flight instructor for 10 years. He is currently active in aerobatic flight and is qualified as Captain in the Tutor jet trainer with the Canadian Air Force. Tryggvason served as a Payload Specialist on STS-85 (August 7-19, 1997), a 12 day mission to study changes in the Earth's atmosphere. During the flight, his primary role was testing MIM-2 and performing fluid science experiments designed to examine sensitivity to spacecraft vibrations. He currently splits his time between training and technical duties at the Johnson Space Center in Houston and the Canadian Space Agency in Montreal. At the CSA he provides support to the Microgravity Science Program which manages science payload development for the ISS. He also serves as a CSA representative on the NASA Microgravity Measurement Working Group and on the International Space Station Microgravity Analytic Integration Team.