The Microgravity Emissions Laboratory (MEL) was developed for the support, simulation, and verification of the International Space Station (ISS) microgravity environment. The acceleration emissions generated by various operating components of ISS, if too large, could hinder the science performed on ISS by disturbing the microgravity environment.

Typical test components are disk drives, pumps, motors, solenoids, fans, and cameras. Other MEL test articles have included spacecraft onboard electric power systems, optical measurement systems, and crystal growth experiment package assemblies. Electric or fluid-driven support systems that operate the hardware are customer supplied.


Above: MEL mechanical setup

The MEL is a low frequency (0.15-0.4 Hz) isolator that is a pendulous-based system. The isolation system suspends the measurement apparatus with the attached test unit by a long cable. The lateral frequencies are established with the pendulum and the vertical mode is lowered by the isolation system mechanism. The mechanism reduces the system's vertical frequencies to approximately 0.4 Hz by bearing the weight of the payload through a semipassive frictionless air spring.


Above: Mass-moment-of-inertia determination using bifilar pendulum method.

MEL was developed for the Fluid Combustion Facility through the Microgravity Sciences Division (MSD). The laboratory is located in the Structural Dynamics Laboratory (SDL). Engineering models of the FCF Optics Bench and Air Thermal Control Unit have been tested in FY 01.

These test are done on operating equipment; therefore pre-test planning is a must. All umbilicals, services such as water, power etc. are provided by the customer unless alternate arrangements are made. Due to the isolation required, umbilicals and support service lines need to be long (5-10 meters). The operations matrix is also provided by the customer. Any non-standard fixturing issues will need to be resolved as test planning begins.