Even satellites are not immune to downscaling these days. A team of York university scientists has entered a competition to launch a "microsatellite," or rocket, into space.

    Led by Earth and Atmospheric Science professor Ian McDade, the York team has a proposal to join the race for space so they can study the Earth's permanent aurora ­ the glowing shell of gas around Earth's atmosphere called the airglow layer.

    The competition is sponsored by the Canadian Space Agency (CSA) which has narrowed the field from 16 proposals down to five: one for a rocket, and four for microsatellites. If York wins, it would be one of the few universities in North America to have its own spacecraft in orbit. The competition should be decided some time early in 1998.

    McDade says he has high hopes because the MESO project (Microsat Experiment for Sounding Oxygen) is simple and inexpensive. "It will also help shed light on the phenomenon of airglow," he says.

    The airglow layer ­ about 10 km thick­ forms a thin luminous shell around earth about 100 km above its surface. Although difficult to view from the ground, astronauts see it as a rich green/gray/orange coloration.

    Airglow is caused by excited oxygen atoms (normally joined, i.e., O^₂) being split apart by ultraviolet sunlight. When the split atoms recombine to form O^₂ again, the energy rich oxygen reverts to regular oxygen but, in the process, gets rid of extra energy by emitting light of various colours.

    The brightness of the airglow layer is proportional to the concentration of oxygen atoms in the atmosphere. By measuring airglow brightness scientists can determine the amount of atomic oxygen present. They can then develop detailed maps of the distribution of oxygen atoms in the upper atmosphere at various times. The maps will allow researchers to document how the air in the atmosphere circulates.