By 2050, America will have permanent occupied bases first on the moon and then Mars. These bases will be for planetary exploration, science, observation and long term National Defense. For occupied planetary surface bases, there are the problems of logistics, communication and habitation. Planetary surfaces, such as Mars, consist of fine, unknown soils that may be hazardous to human explorers. Because EVAs will bring soil into the Astronaut's habitat, if these soils contain as little as 0.01% silica, then the habitat design may become difficult. To keep the respirable quartz particle level within acceptable health limits, then extensive filtration, power and additional habitat weight will be required. Discussed are ways to limit the amount of dust entering said habitat. (C) 2002 Published by Elsevier Science Ltd.