Viewpoint: Yes, the ISS provides an effective platform from which manned exploration of the solar system can begin, and it represents an important model for international cooperation.

Viewpoint: No, the ISS is a poor use of valuable space exploration funds, and its low-earth orbit can do little in the way of generating creative new strategies that will make the exploration of distant locations in the solar system more feasible.

Space exploration must take place first in our imaginations. There, dreams and plans can flourish unencumbered by the drab realities of political, financial, and technological constraints. To assess the future of man's activities in space, we must ask both if we are moving toward the ultimate satisfaction of our...