In assessing the _practical_ values of space exploration it does not
seem logical to limit considerations to those values which are immediate
or near-future ones. The worth of a present activity may be doubled or
trebled because of its long-range potential.
Such values may not be practical within the context of today's usage,
but they may be extremely practical if we are willing to concede that
those of us living today have an interest in and a responsibility for
what happens on Earth in the decades and centuries to come.