be ever
calculated by a responsible scholar) in less than 200 years."[72] A
European professor of medicine adds that any surge in human longevity at
this time is quite undesirable from the standpoint of making elderly
persons useful or cared for. "The problems posed by the explosive growth
of populations * * * are so great that it is quite reassuring to know
that biologists and medical men have so far been unsuccessful in
increasing the _maximum_ lifespan of the human species * * * and * * *
it would be a calamity for the social and economic structure of a
country if the mean lifespan were suddenly to increase from 65 to 85
years."[73]

Some anthropologists pessimistically wonder if man is going to prove
like the locust by populating himself into near extinction from time to
time.

Without subscribing to this view, one must nevertheless take notice of
the difficulties posed by population increase, not merely those of food,
shelter, education, and the like but also those resulting from cellular,
cramped, close living.

Whichever phase of the problem is studied, it seems not unreasonable to
conclude that space research will help find a solution. New ways to
produce food, new materials for better shelter, new stimuli for
education--all of these are coming from our space program. As for the
matter of adequate living room, space research may result in ways to
permit an easy and efficient scattering of the population without
hurting its mobility. This might result from the development of small
subsidiary types of craft, or "gocarts," originally designed for local
exploration on other planets. Such craft, whether they operated by air
cushion, nuclear energy, gravitational force, power cell, or whatever,
conceivably would permit Earth's population to spread out without the
need for expensive new roads--which, by the way, take millions of acres
of land out of productive use.

A development of this sort, together with new power sources to replace
the fossil fuels on which factory, home, and vehicle now depend, might
also all but eliminate the growing smog and air-pollution blight.

_Water shortage_

A direct result of the population increase, multiplied by the many new
uses for which water is being used in home appliances, etc., and plus
the greatly increased demand for standard uses such as indoor plumbing,
irrigation, and factory processing, is the likelihood that water
shortage will be high on the list of future prob