On the issue of man in space and the letter by Gregory H. Kuenning (Feb. 22), I also am an engineer in the aerospace sector. I have been so engaged since 1956. I worked on the first Atlas, the first Centaur and the second-generation Centaur. More recently I have been involved in other unmanned launch systems.
Our trip to the moon was an unparalleled triumph and it fueled my hopes for further conquests in the foreseeable future. In more recent years my optimism has waned primarily for four reasons.
First, it appears that man is not biologically suited to live for extended periods in the absence of gravity.
Second, chemical propulsion systems are totally inadequate for even interplanetary travel. They are out of the question for interstellar voyages.
Third, the cost of putting a pound of payload into space is incredibly high. Only the richest nations can afford it now and as the pressures of increasing population are felt more strongly by everyone the rich also will be hard pressed to find the funds.
Finally, we must face the fact that, beyond a space station, there appears to be no economic incentive to go anywhere in the solar system. The moon and planets are biologically dead and do not appear to harbor any minerals that would justify colonization. For the time being exploration for the sake of science, a very valid objective, should be left to unmanned probes. Even the economic incentives for a manned space station may be meretricious at best. A careful analysis would probably show that, beyond learning about the effects of the environment on the human organism, they could be more efficiently accomplished by robotics.