There may well be good scientific reasons for John Glenn’s return to space in October aboard the shuttle Discovery. The effect of weightlessness upon his 77-year-old body and mind could provide valuable insight into the aging process, the information gleaned during the 10-day mission could help medical science solve the riddles of osteoporosis, immune-system deterioration, mental decline and other maladies of the elderly.

The best reason, though, has nothing to do with bone growth, disease or senility. It has everything to do with adventure, challenge and inspiration.

If science can learn from sending an elderly person into space, there can be no better candidate than the Marine pilot/astronaut/senator. Glenn has kept himself in superb condition and his extensive annual physicals provide a solid baseline of information for researchers.

But anyone who remembers 1962 knows why it must be Glenn; the tiny Friendship 7 capsule; the explosion-prone Mercury rockets; the agonizing delays; the astronaut’s terse yet awestruck commentary during his three brief orbits; the fiery, harrowing re-entry; the entire planet glued to transistor radios and black-and-white TVs for four hours and fifty-six minutes; the re-emergence of America as a contestant in the race for space. Glenn was a hero 36 years ago. The world is not so overstocked in heroes that it can afford to let one slip through its grasp.

At the same time NASA picked Glenn as its first elderly astronaut, it also said Idaho teacher Barbara Morgan will resume training and be placed on the roster for a later shuttle flight. Critics who dredge up the tragedy of the original teacher in space 12 years ago should recall that Christa McAuliffe and her six comrades did not die because of anything they did wrong — the Challenger blew up because of expediency and cost-cutting on the ground.

Now, as in 1962 and in 1986, there are those who say space travel is too risky — let machines do it, they say. Pure technology certainly can expand knowledge, but exploration without human involvement has no more spiritual content than a video game. No young boy or girl ever gazed at the night sky and dreamed of pushing the button that sends a computer and a camera into space. As Scott Carpenter said during his famous Friendship 7 countdown, Godspeed, John Glenn. And Godspeed, Barbara Morgan.