On October 29, the ground will shudder at the Kennedy Space Center in Cape Canaveral as the space shuttle Discovery lifts off, hurtling Glenn and six other younger and much less famous astronauts toward the heavens on a nine-day mission.

This dashing "young" old man of nearly 80 made history on February 20, 1962 when he became the first American to orbit the earth in the tiny cabin of his Mercury "Friendship 7" rocket, before plunging into the Atlantic.

His three orbits -- two more than the Soviet Union's Yuri Gagarin who shocked the world with his flight 10 months earlier -- put the United States back into the "space race" and calmed a nation in the throes of Cold War rocket envy.

Now, 36 years later, he stands to make history a second time as the oldest person ever in space and America is again watching him withadoring eyes.

Like many other publications, the celebrated magazine Life

adorned the cover of its October issue with Glenn's photo and the words: "The Last Hero."

He is everywhere. Glenn in space suit, Glenn dotted with sensors, Glenn in front of the shuttle, Glenn in training, Glenn speaking to children: print and television media are thriving on reverent coverage of this unique geriatric young man.

And for America's space program, which has been toiling in near anonymity since the end of the grandiose Apollo moon mission in 1972, John Glenn brings new life and adventure.

For precisely this reason, there have been detractors of Glenn's mission who regard the presence of the aging astronaut as glossy window-dressing on a cheap publicity stunt.

The National Aeronautics and Space Administration (NASA), sensitive to such criticism, has defended its decision, saying the flight is strictly a scientific one and that Glenn's experiences will help to better understand the aging process and how olderpeople will be affected by weightlessness and other space ills.

Glenn, a senator from Ohio who now splits his time between the Kennedy Space Center in Florida and the Johnson Space Center in Texas, has insisted on the seriousness of his role on Discovery, chiding the press for glorifying him.

"Too often you get into the human aspects of this and you don't get into the scientific stuff that gets into everybody's house all over this country," he said recently.

The crew will conduct 83 scientific experiments on board the Spacehab laboratory in Discovery's cargo hold. They will also deploy the Spartan space observatory that will study the sun's corona, in particular its eruptions on the star's surface.

Other than Glenn, the team is remarkable for its diversity. There is an astronaut from the European Space Agency, as well as one from Spain and Japan.

But America only has eyes for Glenn, its resurgent "old hero" who will make his last trip into space and return to Cape Canaveral on November 7 under anew halo of glory.