CAPECANAVERAL, Fla. (AP) _ John Glenn vividly remembers everything about the day,40 years ago Wednesday, when he became the first American to orbit the Earth.

It'sno wonder.

``Iguess it's been a rare day that somebody hasn't brought up something aboutthat,'' said Glenn, who at age 80 is the first astronaut to reach the 40-yearmilestone. (All four of his space predecessors have died.)

Thequestion he is asked most frequently about his flight aboard Friendship 7 onFeb. 20, 1962: Were you scared?

Afterall, he was only the third American and the fifth person in the world to rocketinto space, and the first to ride the Mercury Atlas into orbit.

No,he was not afraid, but he was apprehensive.

Statisticalstudies at the time gave him a 90 percent chance of returning alive, Glennsaid.

Atthe time, psychiatrists feared weightlessness might prove so euphoric he wouldnot want to return to Earth; they called it the breakaway phenomenon. But Glennsaid he thought it was nonsense.

``Ican laugh about them now, but they were serious then, I'll tell you,'' he saidin an interview last week.

Duringthe five-hour, three-orbit flight, Glenn had to overcome problems with the capsule'sautomatic control system and contend with grave concerns about the spacecraft'sheat shield.

Theretired senator, who made a comeback as the world's oldest spaceman in 1998aboard space shuttle Discovery, said he is disappointed NASA has yet to sign upanother senior citizen to help produce more data on the effects of space onolder astronauts.

Glennstill flies his own plane and takes an active role in The John Glenn Instituteat Ohio State University, created to promote public service and policy.

Hewill mark his 40th space anniversary with a sold-out lecture at the SmithsonianInstitution's National Air and Space Museum and a call to the crew of theinternational space station. On Sunday, he will be reunited at Cape Canaveralwith the three other surviving Mercury astronauts.

Glennintends to be around for his 50th anniversary, maybe even his 60th. ``Gettingold is two things, attitude and exercise, that keep you going,'' he said.