The 20th marked 36th anniversary of Neil Armstrong and Buzz Aldrin setting foot on the lunar surface, how will Amercia mark the 40th in four years time ?
In 61 Shepard in a Mercury capsule , and then Gus Grissom in NASA’s second space launch, both fly sub-orbital and 1962 NASA launched Glenn into space aboard the Friendship 7 spacecraft.

the 50th anniversary for these are coming soon - 2011