John Glenn, the first man in orbit

Overview
There's a probability that John Glenn, instead of Yuri Gagarin, would become the first human in the Earth orbit if the U.S. human spaceflight program starts earlier. What if that happens?

Timeline
1953: Soviet dictator Joseph Stalin did not die as in OTL. Point of divergence.

1954: Soviet rocket scientist Sergei Korolev defected to America with his family, with the help of CIA.

1955: Stalin dies.

1956: USA launched the first satellite Orbiter I is launched into orbit under the Project Orbiter program, shocking the whole world.

1957: The Soviets launched their own first satellite Sputnik 1, but the design is based on the more sophiscated "Object D" design. However, the USSR sent a dog into orbit later that year.

1958: NASA is formed with help from Wernher von Braun and Sergei Korolev. Its first interplanetary spacecraft Pioneer 1 is a huge success while its subsequent Pioneer 2 took back first images of the lunar far side.

1959: At this time U.S. launched the first hominid monkey into space.

October 1960: NASA sent the first man in space.

1961: On March, NASA astronaut John Glenn became the first man in orbit. Later on USSR launched Yuri Gagarin, their first man in space on a suborbital flight of Tikhonravov's rocket. Von Braun and Korolev began persuading the NASA to set sights on the Moon.

1965: The U.S. sent the first space station into operational mode. The station is based on the Mercury spacecraft design.

1967: Korolev dies as in OTL.

1968: U.S. made the world's first manned circumlunar mission.

1969: NASA astronaut Neil Armstrong is the first to step foot on the Moon. Contrary to OTL, the manned lunar landing mission profile is that of "Direct Ascent".

1970: Owing to huge American lead in the Space Race, the Soviets are demoralized and decides to give up.

1991: The demise of most the Communist World. Cuba and Vietnam is not spared in this TL.

2006: North Korea tested its first nukes.

2017: The 2nd Korean war began when North Korea attacked its southern counterpart with a surprise.