Nobody survived being in a lifeless void until Yuri Gagarin. On April 12, 1961, he became the first man in space, flew one orbit in 90 minutes and landed safely. Not willing to risk a national hero, Gagarin was never made prime crew again, although he did serve as backup. Still, he was the first.
The first man to walk in space. Had the Soviet Union's Lunar Program succeeded, he might have been the first cosmonaut on the moon. Yet just because the Soviets never left orbit doesn't mean he was done. He commanded Soyuz 19, the Soviet flight for the Apollo-Soyuz Test Project mission: the first joint mission between the US and USSR
The first woman in space. Of the six male Mercury astronauts to fly, they accumulated 36 orbits. Tereshkova alone flew 48 orbits on Vostok 6. The Soviets used this as propaganda as they portrayed the US as a male dominated misogynist society while they portrayed themselves as a gender equality society.
The only cosmonaut to be on the list for a tragedy for his outstanding display of selfless sacrifice. He knew the Soyuz 1 spacecraft had 203 documented faults and tha Brezhnev would not give the engineers more time to fix it. Knowing that his good friend Yuri Gagarin would fly it if he didn't, he stepped up to the spacecraft to protect his friend.
The first human to remain in space for a whole day. 25 hours instead of 24 so there would be no fluke. First to eat in space and the first to sleep in space. Vomiting a few times, he was also the first to get Space Adaptive Syndrone, which would evade American and Soviet doctors for the next few years.
These two have to share a spot as they are the first "partners in crime" in space. On August 11, 1962 Nikolayev launched on Vostok 3. The next day, Popovich launched on Vostok 4. They came within 4 miles of each other in space and made the first ship to ship communications. They both landed on August 15. Popovich landed prematurely due to miscommun
Who says the girls can't do what the guys can. In 1982, she becomes the second woman in space on her flight to Salyut 7 (A Soviet space station). In 1984, she returns to Salyut 7 making her the first woman to fly twice. But the highlight of the stay on the station is her becoming the first woman to walk in space. You go girl!
This two time Soyuz veteran becomes the first cosmonaut to fly aboard an American spacecraft (the space shuttle) on February 3, 1994. Three flights later (including twice on the space shuttle) he retiers after accumulating 803 days in space.