First artificial satellite.
Study the effects of space on a biological creature.
A chimpanzee named ham went into to space to investigate.
Yuri gagrin was the first man in space.
The first american, to go into space.
The Gemini missions, helped us learn about humans walking in space, with a space suit.
The first satellite, to do a fly by of mars.
It was the first successful moon landing.
The first satellite, to take pictures of Jupiter.
It was the first spacecraft, to visit Mercury.
It took advantage of a rare planetary alignment.
Study Pluto system. And study objects in the kaiper belt.