Simplify the following text for a Grade 9 native English-speaking person.
Original: In the early 1980s , NASA planned to launch a modular space station called Freedom as a counterpart to the Soviet Salyut and Mir space stations , while the Soviets were planning to construct Mir-2 in the 1990s as a replacement for Mir .
Simplified: In the early 1980s , NASA planned Space Station Freedom as a counterpart to the Soviet Salyut and Mir space stations .