| A | B |
|---|
| refracting telescopes | have convex lenses |
| reflecting telescopes | uses concave mirrors |
| Alan Shepard | first US citizen in space |
| John Glenn | first US citizen to orbit Earth |
| Project Apollo | final step in US program to reach the Moon |
| Apollo 11 | landed on Moon's surface |
| Armstrong and Aldrin | walked on Moon |
| Space Shuttle | reusable spacecraft |
| observatories | optical telescopes are located in these |
| rockets | special motors that don't require air |
| satellite | revolves around another object in an orbit |
| orbit | curved path |
| Project Mercury | first step in program to reach the Moon |
| space station | permanent place in space |
