1, Relative clause: “which is formed from two Greek words”

=> The word astronaut, formed from two Greek words, means “star sailor”.

2, Relative clause: “which reach an altitude of 100 km or more”

=> Only flights reaching an altitude of 100 km or more are considered space flights.

3, Relative clauses: “who are chosen to become NASA astronauts” and “”which lasts twenty months”

=> People chosen to become NASA astronauts have to complete a difficult training programme lasting twenty months.

4, Relative clauses: “who spend long periods in space” and “which have been designed to keep them strong”

=> Astronauts spending long periods in space do exercises designed to keep them strong.

5, Relative clause: “which intend to escape from Earth’s gravity”

=> Spacecraft intending to escape from Earth’s gravity need to reach a speed of about 40,000 km/h.

6, Relative clauses: “who watched the Apollo 13 mission on TV” and “who listened on the radio”.

=> People watching the Apollo 13 mission on TV or listening on the radio were very relieved when the astronauts returned safely.

7, Relative clause: “which was awarded by NASA”.

=> James Lovell received the Exceptional Service Medal, awarded by NASA.

8, Relative clauses: “which was made in 1995 and starred Tom Hanks” and “which included nine Oscars”

=> The film Apollo 13, made in 1995 and starred Tom Hanks, was nominated for many awards, included nine Oscars.