To arrange the key events in the exploration of space in chronological order, the correct sequence is:
- First humans in space (Yuri Gagarin in 1961)
- First humans on the moon (Apollo 11 in 1969)
- First space shuttle flights (first shuttle launch in 1981)
- Launching of the International Space Station (1998 onwards)
- Last humans on the moon (Apollo 17 in 1972)
- First lander on Mars (Viking 1 in 1976)
- Hubble Space Telescope launch (1990)
- First humans on Mars (not yet accomplished as of October 2023)
The most appropriate order you might be looking for based on the options provided is:
- First humans in space, first humans on the moon, first space shuttle flight.
This sequence starts with the earliest event and progresses to later significant milestones.