Hi There!!
Your best answer choice is:
-Sputnik 1 1957.
-Sputnik 2 1957.
-Explorer 6 1959.
-Vostok I 1961.
Well, I really don't know these are the correct orders....
But, I hope this helps you!
:)
Answer:
first humans on the moon, first lander on Mars, first space shuttle flight
Explanation:
I checked and it's correct. promise
