Which identifies a fact given in the speech?

If this capsule history of our progress teaches us anything, it is that man, in his quest for knowledge and progress, is determined and cannot be deterred.

The exploration of space will go ahead, whether we join in it or not, and it is one of the great adventures of all time, and no nation which expects to be the leader of other nations can expect to stay behind in the race for space.

Within these last 19 months at least 45 satellites have circled the earth.

Its conquest deserves the best of all mankind, and its opportunity for peaceful cooperation may never come again.