Why did the first astronauts go to the moon?

Why did astronauts go first to the Moon?

When President Kennedy announced plans for the Apollo program on May 25, 1961, the aim was to get men to the Moon and back, safely, before the decade was out. The target was the Moon not Mars, Venus or Jupiter and nobody seriously considered any other.

Distance was the key. The Moon is much closer to us than anything else in the solar system. On average, it is 384 400 km (238 900 miles) away. The closest that Venus comes is about 110 times that distance, and Mars is twice as far as Venus. Except for the Moon, those are our nearest neighbours.

Apollo took four days to reach the Moon. If the destination had been Mars, Neil Armstrong and his team would have taken at least 270 days. Another factor is that the Moon’s gravity is much weaker than that of Mars or Venus. Apollo would have needed to carry much more fuel not just for the longer journey but to generate the lift off force to free itself from gravitational pull before heading back. The escape velocity from the Moon is 2.4 km (about 1.5 miles) a second; from Mars 5.1 km (3.2 miles); and from Venus 10.3 km (6.4 miles) a second more than four times as fast.