Question: When did exploration to the inner solar system begin?
Answer: 1959
Disambiguated annotations:
qaPairs: question: When did exploration to the inner solar system technically begin with the launch of the first lunar flyby satellite?
answer: 2 January 1959
question: When did exploration to the inner solar system technically begin with the launch of Pioneer 5 for interplanetary space investigations?
answer: 11 March 1960
question: When did exploration to the inner solar system technically begin with the launch of Mariner 2, which resulted in the first successful flyby of Venus?
answer: 27 August 1962