It hasn't been very long. In our history, there are a few landmarks to go off of, such as the Apollo mission, which was in 1969. If I remember correctly, space travel had already been achieved by even 1961 with the... what was it again? The Vostok program.

[Ah yes, her history lessons. She's very curious to discover how hers and Diana's timelines diverge so strongly.]

The field of space exploration has truly grown by leaps and bounds.