six million dollar man - What plot points/cultural significance would making Steve Austin a civilian member of NASA have served?

When The Six Million Dollar Man premiered (1973) in the United States had just ended its involvement in the Vietnam War. The US military was not held in high regards in many circles and having Austin be a veteran might have been seen as "problematic." The pilot seems to have done away with this by having Austin be a civilian test pilot who was the only civilian ever sent to the Moon.

After two additional television films (during which Steve Austin was returned to his former military rank) the series was picked up by ABC as a weekly series in 1974. The improbability of Austin having been a civilian astronaut was probably brought the attention of the producers who simply changed the back story during the second pilot film.

In this respect, the television series began to match Martin Caidin's novels. The show later expanded upon Austin's background adding a family and then later love interest, Jamie Sommers, who herself became The Bionic Woman.