NASA had Apollo-era plans to send humans to Mars and Venus

In an alternate universe — one where Americans had a LOT more enthusiasm for spending money on massive space projects than we've ever actually demonstrated — the 1970s and 1980s might have been the era of manned missions to Mars and Venus. Amy Shira Teitel writes about how this could have been possible, using only the now-antiquated technology that got us to the Moon and back.