There were several high level NASA people who were happy when Apollo 17 ended. The moon missions were super risky and they were certain that sooner or later, they'd lose a crew. After the grilling they took on Apollo 1, they started to get gun shy. Of course, simply going to and from LEO proved dangerous enough, killing two Shuttle crews (and two Soviet crews as well).

How can we possibly continue to send humans into space when our society seems to becoming increasingly risk adverse? Honestly, I don't know. We can study and design the missions for decades to improve safety somewhat, but it's unlikely that space travel will ever be "safe."

According to a report I've read, some 4% of all the people who have flown into space have died on a mission. Despite these known risks, there's no shortage of people willing to fly into space. If we're going to have people risk their lives on spaceflight, can't we do it for something meaningful? Going once again "where everyone has gone before" (LEO) hardly seems meaningful to me.