The author has failed to say what we would have achieved by sending more people into risky space missions. For example, if our next goal is to get to Mars, we

The author has failed to say what we would have achieved by sending more people into risky space missions. For example, if our next goal is to get to Mars, we learn a lot about how to get the risks down by sending unmanned craft there. The excited group of engineers when MSL touched down last year is testament to the fact that this landing is still very hard. (And the difficulty is not entirely due to not having a pilot in the craft.)