Exactly and that's not mentioning the benifit of being able to easily recover a failed prototype or even just analysis of a failed prototype.

Imagine trying to diagnose a problem that comes up 10 months into the program after the probe is no longer in a direct visual path or while communications via microwaves start taking 10-20 seconds from point to point.

There are too many questions to be answered before we can just say "you know while we're at it lets just risk the lives of 10-20 people, who cares right?"

On the other hand, 10-20 people in a bus out of control on a mountainside can get in the news, even if it ends in tragedy. But we don't color our whole view of auto travel because of it. We don't make policy or even many business decisions because of it.

Space travel can be dangerous. We will likely lose some crews. Rescue will always be too far away to matter. But I think folks will do it anyway.

Of course they will.

  Say to me, "There's too much danger."
  Say we could be lost,
  And I reply, "I'm no stranger
  To danger. That's the cost."

https://www.youtube.com/watch?v=Oet1j9EA2fs&index=10&list=PL...

(Incidentally, this lovely song is a good answer to a lot of comments on this story.)

I don't understand why the human cost of space travel is always weighted so heavily. All exploration costs lives.

How many died conquering America? Exploring the poles? The Everest?

To this day people die in the Everest. It's their choice to risk their lives in such a way. Yet I don't hear people saying "don't go there".

Space is riskier, but also has more rewards.

Yeah lots of volunteers could be found for a one-way to Mars.