Robots are most definitly affected by radiation [link] for example the 2003 mars rover only had 128MB ram memory whilst a run of the mill 2006 playstation 3 has 2X256MB ram. Sure but tele-operation can be achieved much sooner. Also for Insurance reasons it's from a legal view easier to have a human in control so you have someone to blame if something goes wrong. because we're human it's a easy answer but people never had any problem to find someone to trek over antartica or climb a really tall mountain that should be considered a punishment if you think abouth it, yet people do this things and are proud of it. That is naive whisfull thinking if that would be true, the rich and powerfull would take care of the climate and put inmense research in longevity. We don't each and everyone of us tries to get their little slice of happyness that in itself isn't bad but multiply that with 6 billion and it quickly becomes a disaster. And more I hope. the real important development is space flight at the moment is the development of cheaper rockets (like space x,) and more exotic thinks like the skylon plane. If things were cheaper we could do more.