We can get to Mars but we can't even turn off the aging process, what's the holdup?

The mind ages as its becomes acclimatised to a certain way of life, reconciled, defeated maybe, harmonised, in cahoots, in tandem. Thus the ageing process is a natural phenomena of living the esoteric emotional spiritual life. Whether charitable and giving, compassionate and fair, or parasitic and resentful, vengeful, hateful - the formation of the ageing face is an amalgam of these components composite of the character personality type of the personage. 

We're not spiritually ready for that.

Well, we haven't gotten people to Mars, so "can get" is an unproven assertion. That said, we probably will get people to Mars before we turn off the aging process. That's because turning off the aging process is a lot more difficult than going to Mars will be and because sending a crew to Mars risks a few lives, but messing with human DNA to turn off the aging process risks everybody's lives, seeing as how getting it wrong (like we people often do when doing something for the first time) has an enormous potential for completely wiping out the human race. I mean, imagine even trying to get there by experimenting on lab rats. Can you even begin to fathom the ecological disaster that would ensue if we succeeded in making rats unaging and with a potentially infinite lifespan and that somehow got out? We'd soon have a world so overrun by rats and that ecological disaster could easily result in the extinction of our species.