The Fated Sky - Mary Robinette Kowal
I rushed to buy this book the minute after finishing its prequel - The Calculating Stars. Mary Robinette Kowal has created an wonderful alternate history - dealing with the practical problems of going to Mars. Not just technical - but sociological.
It's not as as recklessly disaster ridden as Andy Weir's The Martian, but it has its fair share of heart-stopping moments. I'd gladly read a couple more books set in this universe.
It gets a little repetitive - with our fearless Astronette waxing lyrical about her love of baking, and a few too many paragraphs are dense technobabble and encrypted text. But I'd be churlish to call this anything other than great. It left me with a big grin on my face and a heart full of hope.