As of today the word count on Book Two of Series is 70,866.
I expect it will top out again at just over 100,000 words. That is still a couple weeks at present pace.
A lot of this story takes place on a moon with low gravity. Lots of the main characters hate low gravity. I know I would if you had to suffer it day in and day out knowing your body was getting weaker and weaker...
It's challenging to write scenes that take place in weightlessness. Done well those scenes can be awesome. Enders Game comes to mind.
--I am also starting to think about the cover for book two.