Stanford's Quarter System

I’ve never heard of a quarter system being used before and I’m hoping someone may be able to help me understand it a little better. For the particular MS that I’m doing (AeroAstro) I am required to complete 45 quarter units. I seem to remember that AeroAstro had a 1 year MS, but can’t seem to find this explicitly stated anymore since their website has been “spruced up” (any confirmation for or against this would be much appreciated). If this is the case, does it mean that I will need to complete 11-12 quarter units per quarter thereby taking about 4 courses per quarter since most are 3 unit courses?

I seem to remember reading somewhere that quarter systems actually have 3 quarters of teaching, where the 4th quarter is dispersed as a holiday throughout the year. In that case would I need to complete about 5 courses per quarter?

There are 3 quarters in the academic year: autumn, winter, and spring. The summer quarter is optional. One year of credits is 45 units, so that’s an average of 15 units per quarter.

http://aa.stanford.edu/academics/graduate-programs/masters-program/how-apply

Here are the degree requirements that I found.

As @goldenbear2020 stated above, 45 units is the average academic year.

Having looked at the LinkedIn profiles of few MS students in AeroAstro, it seems like many completed their MS over what I assume to be two years (e.g. 2007-2009, or 2013-2015), implying that they must have taken less than 15 units per quarter on average. Is the workload different at the MS level (i.e. 15 units per quarter at the graduate level is far more difficult than 15 units at the undergrad level)? I was hoping to complete my MS in a year due to the high cost of tuition, but is this an unrealistic plan?

MS students at Stanford tend to take 8-10 units, so they’re probably taking as many as 5 quarters to finish, e.g. from Autumn 2015 to Winter 2017.