Well, they have one shot at this so it has to be 100% perfectly correct because once it's gone it's gone. I, for one, would much rather have them work out all

Well, they have one shot at this so it has to be 100% perfectly correct because once it's gone it's gone. I, for one, would much rather have them work out all the kinks on the ground than shoot it up into space before they're absolutely sure and then find out the thing is lost because they set a cotter pin at 28° instead of the required 32° so the heat shield didn't deploy. Though I'm sure if they successfully get the thing where it needs to be and there is a problem they can just send up some robots to fix the thing in another 20 years or so...