A lot of the dialog is blatant info-dump. For example:
This needs only an "As you know . . . " in it to be egregious. I think that's called a 'Tom Swift.' It jumps out at the reader as something the listener(s) in the dialog already know(s)."Thank God for enthusiastic graduate students," Professor Schmidt said. "They arrived two weeks ago, began drilling last Friday. We'll have some good deep core samples. Right, Augie?"
The reader needs to know this stuff, but there are better ways of conveying the information. Probably easiest in this particular instance would just be to put it in narrative form, and it wouldn't be a bit bothersome. Another good trick, where applicable, is to have such conversations at an earlier time in the plot-line, where the characters don't know such things yet.
The rest of the story isn't bad; characters could use a little smoothing out; the plot is okay, and the ending is a little unnerving: they may be back any day now to bomb us again (although for what reason is a mystery). The science part of it seemed plausible to me, but I could be mislead or uninformed; Bill will no doubt be along shortly to comment on that.
The basic stuff is here for a better story, Gino -- you just need to work on that clunky dialog, more than anything else.