Trapped by Time is an awesome episode. I remember the first time I saw it, when Sandoval realizes he's been betrayed it actually came as a twist to me when he then rolled up his sleeve and his skrill crawled down. Really cool moment.
As for the astronaut's predictions, all I'll say is that some of it does come true. By the end of the series you'll realize why humanity had to revert to their own technology for space travel and why the astronaut said "skrills are illegal."
Also, you have to really pay attention, but this episode kind of reveale when the series takes place. Heather North's uncle (or whatever he is) says he worked for NASA until the arrival of the Taelons forced NASA to shut down "in 05." Taken literally this would mean season 1 is set in 2008, three years after the Taelons arrived, according to the opening monologue. However, season 2 is in an election year, so that will have to be 2008. This is easily solved, the Taelons arrived in 2004 and for various administrative and beuracratic reasons NASA didn't officially shut down until 2005.
So, if we then assume the Taelons arrived in 2004, season 1 would have to be 2007. This would allow season 2 to be an election year and would mean the series itself lasts from 2007 to 2011. Or possibly 2012, since a late season 5 episode is set on New Year's.