Let's see how much of the TNA television history I can remember off the top of my head.
June 2002 - June 2004: Weekly PPV main show, Xplosion secondary show on WGN
June 2004 - June 2005: Impact airs on Fox Sports Net, horrible time slot of Friday afternoon around 3pm, monthly PPV events
June 2005 - Fall 2005: Impact is webcast exclusively, monthly PPV
Fall 2005 - early 2006: Impact is on Spike and airs Saturday nights with replays the following Thursday, late night slots
Early 2006 - January 2010: Impact airs prime time on Spike on Thursday
January 2010 - May-ish 2010: Impact airs live on Monday head-to-head with Raw because Bischoff/Hogan have no new ideas, replays on Thursday
After that, I'm pretty sure Impact aired on Wednesday to avoid SmackDown (which went from Friday back to Thursday back to Friday), Spike cancelled the show after massively declining ratings thanks to Dixie being even worse hands-on than she was hands-off, Jarrett coming back and trying to rebrand it as Global Force and ohnoivegonecrosseyed