As it is for the STEM program, your second sugestion could do it. It could be nice to introduce them to the Engineering Design Process as it goes with your sugestion. Start with a problem "Jeb want to go to space, How can he get there?" They will probably respond by you need a rocket. Build the simpliest rocket you can "Cabin, LFO tank, engine" Test it Analyze the result "Jeb got to 3km up then fall to is death" and ask them "was there someting missing from our rocket?" Add parachute and more tanks retest, reanalyze failure ... until you get to orbit. hope this can help.