But first, I am curious as to the "challenges" these celebrities will face. You know, dawning a Billy Jack hat does not make you Billy Jack - it just attracts the attention of everyone in the vicinity who is able to kick your arse! So it stands to reason that putting on the uniform of a Serviceman does not make you such - it just makes you a fake, phony, someone pretending to be someone else...oh, wait - that's the definition of "Hollywood" LOL
Now, back to the "challenges", what are they? Running through a simulated combat course with absolutely zero chance of breaking a nail? Perhaps the challenge is carrying a rifle with a gung-ho expression like you are intent upon using it in defense of your Country that you are prepared to die for? Possibly it is trying to make an enticing television program without offending actual combat veterans and active servicemen?
Picabo Street proclaims the experience is, "I thought nothing could compare to winning an Olympic Gold Medal...but this? This is epic!" Epic Fail, maybe. The fact that the producers could even conceive of this notion pisses me the McF off! That "stars" are so desperate for money (or for a boost of ego) that they would dawn the apparel of better men & women than they - REAL MEN & REAL WOMEN - to earn their imaginary stripes is a sad testimony of just how far out of touch Hollywood is with mainstream America.
Zeroes portraying Heroes is a fact of fiction. I personally knew some Heroes - but they are all asleep beneath Gardens of Stone. Does being a Marine in and of itself make me a Hero? F NO! It makes me (1) a survivor and (2) a brother to every other Marine. The word "hero" is used way too often. My heroes are all dead and know something that I as yet do not...peace, sweet and blessed peace.
I now rise in salute of the stars. Of course, it is the one-finger salute to reflect the true depths of my disdain for their vanity. I earned my title. I earned my stripes. Acting on television doesn't make you anything beyond a paid puppet...and I sure wish I could shove my hand up their azz and work their mouths like one

Folks, the actual real challenges of a serviceman is trying to combat home sickness. Worrying over what their significant other is doing "right now". Wondering if they will ever see home again. Wishing it was not so hot, so sandy, and that they could figure out somehow someway to keep their canteens cool. Hoping that they live long enough to earn the title short-timer. Wishing there was someway to detect & remote detonate IEDs before setting them off. Dreading Firewatch. Praying that those on that duty remain awake so they can finally get some sleep...
...those are some of the challenges beyond just trying to complete the Mission and stay alive while doing so - sometimes an impossible combination. Until one of those stars face those same challenges, F em all!