Here is the audio of the fire. I really got me when I first heard it especially how astronauts are trained to be calm under pressure.
For me it’s two that I can’t choose between.
One is the Christmas reading of Genesis. So beautiful.
The other is the “one small step” quote.
In 1969 I watched the TV with my grandparents. I was so keyed up I could not make sense out of what was on the screen. Armstrong was coming down the ladder of the LEM and I couldn’t see it! I kept saying “Where is it?” I never took my eyes from the screen but didn’t really “see” it until a repeat showing.
It’s not a spoken line, but I always liked “We came in peace for all mankind.” from the Lunar plaque.
Going to voice recorder.
“You bet your sweet ass I am.”
I don’t know if I’m the only one that doesn’t have a clue what you’re talking about, but no I can’t guess what a National Guardsman in Texas in 2003 did for a job. Who found what bodies and what serial killer? What are you not saying out of respect and why mention it if you’re not going to be specific? 
I am guessing he was assigned to search for debris and remains from the Columbia disaster in February, 2003. The Columbia broke up mainly over Texas and Louisiana. Seven of the bodies (or remains of bodies) would be the seven astronauts. I guess he probably found some human remains of one of the astronauts.
I have no clue about the other two, however, the supposed serial murder victims.
I recall when the first space shuttle was returning to earth we were told that we here in Southern California would hear a double sonic boom. Sure enouigh, I was still in bed when BOOM,BOOM! I was delighted as if I had somehow been a witness to the shuttle’s return.
Oddly enough, despite the many shuttles returning to Edwards, I never heard another double boom.
Heeeeeey! I didn’t know that pic had been taken in my first Christmas! Gosh. I feel like I got a Christmas gift, like the first time I read a book talking about travel to other worlds…
Apollo 12. Pete Conrad on stepping from the lander to the surface of the moon.
“Man, that may have been a small one for Neil, but that’s a long one for me!”
From the wikipedia website on T.J. O’Malley (found while looking for the quote, I came across a youtube clip and couldn’t work out what the first voice was saying!)
Ground control to John Glenn as he is about to launch:
“May the wee ones be with you, Thomas”, a good luck reference to the leprechauns of Irish mythology. O’Malley made the Sign of the Cross, and said, “Good Lord ride all the way”, just before backup astronaut Scott Carpenter, also seated in the blockhouse, made his iconic remark, “Godspeed, John Glenn!”
And I don’t know if there is any audio recording of it but, “Poyekhali!”, Russian for “Let’s go!” or “We’re off!” shouted by Gagarin as he lifted off the pad.
I always thought that it should be a tradition for spacefarers of all nations to say that at the start of a mission. 
I watched ‘The Right Stuff’ again recently, we’ve definitely passed through something of a heroic age with the first manned flights, I hope to live long enough to see it again.
I have no idea if it’s a real quote or something they made up for the movie, but when Jim Lovell’s mom says, “If they could get a washing machine to fly, my Jimmy could land it,” it always gets me. That is parental pride.
The one that made me emotional wasn’t a line - it was the silence on 2/1/2003 at 9:16 AM, when there should have been communication between NASA and Space Shuttle Columbia touching down at the Cape. (IIRC, they left the giant “countdown clock”, which was counting down to the scheduled landing time, on, as they still weren’t quite sure what had happened.)
Uttered by another proud mom, Ron Howard’s mother.
Shepard was recorded as saying while on the pad in Freedom 7, “Don’t fuck this up, Shepard.”* Later this was misquoted and became known as Shepard’s Prayer, “Dear Lord, please don’t let me fuck up.”
*Story goes, when the Cap Com asked for a repeat, he replied “I said ‘Everything is A-Okay’”. This reminds me of Sergeant Colon’s translation of the City Watch’s motto, “Fabricati Diem, Pvnc” as “To Serve and to Protect”
Reading the Wiki entry on the Apollo 1 fire this jumped out at me (regarding the location of the astrounaughts bodies after the fire):
Bold - mine.
Just…damn…staying in place to keep comms open while you rely on your crew-mates to get the hatch open. Takes serious guts to do that.
Which Mercury astronaut said, “Let’s light this candle.”?
Alan Shepard.
Thanks.