Bill Wilcox stares down at his watch, marking a moment half a century in the making.

At that exact moment, at 2.20pm on July 21, 1969, just as man first walked on the moon, Bill and his comrades were hit by a mine.

And although it is sunny and quiet, Bill remembers something very different.

He remembers an explosion of dust and shrapnel, blood and the cries of injured men.

He remembers a day that changed his life, and the world, forever.

Bill was injured when he was serving in Vietnam as a field engineer.

His job was a terrifying one - checking villages, tunnels and bridges for mines, as well as disposing of unexploded mines.

At 20-years-old, the young soldier who hailed from Oberon in NSW, was picking his way with his fellow engineers to help members of the Third Platoon, A Company, 6th Battalion, the Royal Australian Regiment, who had been hit by a hidden mine.

It was here Bill helped save the life of Frank Hunt, or Frankie, whose name was used in Redgum's famous song I Was Only 19.

The line "Frankie kicked a mine the day that mankind kicked the moon," actually refers to Lieutenant Peter Hines, the commander of 3 Platoon, "A" Company, 6^th Battalion.

Lt Hines's widow says he was standing up to tell his men about the moon landing when he stood on a landmine. He used his dying breaths to give instructions to his men to try and keep them safe. A memorial service at Wangi Wangi was held in his honour on Saturday.

Also killed was Bill's good friend, Private Johnny Needs, when the men were thrown into the air by the explosion.

Bill landed 20 feet away, with 60 horrific wounds to his side, and his hand and knee smashed.

He was winched out by helicopter, but only just survived.

When he finally gained consciousness after surgery, the first thing he heard was 'one small step for man, one giant leap for mankind' as the moon landing was replayed on the television.

For 50 years Bill has carried pieces of shrapnel throughout his body.

Bill had planned to return to the spot he was injured on the 50th anniversary, and says kneeling there at the exact moment was 'pretty hard'.

Bill was accompanied by his great niece Tara and his great-niece Amelia.

"It was a beautiful warm day, and we were walking down the track, and I stopped and said 'this is the spot'," he said.

"It had changed a little bit but I knew it was the place."

Bill said 10 other members from a range of military units also accompanied him.

"I met a guy while I was there who was right behind by mate and cousin Harold Hurst when he was killed in April 1970," he said.

Bill said he also showed his family members around his base at Nui Dat and Long Tan.

And for Bill, who is the president of the Oberon RSL Sub Branch and Blue Mountains RSL, despite decades of honouring the heroes of war and supporting war widows, this was one of the most difficult moments.

"It was pretty tough. It was emotional. To be there at the time and to meet up with these guys, it was unreal," he said.

And that moment, as he shed a few tears and looked at the shrapnel-peppered watch he wore 50 years ago, it was the end of a chapter.

"It is the last time I will go there," he said. "But I'm so glad I was there."