When I was a little kid I was fascinated with space travel. I would pore over books about the original Apollo missions to the moon, and would rapturously read anything that could take me close to the adventure, the planning, or the ingenuity of the whole thing. I was only one year old when Neil Armstrong and Buzz Aldrin first made that most exhilarating climb down the six or seven steps on to the moon’s surface. As a young boy I dreamt of doing the same—not yet discouraged by my lack of ability in maths, nor my claustrophobic terror of small, enclosed spaces.

Although harsh reality had long replaced those dreams by the time I was 17, my Dad, no doubt remembering his boy’s early romance with all things NASA took me to hear a speech by Jim Irwin, an astronaut who spent three days on the moon in 1971. Irwin’s mission famously involved the use of the moon buggy for the first time.

During the address, given in a bowling club in a country town in New South Wales, which must have seemed galaxies away from space travel glory for Irwin, he told a story I never forgot. He described a profound moment standing on the moon, and looking back at earth. Closing one eye, Irwin held up his thumb and covered the entire earth—every mountain, every city, every person, every valley, every ocean. All under his thumb. Irwin said it made him feel terrifyingly small.

He went on to suggest that most of the astronauts involved in those early days of space walks and moon visits, had either become Christians, or gone mad. The experience was so overwhelming. Irwin himself had a long held faith that he said was only deepened and enriched by the adventure.

This week, on the 45th anniversary of the first landing on the moon, I read that Buzz Aldrin took communion before making that short, bold walk into history. After the lunar landing, Aldrin radioed back to earth, “This is the LM pilot. I’d like to take this opportunity to ask every person listening in, whoever and wherever they may be, to pause for a moment and contemplate the events of the past few hours and to give thanks in his or her own way.”

Then in the silence surrounding him, Aldrin quietly read from John’s gospel, ‘I am the vine, you are the branches. Whosoever abides in me will bring forth much fruit. Apart from me you can do nothing,’ before taking in bread and wine that he’d brought specially for the occasion.

In this moment of astonishing human achievement, Aldrin clearly felt his own helplessness and dependence on the creator—the one who the Bible claims “stretches out the heavens like a canopy … who brings out the starry host one by one, and calls them each by name.”