It was on December 21, 1968, that Apollo 8 was launched from Cape Kennedy, Florida, sending American astronauts Frank Borman, James Lovell Jr and William Anders on the world's first human mission to the Moon.
A few days later – on Christmas Eve in Houston on Christmas Day in Canberra – the three astronauts had just passed the Sea of Tranquility on the Moon and were approaching the sunrise when they sent a historic Christmas message to the people from the earth.
Read more: Curious Kids: Why can I sometimes see the moon during the day?
A few hours later, an Australian tracking station took over as main data and relayed the receiving location of the mission.
Located among the eucalyptus and kangaroo trees on the outskirts of Canberra, Honeysuckle Creek Tracking Station heard the crucial acquisition of the signal as the spacecraft emerged from behind the Moon in its final orbit, triggering its engine to return to Earth.
Honeysuckle Creek hosted and relayed astronaut Jim Lovell's first words to Mission Control on the way home:
Apollo 8: the mission that "saved 1968"
The Apollo 8 mission was only the second manned tour of the type of spacecraft that would carry the astronauts to the first lunar landing the following year.
Initially the mission was to test the lunar module on Earth's orbit security. But with this spacecraft not yet ready, NASA made the bold decision to launch a command and service module around the Moon as a precursor to a manned landing.
Also spurring the decision was the belief that the Russians were about to launch their own shot at the moon.
The Apollo 8 was the first manned launch of a huge Saturn V rocket, the first encounter with the Moon, and the first time human eyes saw the other side of the Moon.
The six-day mission was a spectacular success. The three astronauts completed ten orbits of the Moon and the spacecraft and ground support were thoroughly tested.
NASA was now one step closer to this "giant leap for humanity".
The astronauts also took the now iconic "Earthrise" photograph of Earth, behind a lunar landscape. This was a deep image, containing all of humanity, barring the three astronauts.
Read more: Earthrise, a photo that changed the world
Although the religious nature of Apollo 8's Bible reading has caused some controversy after the mission, it has been heard by hundreds of millions of people.
That the message was transmitted farther than the humans had ever been – the distance led to a one-second delay in all communications – made everything even more remarkable.
A member of the public famously wrote to NASA to credit the mission of having "saved 1968", a year plagued by wars and protests against Vietnam, civil rights and other issues.
Supporting Apollo below
The Apollo program, which allowed the first humans to come out of Earth's orbit, was overwhelmingly an American venture, but not exclusively.
Prior to space communication satellites, NASA relied on a chain of data-tracking and data-transmission stations around the world to communicate with satellites and astronauts in Earth orbit. To ensure adequate coverage, these included stations in distant places such as Madagascar, Nigeria and Woomera in southern Australia.
For additional missions to the solar system, NASA used three major stations: one near Canberra, Australia, which included Honeysuckle Creek, another in Madrid, Spain, and the third in Goldstone, California.
At least one of these three stations would have a plate that would face the spacecraft at any time, receiving its communications and passing them to Mission Control in Houston, Texas.
This was a global network of instantaneous data and voice communications at a time when even a single international phone call had to be booked weeks in advance and was extremely expensive.
For Apollo 8, Honeysuckle Creek received telemetry and voice communications when the spacecraft entered orbit behind the Moon when it emerged back into communication with the Earth, and when it began its re-entry into Earth's atmosphere on December 27.
Australian technicians were responsible for the vital task of aligning the spacecraft with the spacecraft and solving any problems that might arise with the equipment, an unlikely occurrence with the technology of the 1960s.
Support for other missions
While only Lovell would fly again, on the ill-fated Apollo 13 mission, all the equipment and procedures tested on Apollo 8 – the spacecraft, NASA technicians and the global network of tracking stations – would support the remaining Apollo flights.
Honeysuckle Creek was deactivated and dismantled in 1981, but its receiving dishes were not transferred to Tidbinbilla.
Read more: Part of Australia in 50 years of space exploration with NASA
Australia continues to play an important role in space exploration with scientists and technicians who still support NASA.
They are involved as part of the Deep Space Network, tracking spacecraft like the New Horizon mission to Pluto and several missions to Mars.
As for the two Voyager spacecraft, which traveled the furthest from any human object, they now only have Earth contact via Australia.
Even on Christmas Day, Tidbinbilla will be receiving messages from spacecraft around the Solar System.
So when you send out a Christmas message this year, spare a thought for those Moon messages 50 years ago, and the role that Australian scientists played in receiving them.
Tristan Moss received a Humanities Traveling Fellowship scholarship in support of this research. He completed his PhD in 2015 at the Australian National University, and published his first book Guarding the Periphery: the Australian Army in Papua New Guinea, 1951 – 75 in 2017 with Cambridge University Press. He previously worked on the Official Stories of Australian Operations in Afghanistan at the Australian War Memorial.