Messages from the moon

As tentative steps were taken on the surface of the moon, the intrepid Apollo crews positioned five retroreflectors pointing back to planet Earth.  Over time, these mirrors proved to be a critical element in determining our precise position, ultimately leading to advancements in the global positioning systems we take for granted today.

In 1974 the mountains of Namadgi National Park became the home of an ambitious scientific project in which pin-point lunar measurements operating within the realms of nanoseconds was established. Nestled high in the tranquillity of the Orroral Valley, looking down upon a NASA Tracking Station, an impressive domed building was built, capable of calculating a thousand millionth-part of a second.

It was precise, it was cutting edge.

For the next quarter of a century, the Orroral Geodetic Observatory proved to be an incredible scientific window gazing on our universe, one of only two such stations in the southern hemisphere. When the Observatory fired a laser pulse to the moon, it took 2.5 seconds to travel 385,000 kms, bouncing off a mirror and travelling back to Earth.  The observatory’s exceedingly accurate measurements improved our scientific understanding of the earth’s rotation, movement of tectonic plates and continental drift.

So accurate were the astrophysical measurements that four caesium atomic clocks were installed. The time set by these clocks contributed to the determination of Universal Time around our globe. One clock was designated as our national primary standard of time; its purpose was to keep Australian time accurate to 100 nanoseconds. It was the ultimate time keeper.  It was the benchmark by which time was set.

Decommissioned in 1998, the 18 tonne astronomical telescope was removed, atomic clocks reallocated, satellite dishes turned off. But the Observatory stood as time marched by and some twenty years later, life is being breathed back into the grand old majestic building.

Under the stewardship of Parks Field Officer Mark Rodden, we are reopening the precinct to the public as a way of gleaning an insight into the amazing cosmological role the Observatory once played.

We are reaching out to our community to hear the stories of those who fired the lunar laser, kept watch over the atomic clocks and who professionally contributed to this remarkable chapter of our universal history. Their stories will guide our development of a holistic interpretation strategy.

If you once worked at, or know someone connected with the magnificent Orroral Geodetic Observatory, please drop us a line We would love to hear from you.

Brett Mac

Brett McNamara - Regional Manager with ACT Parks & Conservation Service

Brett loves our national parks almost as much as the Gang-gang on his uniform. He is prone to using the word 'majestic' when referring to the bush capital. He loves talking. A lot. His favourite animal is the playful Platypus.

Article also appeared in The Chronicle