In late 1968 NASA asked for the Parkes radio telescope to be used in the Apollo 11 mission. The giant telescope was the prime receiving station for the first Apollo 11 signals from the Moon. Two NASA stations also received the signal simultaneously. They were the Honeysuckle Creek tracking station in the mountains outside Canberra, and NASA's Goldstone station in California.

The signals were sent to Sydney via specially installed microwave links. From there the TV signal was split. One signal went to the ABC studios at Gore Hill for distribution to Australian television networks. The other went to Houston for inclusion in the international telecast. Because the international broadcast signal had to travel halfway around the world from Sydney to Houston, Australian audiences witnessed the moonwalk, and Neil Armstrong's historic first step, some 300 milliseconds before the rest of the world.

The Parkes telescope also played an essential role in the successful recovery of the Apollo 13 astronauts in April 1970. On April 14, fifty-five hours and fifty-five minutes after departure, the spacecraft suffered an explosion in an oxygen tank, crippling the Service Module which carried the main propulsion system, oxygen, water and other consumables. With rapidly decreasing supplies, the lives of the three astronauts were under serious threat.

As the moon was too far north to be observed from Parkes, the telescope was not scheduled to track Apollo 13. After the accident it was quickly realised that the only way the astronauts would get back alive would be for them to occupy the Lander Module and use its facilities to orbit around the far-side of the moon and then head straight back to earth. The then Director of the Parkes Observatory, Dr John Bolton, realised that Parkes would be needed to track the failing spacecraft on its return journey.

Bolton and his staff immediately began to prepare the telescope for tracking. Whilst the astonomer's equipment was carried down a ladder on one of the telescope feed legs, NASA equipment was taken up to the focus in a lift. The telescope was ready for tracking within 10 hours, a task that usually took one week.

As Apollo 13 travelled towards the earth, tracking data showed that the spacecraft was slightly off course. Without a small correction to its orbit it would not be able to enter the Earth's atmosphere. The spacecraft would be accelerated away from the Earth towards a cold death. With very little power left, the crew applied a short engine burn and this successfully put the craft back onto a perfect path for re-entry.

Five days after the explosion, while millions around the world watched with bated breath, the Apollo 13 crew returned to Earth, freezing cold and dehydrated, splashing down safely in the Pacific ocean, on April 18 1970 (Australian time).

For more information about the role that Parkes played in the Moon landing you can check out "On Eagle's Wings" by John Sarkissian at www.parkes.atnf.csiro.au/apollo11/