Chief of the CSIRO Radiophysics Division, Dr Edward 'Taffy' Bowen (right), with Dr John Shimmins, deputy director of Parkes Observatory, in the control room watching the moonwalk (21 July 1969).
Parkes and Apollo 11: receiving the moon walk
In July 1969, the Parkes Observatory claimed a place in history, when they received television transmissions of man's first steps on the moon.
1 February 2006 | Updated 14 October 2011
In 1968, the Director of the Parkes Observatory, John Bolton, insisted on a one-line contract with NASA: 'The [CSIRO] Radiophysics Division would agree to support the Apollo 11 mission.'
At 12.56 pm on Monday 21 July 1969 Australian Eastern Standard Time (AEST), one giant leap for mankind was taken. CSIRO’s Parkes radio telescope received television signals that allowed six hundred million people, one fifth of humanity at the time, to watch Neil Armstrong's first steps on the Moon.
The Moon walk
CSIRO¹s Parkes radio telescope received television signals that allowed six hundred million people to watch the Apollo 11 moon walk live.
A few hours earlier, at 6.17 am (AEST) on 21 July 1969, astronauts Neil Armstrong and Edwin (Buzz) Aldrin landed their Lunar Module, Eagle, on the Moon at the Sea of Tranquillity. It was still some seven hours before the Moon would have risen high enough to be seen from Parkes.
The schedule required the astronauts to rest before attempting the 'Moon walk' or extra vehicular activity (EVA), by which time the Moon would have been high overhead at Parkes. However, Armstrong departed from the original plan, opting for an immediate EVA instead.
To the astronomers at Parkes, it looked as though the EVA would be all over before the Moon rose over Parkes' horizon. However, it took the astronauts a long time for the astronauts to don their spacesuits and depressurise the lunar module cabin, so that when they left the module the Moon was just rising over Parkes.
When it seemed that Parkes would get the signals after all, trouble suddenly loomed.
While fully tipped over waiting for the Moon to rise, the telescope was struck by a series of severe, 110 km per hour gusts of wind, which made the control room shudder. The telescope was slammed back against its zenith axis gears, a dangerous situation that threatened the integrity of the telescope structure.
Fortunately the winds abated and Buzz Aldrin activated the TV camera just as the Moon rose into the telescope's field of view. The Parkes radio telescope began tracking.
Using a less sensitive 'off-axis' detector, Parkes was able to receive the TV pictures just as the lunar module's TV camera was switched on. Less than nine minutes later the Moon had risen into the field of view of the Parkes telescope's main detector.
As Parkes was the largest telescope to receive television signals from the Moon, it captured more signal and produced better pictures than the receiver at Honeysuckle Creek near Canberra, which received some of the first ten minutes of the EVA. Therefore, Houston switched to Parkes and remained with those pictures for the rest of the 2½-hour broadcast.
The weather remained bad at Parkes, with the telescope operating well outside safety limits for the entire duration of the EVA.
Australian audiences witnessed the moon walk, and Armstrong's historic first step, 0.3 seconds before the rest of the world.
The signals received by Parkes were sent to Sydney via specially installed microwave links. From there the TV signal was split. One signal went to the Australian Broadcasting Commission (ABC) studios at Gore Hill for distribution to Australian television networks. The other went to Houston for inclusion in the international telecast.
The international broadcast signal had to travel halfway around the world from Sydney to Houston via the INTELSAT geostationary communications satellite over the Pacific Ocean. This added a 300 millisecond delay to the signal.
Australian audiences therefore witnessed the EVA, and Armstrong's historic first step, 0.3 seconds before the rest of the world.
CSIRO staff involved
Unlike the fictitious portrayal in the film 'The Dish' there were many CSIRO staff involved, both at Parkes and elsewhere.
Parkes staffer Neil 'Fox' Mason, who was seated at the control desk, guided the telescope without being allowed to turn around and see the incoming pictures on the TV monitor. It was essential for him to monitor the tracking of the telescope, in case the winds picked up again, threatening the signal reception.
More details, including an extensive article on the support mission and video clips of the television broadcast, are available from On Eagle’s Wings: The Story of the Parkes Apollo 11 Support.