Milestone-Proposal:Deep Space Station 43, 1973

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Docket #:2022-12

This Proposal has been approved, and is now a Milestone

To the proposer’s knowledge, is this achievement subject to litigation? No

Is the achievement you are proposing more than 25 years old? Yes

Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes

Did the achievement provide a meaningful benefit for humanity? Yes

Was it of at least regional importance? Yes

Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes

Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes

Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes

Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes

Year or range of years in which the achievement occurred:


Title of the proposed milestone:

Deep Space Station 43, 1972-1987

Plaque citation summarizing the achievement and its significance:

First operational in 1972 and later upgraded in 1987, Deep Space Station 43 (DSS-43) is a steerable parabolic antenna that supported the Apollo 17 lunar mission, Viking Mars landers, Pioneer and Mariner planetary probes, and Voyager's encounters with Jupiter, Saturn, Uranus, and Neptune. Planning for many robotic and human missions to explore the Solar System and beyond has included DSS-43 for critical communications and tracking in NASA’s Deep Space Network.

200-250 word abstract describing the significance of the technical achievement being proposed, the person(s) involved, historical context, humanitarian and social impact, as well as any possible controversies the advocate might need to review.

IEEE technical societies and technical councils within whose fields of interest the Milestone proposal resides.

In what IEEE section(s) does it reside?

Australian Capital Territory Section

IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:

IEEE Organizational Unit(s) paying for milestone plaque(s):

Unit: Australian Capital Territory Section
Senior Officer Name: Ambarish Natu

IEEE Organizational Unit(s) arranging the dedication ceremony:

Unit: Australian Capital Territory Section
Senior Officer Name: Ambarish Natu

IEEE section(s) monitoring the plaque(s):

IEEE Section: Australian Capital Territory Section
IEEE Section Chair name: Ambarish Natu

Milestone proposer(s):

Proposer name: Ambarish Natu
Proposer email: Proposer's email masked to public

Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.

Street address(es) and GPS coordinates in decimal form of the intended milestone plaque site(s):

421 Discovery Drive, Paddy's River District ACT 2620, 35°24'08.4"S 148°58'52.9"E

Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.

Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. In the public entry point’s plaque display garden.

Are the original buildings extant?

Yes. The actual site has been in operation since 1972, and it has seen two major upgrades.

Details of the plaque mounting:

The plaque will be mounted onto the face of a flat rock, and placed in the public entry point’s plaque display garden where there are other commemorative plaques.

How is the site protected/secured, and in what ways is it accessible to the public?

Because of the massive investment in the CSIRO Canberra Deep Space Communication Complex, it has heavy security. However, the public entry point’s plaque display garden is publicly accessible during at least business hours.

Who is the present owner of the site(s)?

Commonwealth Scientific and Industrial Research Organisation

What is the historical significance of the work (its technological, scientific, or social importance)? If personal names are included in citation, include justification here. (see section 6 of Milestone Guidelines)

The Tidbinbilla Deep Space Tracking Station, also known as Deep Space Station 43 (DSS-43), was constructed from 1969 to 1973 as a 64-metre diameter antenna. It was more than six times as sensitive as DSS-42, the original 26-metre antenna at the Canberra Deep Space Communication Complex (CDSCC) at Tidbinbilla near Canberra, Australia. The primary purpose of the station's antennas is to track spacecraft and space probes for NASA and other space agencies.

DSS-43 supported, as needed, the Apollo 17 mission to the Moon before the antenna's dedication and official opening in 1973. Viking 1 and 2 missions were also supported in June-July 1976 when they were the first human landers on Mars. The Canberra dish handles nearly 42% of all data emanating from celestial explorers like Voyager, New Horizons, and the Curiosity rover, and it has also enabled the world to see dazzling pictures of Mars and Pluto.

DSS-43 was extended from a 64-metre diameter antenna to a 70-metre diameter in 1987 to enhance its capabilities for the Voyager 2 1989 encounter with Neptune. It is the largest steerable parabolic antenna in the Southern Hemisphere. The massive structure, weighing more than 3000 tonnes, rotates on a film of oil approximately 0.17-mm thick. The reflector surface is made up of 1,272 aluminium panels with a total surface area of 4180 square metres. The outer panels are perforated, allowing rain and wind to pass through them.

NASA plans to send future generations of astronauts from the Moon to Mars, and DSS-43 will play an important role as part of NASA's Deep Space Network.

What obstacles (technical, political, geographic) needed to be overcome?

Communication with an object located outside of our solar system requires a dish with extraordinary technical accuracy, and this is made possible with an RMS surface flatness of 250 microns (.25 mm) and a pointing accuracy of 0.005 degrees (18 arc seconds). This accuracy, coupled with the dish’s gain of 74.8 db and extremely narrow beamwidth of 0.0038 degrees, together enables communications to the incredible distance from Earth of more than 23 billion kilometers when the Voyager spacecraft is beyond Pluto. No other dish in the southern hemisphere even comes close to these technical specifications.

As a result of the Voyager 2’s flyby of Neptune's moon Triton in 1989, its trajectory steered significantly southward relative to the Solar System's plane of planets, resulting in northern hemisphere antennas having no way of reaching it. As a result, DSS-43 in the southern hemisphere is the only dish on Earth able to communicate with Voyager 2, which is almost 20 billion kilometers from Earth as of 2023. When it is eventually updated with more sensitive receivers and more powerful transmitters, the DSS-43 antenna will continue to be able to communicate with the Voyager spacecraft (and others) as they travel deeper into interstellar space.

The obstacles that had to be overcome during the construction of DSS-43 were also exceptional. From the accuracy of the foundation of the site, to the building’s accuracy, and to the rotational structure of the telescope, together required a total systems accuracy across the base of the antenna of 0.25 mm. In RF systems communicating across the vast reaches of the solar system and beyond, mechanical accuracy is key to the success of the electrical systems. Even an error of +/- 0.1 mm would result in pointing errors in the tens of thousands of kilometers at the tens of billions of kilometers distance of the Voyager spacecraft. The accuracy requirement extends to the design of the antenna structure and the feedhorn, as well as to the center of axis of the feedhorn itself.

All of these aspects of the system's design and accuracy together enable communication over distances that were unthinkable before the inception of DSS-43 and its compatriots around the world.

What features set this work apart from similar achievements?

When it comes to making a long-distance call, it's hard to top NASA's Deep Space Network. It’s the largest and most sensitive scientific telecommunications system in the world.

The Deep Space Network - or DSN - is NASA’s international array of giant radio antennas that supports interplanetary spacecraft missions, plus a few that orbit Earth. The DSN also provides radar and radio astronomy observations that improve our understanding of the solar system and the larger universe.

The DSN is operated by NASA's Jet Propulsion Laboratory (JPL), which also operates many of the agency's interplanetary robotic space missions.

The Deep Space Network (DSN) is operated by NASA's Jet Propulsion Laboratory (JPL), which also operates many of the agency's interplanetary robotic space missions. The DSN consists of three facilities spaced equidistant from each other – approximately 120 degrees apart in longitude – around the world: Goldstone, near Barstow, California; near Madrid, Spain; and near Canberra, Australia, which includes DSN-43. The strategic placement of these sites permits constant communication with spacecraft as the Earth rotates – before a distant spacecraft sinks below the horizon at one DSN site, another site can pick up the signal and carry on communicating. Nearly 42% of all data emanating from celestial explorers like Voyager, New Horizons, and the Curiosity rover comes through DSS-43, whose communications operate in these bands: Transmit: X and S; Receive: X, S, L, and K.

The antennas of the Deep Space Network are the indispensable link to explorers venturing beyond Earth. They provide the crucial connection for commanding our spacecraft and receiving their never before seen images and scientific information on Earth, propelling our understanding of the universe, our solar system and ultimately, our place within it. Without the exceptional gain of the dish, coupled with its exceptional mechanical and electrical precision, it would be impossible to communicate with spacecraft beyond the edge of our solar system. Even today DSS-43 is unique in its ability to send commands to the Voyager spacecraft, and is key to our growing understanding of the environment of space beyond where any human spacecraft has flown.

Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.


Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to Please see the Milestone Program Guidelines for more information.

Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).

Please recommend reviewers by emailing their names and email addresses to Please include the docket number and brief title of your proposal in the subject line of all emails.