When Distant Voyagers Calls Home

Not many people can make the claim that they were there, in the very control room, as signals came in from the robot explorers sent forth to visit the other worlds in our Solar System.

Blasted out into the darkness of space in search of the answers that have driven our curiosity for tens of thousands of years – these faint signals, some of which are many times weaker than your home Wi-Fi, have been beaming in Earth’s direction from across the lifeless, cold gulf of interplanetary space where the quietness stretches for billions of kilometres.

Some of us were not even born, as a few of our robotic explorers - tasked with their enormous missions of in-situ observation and documentation of the planets in the Solar System - were sailing past the Gas and Ice Giants of the outer solar system.

But Gordon Clee can make this claim.

Gordon has been at the controls of the NASA's Canberra Deep Space Communication Complex (CDSCC) for over 34 years and was there as the first signals observed by humanity, came in from Jupiter, Saturn, Uranus, Neptune, Pluto and even Arrokoth.

Even now, as several of these spacecraft race away from the planetary bodies of the Solar System and start to enter interstellar space, Gordon sits steady at the helm as a DSN Link Controller, sending and receiving the feeble signal keeping humanity connected with distant explorers, from a time gone past. In more technical terms, Gordon’s role involves configuring, operating, controlling and monitoring the antennas of the CDSCC to point and communicate with spacecraft across the solar system and beyond.

“Being here for 34 years, the first planetary body encounter is always special. But I think my favourite would have to be the Curiosity mission - when it landed on Mars, as far as cool moments are concerned,”

“I was operating one of our 34-metre dishes, and I was tracking Mars Odyssey and it wasn't until we were halfway through the support that I realised that the images that I could see were being relayed from the surface of Mars, via the Odyssey orbiter to my station.”

Then there’s Barbara Peters, who has also contributed to the success of every NASA and other agencies deep space missions - from multiple lunar and Mars missions, planetary probes to Jupiter and Saturn and of course the Grand Tour by the twin Voyager spacecraft. 

“I’ve been asked many times, what special moments I can recall or if I have a favourite mission,”

“They are all special to me. These missions mean so much to the scientists and engineers who designed, built and fly them. It’s just an honour to play my small part in their success.”

Her role started as a DSN Link Controller almost 25 years ago at the CDSCC and since then, Barbara has been talking with our robotic travellers. 

“My first two applications were not successful, but I was convinced that this was the job for me and so I applied a third time and got it.”

Barbara has now been a Link Operator at the Canberra Deep Space Communication Complex for the past 25 years.

Coming from a background in Communications and Electronics, Barbara worked as an oil rig communications officer before moving to the Australian National University as an electronics technician.

Barbara never shied away from the challenge of working in what was, at the time, thought of as traditionally male-dominated fields.

“I found that after I had my children, I wanted to seek a role that would balance with my lifestyle and expertise and the position came up at the space tracking station.”

Since the launch of Pioneer 10 in 1972, our understanding of the solar system beyond Earth - including the thousands of images that have opened our eyes in wonder - have come through these channels, with people like Gordon and Barbara monitoring the health and telemetry of the in-situ observatories in the outer reaches of our system. 

Only a handful of locations around the world are equipped to communicate with our explorers today, as they continually sail onwards beyond their destinations – having served their mission objectives and still, reporting in on every new frontier they cross.

This network of communication stations is known as the Deep Space Network (DSN), with three primary locations set across Earth, separated by 120-degrees, providing the ability to continually provide coverage across the entire sky over a 24-hour period.

In early December, I spent a day with Glen Nagle, Outreach and Administration lead at the southern hemisphere DSN facility, located just outside Canberra, in the Tidbinbilla Valley. The facility has over the last ten years been directly managed by Australia's science agency, CSIRO.

Cocooned by the natural surrounding mountain ranges that provide radio interference protection, the location is surrounded by small rural hills, where fields of pale yellow tall grass grow at the base of gentle green hills and the road vanishes at a distant point ahead.

Glen’s been at the Canberra DSN for nearly 18 years, but as we walked around the grounds of the facility – it felt as if he had only started yesterday – emanating with excitement and nostalgic knowledge. For him, it was sharing the pride his passion had given him, to be amongst some of history’s greatest moments as humanity reached for the stars.

For me, it was like I was transported back to those exact moments when humanity came together, united through triumph or potential tragedy, that gave me goosebumps for my entire visit that day - even if I had not yet been born during some of these significant events.

Originally, three portable tracking stations were designed to track the first satellite launched by the United States (Explorer-1), situated in Nigeria, Singapore, and California. At the time, it was run by the Jet Propulsion Laboratory (JPL) - which fell under the command of the US army. 

It was during this period that the US Government recognised the value in establishing a central civilian-based agency for all space exploration programs, generated from its military branches: the Air Force, Navy and Army - and thus, NASA was established in October of 1958. By December of the same year, JPL would be transferred over to NASA - tasked with the design and implementation of lunar and planetary exploration using robots. 

The concept of a deep space network (for communication) was developed as a means to be more efficient (costs, processes, learnings) for future objectives - the alternate approach was each mission would be required to establish its own costly communication network. Foreseeing this value, NASA established the global DSN, announcing formally it would lead in deep-space missions in December of 1963. 

The purpose of the DSN is to send commands and receive data, as well as track and monitor the health and safety of distant spacecraft as they travel along their journeys through and beyond the Solar System. However, the three global facilities also enable and participate in important advancements of scientific research - for example, measuring radio signals between the spacecraft and Earth can better improve the understanding of distant locations in the Solar System, what lies in between the planets and moons or test our understanding of gravity.

Radio and radar instrumentation development and testing is another area of science and engineering that the DSN facilities have continually added value to since the early 1960s, becoming world-leaders in the advancement of low-noise amplifiers; tracking, telemetry and command systems; large parabolic dish antennas; digital signal processing and deep space navigation. 

To date, the DSN still makes the longest-distance calls in human history, utilising the world’s best and most sensitive scientific telecommunications systems to speak with the two Voyager spacecraft - now said to be beyond the Sun’s solar wind reach and entering interstellar space. 

The DSN is able to do this by ensuring continual, round-the-clock coverage across the sky using three tracking stations:

• Goldstone Complex - located in California
• Canberra Complex - located just outside Australia’s capital city
• Robledo de Chavela - located outside Madrid, in Spain

Each of the DSN facilities is equipped to look after all missions during their allocated time slots - that is to take control of all global DSN antennas and manage through the one complex before handing over to the next. 

As Glen described this, confusion set in - prior assumption and understanding had dictated that each facility would look after their own telescopes with rotating local teams to ensure continual coverage. 

The genius of this idea was made evident when Glen and I walked into the control room of the Canberra DSN facility. It had everything you would expect for a typical control centre - hanging large TV-screen with tables and graphs; workstations with five-six monitors resembling scenes from the Matrix films and clocks with different global time zones ticking over. 

But amongst all the technicality, flashes of humanities and a co-working team were present - in the centre of a room, standing high above a table a small, 1m Christmas tree wrapped in tinsel stood tall. At a few work stations, staff had personal belongings like photos of family members or personalised cups peppered across the clean, tidy desks. Along the floor, circumnavigating the outside of the workstations - rows of LED Christmas lights flashed on and off in a spectrum of colour.

Here is where I caught up with Gordon who described how he originally started working at the CSIRO Parkes radio telescope, roughly 340 km north-west of the Canberra DSN, working in the visitor centre.

It was when Voyager was about to cross paths with Uranus in 1986, that Gordon was approached to work down at the Canberra facility, handling tapes as a first look into operations. After reaching out that he’d like to work in the city, a new position was created revolving around documentation at the Canberra DSN, before being offered a role in comms work.

One day his supervisor approached Gordon and asked if he’d like to run the antennas at the deep-space mission facility - and he hasn’t looked back since. 

“I remember seeing the shots of the big cliffs on Miranda [one of Uranus’s Moon] and just being blown away by it - I thought to myself, wow - this was received on Earth 14 minutes ago, and now we’ve got that picture,”

Gordon would proudly experience a career full of these special moments as the data streamed in, and changed our understanding of the Solar System. I couldn’t help but think of how exciting it must have felt, being present for so many groundbreaking moments in science history, some of which (in particular the visit to the Ice Giants) have not been experienced by anyone since.

In fact, a sense of pride in achievement radiated across the whole facility. Located just outside the control room, a number of memorable plaques tell the story that commemorates the human exploration of space over the last 60 or so years.

Missions to the inner and outer planets, missions with humans that succeeded and others that failed. It was all there, mirrored in plaques like a precious time capsule of accomplishments.

Canberra DSN is a big site - and as we drove between the historic telescopes and buildings, the quirky names of the roads amplified the context of the setting. Names like Discovery Drive, Comet Place, and The Milky Way are juxtapositioned against the wide-open flats that turn into distant hills, surrounding the complex.

The Coolamon Ridge, Urambi Hills, and Bullen Range all help shield the facility from Canberra city’s radio frequency interference (RFI) - generated only 20km away. Whilst some of the biggest dishes in the world reside here at Canberra DSN, the signals they are collecting are extremely weak, only one-tenth of a billion-trillionth of a watt due to the vast distances they must travel. So the naturally surrounding semi-mountainous, bowl-shaped terrains that protect the antennas from RFI is welcome, and a feature of all three DSN global facilities. 

The first thing that draws people’s attention upon arrival at Canberra DSN, are the large antennas - their size and shape transporting visitors to memories from science-fiction movie scenes. The large white dishes standing tall and bright against the background - often slowly slewing to a new target or tracking the incoming signal of a spacecraft message.

In fact, all three global DSN facilities feature a number of three antenna designs - distinguished by their size and purpose. 

The largest of these at the Canberra facility is designated Deep Space Station (DSS) 43 - a 70-meter diameter antenna that stands at a height of 73 meters. The antenna’s dish is so big, you could fit an Olympic pool within it and still have 10 meters to spare on either end. Weighing in at approximately 3,000 tonnes - the reflective paraboloid covers a surface area of 3.85 square kilometers, maintained to a precision of 1cm - ensuring absolute minimal interference with the operations the antenna performs. 

Its sheer size has earned this impressive structure the largest steerable parabolic radio telescope in the Southern Hemisphere, only just surpassing the Parkes Radio Telescope (64m diameter).

However, unlike the Parkes Dish, DSS 43 can both receive signals from deep space and transmit signals back out, giving it an advantage for missions requiring commands to be sent to robotic explorers - especially those with southern declinations.

There are three active 34-meter dishes at the Canberra DSN facility - which come in the beam waveguide design - where the transmission and reception equipment are located underground, and radio signals are guided down by reflecting mirrors, much like a giant periscope. 

Glen talks me through the advantages of housing instrumentation underground, highlighting how the weight on the antenna is reduced - which minimises strain, wear and tear. He also indicates how it helps make maintenance much easier and safer to access, with technicians no longer required to climb high into the structures. 

Some added benefits are that the sensitive instruments are not exposed to the harsh variations of the Australian climate as well as further isolating the electronics from unwanted radio noise.

The last antenna on-site happens to also be Glen’s favourite - the now decommissioned DSS 46 which features a smaller 26-meter dish on top of a unique X-Y axis mount - two interlocking horseshoe rings that allow the telescope to both point at very low elevations and track objects across the sky quickly. 

Glen explains how this historical antenna has played a very important role in previous missions as we walk to its four base legs, cemented into the ground in large concrete blocks.

Towering 35-meters above me, this famous dish was once known as the Honeysuckle Creek Antenna, and today forms part of a legacy of the human space story.

Most Australian’s would be unaware that within 3 hours drive of Sydney, residing on Canberra’s doorstep is one of the most historically important space communication facilities in the world.

Since the early 60s, the Canberra DSN has received signals from humanities endeavours to explore the cosmos, including:

• The Apollo program, inclusive of the Apollo 11 moon landing
• Missions to the outer Solar System such as Voyager, Pioneer and New Horizons
• Cassini’s epic mission to Saturn

Today, over 30 missions continue to stream data through the antennas in Tidbinbilla, including Martian orbiters, Jupiter’s Juno, several solar observatories and exoplanet-hunting spacecraft. All three global DSN stations are always in operation and online visitors can see which spacecraft each antenna is talking to through a publicly available website. 

The first eight minutes of vision of the Apollo 11 moon landing - including Neil Armstrong’s immortalised words and first step, came in through the Honeysuckle creek antenna before they were broadcast out to the world (the Parkes Dish picked it up after this). Though it wasn’t just the all-important television images that were being received - telemetry data from both the Eagle and the Columbia crafts in lunar space, and the health of the three astronauts was received by this antenna.

Another important and ongoing mission that the Canberra DSN manages is one of humanity’s most iconic - our further object that currently sails away from the Sun and leads our first steps into interstellar space. The Voyager 2 mission. 

Voyager 2 left Earth in 1977 to travel to the outer planets of our Solar System. First, it visited the Gas Giants Jupiter and Saturn, which were also visited by Voyager 1 and the Pioneer spacecraft. However, the perfect planetary alignment also provided an opportunity for Voyager 2 to visit the Ice Giants, Uranus, and Neptune - still the only human-made object to do so to this day. 

After completing its planetary missions, Voyager has continued onwards with recent reports that it has now officially left the outskirts of the Solar System and entered into deep, interstellar space. It’s currently over 18 billion kilometers from Earth and moving at a velocity of approximately 55,000 km/h.

Remarkably, of its 10 original instruments, five continue to operate - even after 42 years of travelling through space - beaming in what the craft is observing as it crosses these new, uncharted frontiers in the direction of the southern constellation, Pavo. 

Due to its very south location in the sky, the only DSN tracking station that can currently communicate with Voyager is the Canberra facility. Whilst other antennas at Canberra DSN can receive Voyager’s extremely faint signal, only the 70m DSS 43 is capable of transmitting signal commands to the spacecraft, which moves away from the Earth by over 1.3 million kilometers per day. 

Earlier this year, Voyager 2 gave NASA scientists and DSN operators a scare, when it tried to execute a regular command - rolling 360-degrees to re-calibrate its magnetometer - a maneuver it has completed many times before. 

Through smart programming built into the spacecraft’s brain, the computer shut itself down to allow it to preserve energy during the maneuver - which caused a scare to the entire space science community. Was this it? Was this the end of one of humanities furthest probe and a chance to learn about the beyond?

Thankfully, scientists and engineers worked through painfully long wait periods (the light travel time is about 17 hours each way, so sending commands takes 17 hours to get there and then the response takes 17 hours to get back), and eventually brought it back into nominal operating levels. The entire ordeal has been streaming back and forth through DSS 43 at the Canberra DSN.

DSS 43 has just been powered down for a period of 10-months as instrumentation and equipment are upgraded to prepare the antenna for its important role it will play in NASA’s new frontier - the Artemis program - which will see the first woman walk and next man return to the Moon by the mid-2020s. 

The global space community is anxious about losing our only umbilical cord of communication with Voyager 2 - but the upgrades are a necessity to keep the telescope in optimal condition to continue with operations.

Australia’s unique position - and the excellent infrastructure managed by the CSIRO at the Canberra DSN will once again play a pivotal role in humanity's next steps into the cosmos. Already operating across 30 missions, the station will be pivotal to future exploration robots, sent back into the darkness of space. 

It’s hoped that we’ll one day also send our next generation of robots to the Ice Giants of the outer solar system, which will change our perspective of our place in the Universe once more. 

As I drove away from the facility, some lasting words from Gordon stayed with me that day. He said “I like the fact that what we are doing here today, go into the textbooks of science next year” and it made me think about how much our knowledge of the Solar System has changed even during my own 30-odd years of understanding the space program. 

My visit to the Canberra DSN centre was over - and I smiled ear to ear, feeling so much more enriched that I was able to hear about the lives of the people involved, and the wonderful infrastructure that has played such an important role in our shared space history. 

It also filled me with a sense of pride to know that Australia has contributed to this momentous record and our country’s vital role in the triumph, tragedy, discovery, and knowledge of humanity’s space programs will continue.

All of this, from our own backyard.