Australia installs first space laser optical ground station in southern hemisphere
Recently, my colleagues and I swung a half-tonne telescope onto the roof of the physics building at the University of Western Australia.
For a tense moment, my career hung from a crane hook.
The telescope is the first of its kind in the southern hemisphere and represents a new generation of space communications using lasers.
Dubbed the Western Australian Optical Ground Station (WAOGS), we hope it will be part of a global network receiving high-definition TV from astronauts on the moon, when NASA returns there in 2024.
So why do we need lasers in space?
It may seem hard to imagine in our age of global streaming services, but transmitting HD video from space is incredibly hard.
While Earth has seen a revolution in telecommunications, satellites and spacecraft are stuck in the era of dial-up internet.
In space, there's no 4G data connection. There are no fibre-optic cables drooping down from orbit.
Satellites transmit their data with radio frequency (RF) technology that has barely changed since Neil Armstrong zipped up his space-boots.
We rely on these satellites for communications, weather observations, crop monitoring, mapping, bushfire and disaster response, and a huge range of other applications.
Increasing data transmission from space is crucial if we want to benefit from this data and improvements in technology.
If our laser communications can fix this data bottleneck, we can free satellites to be more useful and also open up the possibility of super-fast space-laser internet being delivered to anywhere on the planet.
Why laser communications?
Laser communications have several advantages over radio, including significantly faster data rates and greater security.
Radio waves and light are both forms of electromagnetic waves, just of different frequencies.
The higher the frequency of the electromagnetic wave, the more information that can be transmitted each second.
The push to higher frequencies to transmit more data is the difference between 4G and 5G mobile phone networks.
Australian 5G networks can transmit data dozens of times faster than the older 4G networks. With more and more people demanding ever more from their internet connection, the 4G networks can not transmit data quickly enough (that is, they do not have enough "bandwidth") to supply everyone's needs.
The same is true for spacecraft. With an increasing number of satellites, each generating more and more data from ever-improving sensors and cameras, radio communications do not have enough bandwidth to transmit all of that data back to Earth.
A satellite equipped with a laser transmitter will be able to downlink its data to Earth at rates tens of thousands of times faster than it could with a radio transmitter, overcoming our data bottleneck problems.
Laser transmitters also have other advantages.
They are smaller and lighter than radio transmitters, which is important for spacecraft, where every extra kilogram adds tens of thousands of dollars to the launch costs.
Lasers are more directional than radio waves — they can be more precisely pointed at the receiver on the ground.
This means multiple spacecraft transmitting on the same frequency won't interfere with each other, as radio does.
And that data is much harder for an eavesdropper to intercept.
But the atmosphere is in the way
However, to make laser communications work, we have to overcome a major challenge: atmospheric turbulence.
Slight differences in temperature, pressure and composition modify the refractive index of the air and deviate the path of the beam.
This is why you see shimmering above a hot road, and why stars twinkle.
The atmospheric turbulence can degrade the quality of the laser beam link and in turn limit the rate at which data can be sent.
One solution to this is "adaptive optics", which was previously developed for studying galaxies in the deep universe.
Large astronomical telescopes detect the distortion caused by the atmosphere and deliberately deform their mirrors in the opposite way.
By counteracting the distortion, the telescopes capture a clearer, sharper image.
The same techniques can help laser receivers capture a good quality link through atmospheric turbulence.
Super-fast space internet
If the problems caused by atmospheric turbulence can be overcome, this will open the way to super-fast space-based internet on Earth.
Light travels about 50 per cent faster in the vacuum of space than it can through a fibre optic cable, so data going via satellites can get to the other side of the globe a fraction of a second faster than through the undersea cables that currently underpin international communications.
This means satellite links have lower "latency".
Low latency is important for financial markets, where a few milliseconds can make millions of dollars difference to the value of stocks.
This is the economic driver behind Elon Musk's Starlink network, which will eventually comprise tens of thousands of communications satellites.
In the next few years we can expect to see an explosion of companies launching large numbers of communications satellites, all vying to shave milliseconds off the time it takes to get high-value data between continents.
An Australia-NZ optical ground station network
The telescope erected on our physics building is the first in a planned network of optical ground stations across Australia and New Zealand.
To find out more, I spoke with Kate Ferguson, a member of the Australian National University's Institute for Space and one of the people helping develop the Australasian Optical Ground Station Network (AOGSN).
Dr Ferguson says the network will eventually be made up of four ground stations in Western Australia, South Australia, ACT and New Zealand.
The stations will work together to "hand over" a satellite from one station to the next as it passes over Australia, coming into view of one ground station as it passes out of view of another.
By spreading the stations out, she says, there's a lesser chance their operation will be interrupted by weather.
The AOGSN is currently under construction, but it will be a few years before the network reaches its full capacity, as technologies are developed and tested.
It's envisioned the AOGSN will be the backbone infrastructure for space-based internet communications in Australia and New Zealand.
This could be of particular benefit to those in rural areas of Australia who don't have access to fibre-optic broadband speeds.
Whoever builds the necessary infrastructure first stands to make a lot of money.
Bob Gough, head of business development with the satellite communication company Goonhilly Earth Station, which has supported the installation of the WAOGS, explained the value of the global space economy was expected to triple over the next 10 years.
Australia's share of the global space economy market grew by 30 per cent from 2019 to 2020, and it is hoped that establishing capability in laser communications will see that trend continue.
"It is our vision that Australasia becomes the southern hemisphere hub for all advanced communications from the ground to low Earth orbit, the Moon and beyond," Dr Ferguson said.
Streaming HDTV from the moon
NASA's Artemis missions aim to return astronauts to the Moon in 2024, before establishing a permanent lunar colony as a stepping stone to crewed missions to Mars.
NASA expects the Artemis missions will need to transmit over 3,000 times more data back to Earth than the Apollo missions of the last century.
This data includes critical spacecraft telemetry, scientific data, and video of the astronauts.
NASA has already tested laser communication from spacecraft in lunar orbit in preparation for human missions.
If the WA Optical Ground Station is part of the lunar mission, it'll be continuing a grand Australian tradition.
When Armstrong and Buzz Aldrin first stepped onto the Moon during the Apollo 11 mission in 1969, the TV images were received by a tracking station at Honeysuckle Creek in the ACT, and the CSIRO's Parkes radio telescope (also known as Murriyang or 'The Dish') in NSW.
Sascha Schediwy, head of the research group responsible for designing and building the WA Optical Ground Station, believes lasers will play a crucial role in the next human missions to the Moon.
"It's likely to be how we'll see high-definition footage of the first woman to walk on the Moon," Dr Schediwy said.
Dr David Gozzard is an experimental physicist in the International Centre for Radio Astronomy Research (ICRAR).
He is also one of the ABC's Top 5 scientists for 2021.