Transforming University land into a cutting-edge field station

Over the past two years, Associate Professor Nick Rattenbury and Dr Joe Ashby have been building the Taiaho Observatory, transforming University land in South Auckland’s Ardmore into a cutting-edge field station for free space optical communications (FSOC) research.

The FSOC project was set in motion after a conversation with Professor Anna Moore, the Director of the ANU Institute for Space (InSpace) at the Australian National University, about a group of Australian universities that are collaborating on a network of telescopes across Australia.

Nick is the principal investigator overseeing the project and sourcing funding for the research. He explains that the conversation with Anna Moore led to an introduction to the German Space Centre (DLR), which is a world leader in Free Space Optical Communications. New Zealand was already interested in developing closer research links with Germany and looking for research ideas, so the timing was favourable and eventuated in funding streams, which successfully targeted working specifically with the DLR.

“It’s a project I got excited about because it involved things I’m really interested in, specifically telescopes. It gave us the opportunity to work with our colleagues in Australia, and it’s clearly aligned with one of the strengths of the physics department here, which is laser communications and photonics,” says Nick.

He credits Joe Ashby as the person who is driving the research progress and managing the team of students working on related research.

“In the field of optical communications, there’s a lot of science to be done on the measurement of atmospheric turbulence. Even in a completely clear sky, you’ve got this turbulent effect that distorts the lasers as they come in,” says Joe.

Joe also managed the commissioning of the dome, which is essentially on a permanent loan or a gift from the Defence Science and Technology (DST), and the technology installation on site. This process faced its fair share of challenges, ranging from mechanical to organisational, and was further complicated by the less-than-ideal existing infrastructure at the Ardmore site.

Inside the dome, the team has been collaborating with a group that was sent to New Zealand by the DLR to install the Small Optical Ground Stations Focal Optics Assembly.

“The actual technology installation, and commissioning that we did in collaboration with the DLR was probably the fastest I’ve ever seen something like that get put together. They were here for three weeks. I think we had pretty much everything installed by the end of week one,” says Joe.

The team saw its first signals in mid- February, from the DLR satellite, meaning, in theory, they have commissioned the ground station and have proven its capability.

The student projects focus on: atmospheric turbulence to better understand and measure how atmospheric conditions affect laser signals and Optical Communications; and Satellite Laser Identification Systems, centred around a student-built satellite prototype designed to broadcast laser signals for identification.

The goal is to develop the capabilities for performing quantum optical communications and advanced adaptive optics systems to correct signal distortions due to atmospheric turbulence. The team has established the first New Zealand FSOC node, forming part of an Australasian Optical Communications Ground Station Network.

Nick explains, “Free space optical communications is talking between the Earth and orbit using laser light as opposed to radio frequency light.”

There are many benefits to this technology; it’s faster, it can process more information and, significantly, it has the ability to be more secure.

“The thing that you can do with an optical communications link is that you can include a level of security which is not available for any other type of communications,” says Nick.

He explains the difference is that radio frequencies are broadcast everywhere, requiring the application of encryptions, which are increasingly less secure as technology evolves. In contrast, the use of laser communications introduces a level of security that can not be compromised by technology because it’s a function of fundamental quantum mechanics.

“There’s a way of sending the communication so that the two people who want to communicate with each other know whether their communication has been eavesdropped… and that’s something the eavesdropper can do nothing about,” says Nick.

Joe explains that a phenomenon driving much of the investment in this research is Q-day (Quantum Day). Scientists predict quantum computers will soon be theoretically capable of quickly decoding standard encryptions, presenting a significant risk to currently considered secure communications.

“We believe they will be able to decrypt all current encryption protocols in a matter of minutes instead of taking thousands of years,” says Joe.

The biggest challenge for the technology is the cloud and atmospheric interference. Even with clear conditions, dropouts can occur due to the Earth’s atmosphere causing laser instability.

This is where the collaboration across nations is valuable for what they term ‘site diversity’. “If you have a group of telescopes separated by several hundred kilometres over a wide area, all working together as a network, then you can dodge the clouds at one site. For instance, if it’s cloudy in Auckland, then maybe Western Australia will be clear and able to see the same satellite during its next pass as it goes over,” says Nick.

While the project is largely collaborative, a level of secrecy is expected with significant technological advances. However, this is limited by the reliance on collaboration and information sharing necessary for the technology’s success.

“If you want to communicate worldwide, you have to develop standards. And those standards must be developed in conjunction with other people around the world who are working in the same area,” says Nick.

This is a hot topic of debate right now, given how critical security is to the success of the collaboration.

“Some sectors are looking into this very carefully, questioning, how do we possibly trust these communications when those communications go outside our own borders and our own control?”, says Nick.

Nick and Joe credit support from the DST and the DLR German Space Centre as an invaluable contribution that has made it possible to progress the project to where it is today.

“We are, in theory, fully operational. It’s just a matter of proving that before we announce it to the world that we are 100% ready to go,” says Joe.

He will be attending the International Aerospace Conference in Sydney, where they will be presenting their data on the capabilities of the network as well as the capabilities of each of the individual ground stations.

“This has been my first term as a postdoc after my PhD, returning to academia, and it’s been fantastic. The whole last two years have been thoroughly enjoyable,” says Joe.

“I think it’s fair to say that these have been the most exciting few years of my career, trying to run a project like this with people across two nations at least, and developing a group who are doing fun things with telescopes and lasers,” says Nick.