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At the begining of April 2026, NASA's Artemis II mission flew four astronauts to the Moon and back. This was the first crewed mission to the Moon since Apollo 17 in December 1972. A lot has changed since then and the Artemis II mission was a test of many technological developments. One of those was free-space optical communications. The Laser Communications team at the Australian National University's Research School of Astronomy & Astrophysics had constructed a new research facility at Mount Stromlo a couple of years earlier. The investment in the building and a 0.7m Alt-Az telescope was partially funded by the ACT Government's Priority Investment Program (PIP). That program intended to foster collaboration between research organisations and industry, and in our case it did exactly that. The facility, called the Quantum Optical Ground Station (QOGS), caught the attention of a member of a NASA team developing a similar system. Both were based on leveraging commercial off-the-shelf components to drive down the cost of building a ground station network. A combination of vision and perserverance lead to a formal agreement to allow QOGS, and the team at ANU, to participate in the Artemis II mission as part of the broader demonstation of optical communication at lunar distances.
NASA had three optical communications ground stations in the US at various states of readiness, namely Table Mountain in California, White Sands in New Mexico and the Low-Cost Optical Terminal (LCOT) in Maryland. LCOT and QOGS both had the Planewave RC700 telescope as their foundation. The significantly different longitude of the ANU station at Canberra offered greatly increased temporal coverage from the collective ground station network, but as a non-NASA facility there were many logistical and adminstrative hurdles that needed to be crossed. QOGS was also a new facility, and it didn't have the specific instrumentation suite required for communication with Orion, the Artemis II spacecraft. Investment from the ANU's Institute for Space and the Australian Space Agency supported a combination of component acquisition and in-house engineering to fit-out QOGS with the instrumentaton needed to support the mission. Somewhat unexpectedly, the LCOT ground station was descoped from participating in the demonstration. This was undoubtedly a huge disappointment to the teams from both Glenn Research Center (GRC) and Goddard Space Flight Center (GSFC) that had spent years developing their station's optomechanics, modem and control system. To their credit, and our benefit, both the GRC and GSFC teams turned their attention to supporting our effort to scramble to be ready in time for the launch. Experts in every field came to our site and seamlessly joined our small team. They graciously provided advice and guidance on assembling and testing our designs, as well as preparing us for the rigor of operating according to NASA protocol during the flight - an experience that was certainly new to us. Collectively we had a mountain to climb. The receive and transmit systems needed to be manufactured, aligned and validated. Our modem, a duplicate of the superb GRC-designed system, needed testing, tuning and calibrating. The launch date we were working towards was late 2025, and there were lots of critical long-lead time procurements dictating our production schedule. It took an enourmous effort from everybody, and the last six months was the most intense stanza of my career. Key NASA staff made many trips and stayed for long stints. A huge disruption to their normal lives. Sacrifice was everywhere you looked, but the intensity was addictive, at least for me, and the desire to succeed overwhelming. So was the fear of failing. We knew the mission was going to be the first opportunity to genuinely test many elements of the system. This seems almost unimaginable in restrospect, but we were part of a demonstration, and not mission critical. The two US stations were capable of both uplink and downlink communication. Uplink was descoped for QOGS relatively early in the design phase. This made our system best suited to downlink streaming video, as this is tolerant of packet loss. We still needed to have transmit optical systems, and the associated software control system, to produce the beacon that is critical for forging the link. This made timely comlpetion a less risky prospect but it didn't reduce the complexity all that much. Formally our agreement guaranteed only one hour to attempt to link with the space terminal on Orion. Although both organisations hoped we'd have many more opportunities than that, the plan months out from the launch suggested our first chance wouldn't arrive until day-4 of the flight. The launch date slipped multiple times, and as we got closer to lift-off the likelihood of linking earlier in the flight steadily grew. The NASA staff deeply embedded in our program were undoubtedly our greatest allies in this subtle shift of priority. As well as being extremely active participants in assembly and testing, they were trusted observers of progress and that helped senior leaders within NASA better understand the risk. Yet another reason why the strong GRC-GSFC-ANU collaboration was vital. A few days prior to the first possible launch window in April 2026, we completed setup of our temporary control room inside the CSIRO Mobile Operation Center, transitioned to a night schedule, and continued to rehearse the complex process of establishing the link. All of this assumed the transmit systems were coboresighted and the beam profile met the design specification. Both of these properties were impossible to confirm once they were mounted on the primary telescope. We knew we would have to trust the lab-based metrology that aligned each transmit unit and set its divergence, and a chain of calibration steps that co-aligned the final assembly of the four of them. We did not have access to a space terminal, or any other space-borne system, to do end-to-end testing and verification of this critical optical assembly. The blind pointing required of the ground station to establish a link was going to be blind in more ways than one. If the optical performance was poor then the system simply would not work. Specialist optical engineers had done everything they could with limited metrology equipment to produce a functional far-field beam profile, but there was uncertainty, and with it a great deal of anxiety about how our first link attempt would unfold. On the night of March 31st we monitored the launch preparation at Cape Canaveral and the countdown at mission control. It became increasingly likely the launch would go ahead at the very first opportunity, and indeed it did. Many of our ANU colleagues arrived at work on the morning of April 2nd and joined us to watch the successful launch. That dramatic 8-minutes put an end to speculation about the timeline. It meant we needed to be ready to go in 10 hours time. It also meant our NASA colleagues, and now dear friends, would be leaving us in 10-days time for the last time. A fact that was yet to sink in.
Our nine-member operations team returned at 6pm to setup ready for our first pass of Orion. It was cloudy, but forecast to clear in the early hours of the morning. We also received news that both US ground stations had successfully established a link with the space terminal, and that a link attempt would be made with QOGS at the end of the pass over White Sands. The clouds mostly cleared and around 2am mission control at Houston directed us to prepare to link. We slewed to track Orion's predicted trajectory and enabled the laser beacons. We did not see the downlink beam from the space terminal, and telemetry from the terminal confirmed it was not receiving power from our station. This was to be expected, as both US stations required significant pointing offsets to locate Orion. We configured spiral search parameters and began the slow process of scanning. The team scrutized every signal for any indication of the spacecraft, and the tension rose with every unsuccessful step of the search. There were so many factors that could lead to non-detection and virtually nothing we could do at this point except scan. On the seventh step there was a brief flash on the cameras in the transmit units. It was the unmistakeable signature of the laser emitted from the space terminal. A mouse click and a few frantic keystrokes quickly adjusted the telecope pointing. A few seconds later the spot on the cameras returned, but this time it stayed. The tracking loops were closed on the transmit and receive systems and the downlink comms signal was being fed to the detectors. The modem team called out that they were seeing counts, and that the modem was decoding, and that the decoding was error free. Mission control called out that the space terminal had entered the closed-loop tracking state, and that "we've got it". Collectively the burst of different voices was confirmation that the whole system was working. We'd successfully acquired Orion, established the link and were maintaining it. Jubilation was rapidly overtaken by an enormous sense of relief. We knew the spacecraft was not going to remain in a favourable orientation for very long, so the celebration was short and sweet. The experience of NASA staff within our team shone through again, and we tried to take advantage the surplus power to optimize the pointing and characterize the beacon beam profile. This achieved a small increase in effective power. An on-the-fly calibration that would be vital for the lunar distances just days away. Soon after we'd established a stable link mission control switched the video feed from the S-band radio to optical, and we saw the effect of the substantial increase in bandwidth on NASA's live YouTube channel. This also confirmed the adminstratively complex network link from ANU to mission control was working. At the first opportunity our combined ANU-NASA team had succeeded, not only in demonstrating the technology, but together we'd constructed a system with genuine operational capability. It was a fantastic result and soon after the link was broken by a roll of the spacecraft, the champagne corks were popped. The space terminal and all three ground stations reached an important milestone on day-1, but Orion was still quite nearby. The mission objective was to demonstate capability at lunar distances. Bolstered by the early success, mission control soon took a more ambitious approach. On day-3 we attempted to operate at the maximum possible data rate of 260Mb/s. At this point Integrity was approximately 340,000 km from Earth, about 80% of the way towards it's primary destination. We had intermittent interruptions to the link when beacon lasers triggered on error conditions, and a few minutes of confusion when the receiver control system lost lock and reacquired on a ghost image. Both issues were correctly identified and diagnosed by having many sets of eyes monitoring the system metrics. Over the first four or five days I spent my afternoons making minor changes to the control system software to, hopefully, resolve these issues. Although it's far from ideal to be changing software and deploying mid-mission, this was necessary, and a consequence of not being able to do end-to-end testing in advance. While I fixed bugs others analysed the telemetry data obtained the previous day. The focus was on determining if we had the predicted margin in the power budget to support the largest link distance, and it was looking good. On flight day-5 we got confirmation the optical communication program's Artemis II mission objective had been acheived.
The support NASA provided to ANU was phenomenal. They only ever wanted us to succeed. Every single person I interacted with was extremely professional, very talented, and genuinely personable. There were no egos on display, just individual altruism, good humour and good nature. The thousands of hours they contributed, both here and at home, was done entirely with their budget. Travel and accommodation costs likewise. A non-trivial injection into the ACT economy that may incorrectly be attributed to tourism. Financials aside, the collaboration did what you need them to do - leverage the best from both sides to deliver something neither could have pulled off alone. It also fostered some increadibly rewarding professional relationships. The kind that tend to spawn future collaboration. The Mount Stromlo weather conditions were not particularly favourable, but our team managed to establish a link to Orion on eight of the nine passes. Heavy rain completely wiped out any opportunity on flight day-8, and many other nights were impacted by patchy cloud. None the less we were able to deliver a few of the milestones for the entire optical communications program. On day three we operated at 260Mb/s at a link distance of approximately 340Mm. We were operating as the crew of Integrity surpassed the distance record previously set by the crew of Apollo 13. We also demonstrated 4K video streaming during the official hour set aside for us in the mission schedule. That occurred on flight day-7. It was not as seamless a demonstration as we'd have hoped, but a young NASA colleage showed outstanding diagnostic skills under considerable pressure, and proved the Orion-to-ANU portion of the link was working flawlessly. Knowing you'll only get one chance was a significant part of why this project was physically very demanding and very emotionally draining. Everybody within our team, or supporting us remotely, has every right to be enormously proud of their contribution and achievements. It was a privilege to be a part of an historic mission, but it's the friendships and the communal collection of many small personal triumphs that have forged the memories that will endure a lifetime.
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