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And in 2017, Australia re-joins the Space Race . . . albeit with a hiccup or two! Three tiny satellites, built by Australian university students, were meant to enter orbit last April. But no sooner than they were they deployed from the International Space Station, they disappeared! Tracking them down (or at least two of the three) is a story of high-tech detective work and international co-operation. by ROSS TESTER An artist’s impression of the UNSW EC0 Cubesat leaving the International Space Station. (Courtesy UNSW) A t 1am Sydney time on Tuesday 19 April, a NASA mission to resupply the International Space Station (ISS) blasted off aboard an Atlas 5 rocket from Cape Caneveral, USA. Along with sustenance for the ISS personnel, part of the cargo included 36 tiny satellites called “Cubesats”. Each is about the size of a shoe box and weighs less than 2kg. Their purpose was to carry out the most extensive measurements ever undertaken of the thermosphere, a region between 200 and 380km above Earth. This poorly-studied and usually inaccessible zone helps shield Earth from cosmic rays and solar radiation, and is vital for communications and weather formation. (SILICON CHIP has published two articles on Cubesats and their even smaller cousins; “Reach for the Sky” in March 2015 www.siliconchip.com.au/Article/8398 and “Controlling a miniature satellite” in February 2014 www.siliconchip. com.au/Article/6126). Australian Cubesats Three of the Cubesats were built by students from Australian Universities: UNSW-EC0, built by UNSW’s Australian Centre for Space Engineering Research (ACSER); INSPIRE-2, by the University of Sydney, UNSW and the Australian National University; and SuSAT, by the University of Adelaide and the University of South Australia. Deployment from the ISS went completely as planned . siliconchip.com.au . . except for one tiny detail. The three Australian Cubesats – along with several others – had simply disappeared! Within 30 minutes of deployment from the ISS, they were meant to transmit a beacon. But no signal was detected by the ground teams at UNSW’s Australian Centre for Space Engineering Research (ACSER) or the ANU when the Cubesats flew over Sydney, which they were supposed to do twice a day. Flat batteries? The ACSER team began to suspect the Cubesats’ batteries might be to blame. In the nine months since both Cubesats had been dispatched to Europe for testing, and eventually to the US for launch, they might have lost partial charge: enough that they were now unable to extend the antennas. With their antennas stowed, their beacons would then be too weak for the UNSW or ANU ground stations to detect. “If batteries were the issue, the satellites have solar panels and should have been able to recharge,” said Joon Wayn Cheong, a research associate at UNSW and technical lead for both Cubesats. “But that would have taken just one or two orbits. Yet, after almost a week, we still heard nothing. Clearly, something else was wrong.” “It was like something out of Apollo 13,” said Elias Aboutanios, project leader for UNSW-EC0, the first Australianbuilt satellite in 15 years to go into space. “Our satellite was orbiting at 27,000km/h almost 400km Celebrating 30 Years October 2017  23 Ben Southwell, from UNSW, putting the finishing touches to their Cubesat, UNSW-EC0, before it was shipped overseas for testing. It was launched aboard an Atlas 5 rocket from Cape Canaveral, bound for the International Space Station and then deployment into Earth orbit. It gives an excellent idea of the “huge size” of Cubesats! above our heads. We couldn’t see it, couldn’t inspect it, and had almost no data to work with.” The engineers theorised that the satellites might be trapped in a vicious discharge/recharge loop: they didn’t have enough power to extend antennas but could not recharge completely because they were repeatedly trying to deploy antennas and stabilise orientation, draining the batteries again and again. So the ACSER team wrote software commands telling the Cubesats to power down and wait until being fully recharged before deploying antennas. But before the commands could be sent, the engineers needed to find more powerful transmitters that the satellites – operating with stowed antennas – could “hear”. Aboutanios, who is deputy director of ACSER, reached out to the Defence Department, Optus, the CSIRO and NASA but no equipment was immediately available or could broadcast on the right frequencies. Meanwhile Cheong, who has an amateur radio licence, contacted his worldwide network. That’s when Jan van Muijlwijk came to the rescue. The sound technician near Groningen, in the Netherlands, had access to the Dwingeloo radio telescope, a restored 25-metre dish from the 1950s that was once used for astronomy and is now run by amateur astronomers and amateur radio enthusiasts. Problem was, van Muijlwijk could only help on week24 Silicon Chip ends, which meant a tense wait. One down, two to go! On the first attempt, on Saturday 10 June, the Dwingeloo dish detected a weak signal from INSPIRE-2, and immediately uplinked the new commands. But when the Dutchman pointed the dish at UNSW-EC0, there was only silence. On INSPIRE-2’s next orbital pass, at midnight on Sunday 11 June, a clear beacon was detected by the Dwingeloo dish in the Netherlands and by former UNSW engineer Barnaby Osborne, now at the International Space University in France, and later by INSPIRE-2 team member Dimitrios Tsifakis at ANU, along with ham radio operators in Spain, the US and Australia. ACSER’s team at UNSW, who had managed the ground segment for the INSPIRE-2 project, were elated. But also stumped. Why was UNSW-EC0 still silent? Had they identified its problem, or was something else wrong? Had some other component failed? Would they ever be able to contact the satellite? Aboutanios, Cheong and their UNSW colleagues – Ben Southwell, William Andrew, John Lam, Luyang Li and Timothy Guo – regrouped to review what they knew, and work through more scenarios. They also looped in Osborne in France and Tsifakis in Canberra. To find ‘Echo’ – as they now dubbed their satellite – the team had relied on positioning data from NORAD (North Celebrating 30 Years siliconchip.com.au American Aerospace Defence Command), which tracks and catalogs objects orbiting Earth. The Cubesats had been shot out of the ISS in threes, and NORAD had detected this. It had then waited for the three Cubesats to drift apart enough that they could be tagged with their names and positions. But what if NORAD had mislabelled UNSW-EC0? Could they be listening for – and transmitting commands to – the wrong satellite? They went back through the NORAD data and identified the other two satellites deployed at the same time – Nanjing University’s NJUST-1 and University of Colorado’s Challenger – then asked van Muijlwijk to point his dish at the other two Cubesats and listen for UNSW-EC0’s beacon from those instead. Success for another “As soon as the Dwingeloo dish pointed to what the NORAD data said was the Challenger Cubesat, it detected a weak signal that was clearly from UNSW-EC0,” recounted Cheong. “So they fired off the reset commands. And on the very next orbital pass, they received a beautiful, clear signal from UNSW-EC0.” Aboutanios mused: “For more than three weeks, we were looking in the wrong part of the sky for our satellite – we couldn’t have known that.” “But the procedures we put in place, the scenarios we ran and the solutions we developed, they all paid off. You could say we succeeded by engineering the heck out of this.” University of Sydney’s Iver Cairns, leader of INSPIRE-2 team, said it had been an agonising experience. “It was intensely frustrating, and surprising, to hear nothing from INSPIRE-2 or UNSW-EC0, since both are very robust satellites that passed their pre-flight tests with flying colours”. “But the recovery effort, led by our UNSW and ACSER colleagues, was a real international team effort, and something we should all be very proud of.” UNSW-EC0 and INSPIRE-2 now join the 20 other QB50 satellites successfully contacted so far. They were joined on Friday 23 June by another eight QB50 Cubesats, launched into orbit by India’s Polar rocket from the Satish Dhawan Space Centre north of Chennai. Still no SuSAT Of the 28 QB50 Cubesats originally deployed from the ISS in May, eight have still not been heard from – including Australia’s third Cubesat, SuSAT. “We’ve contacted our colleagues in Adelaide to see if we can help,” added Aboutanios. The two recovered Australian satellites are now going through a long testing process leading to their commissioning. Later this year, they will join other active QB50 satellites in collecting scientific data. The three research Cubesats are the first Australian satellites to go into space in 15 years; there have only been two before: WRESAT in 1967 and Fedsat in 2002. “We’ve got more hardware in space today than Australia’s had in its history,” said Andrew Dempster, director of ACSER and a member of the advisory council of the Space Industry Association of Australia. “The QB50 mission shows what we can do in Australia in the new world of ‘Space 2.0’, where the big expensive agency-driven satellites are being replaced by disruptive low-cost access to space.” SC UNSW student John Lam at VKI Headquarters in Delft, Netherlands, preparing the UNSW-EC0 satellite for final integration and then shipping to the USA for inclusion in the ISS-bound cargo. siliconchip.com.au Celebrating 30 Years October 2017  25