Two tiny cube satellites orbiting out of contact and out of control around the Earth since May have been rescued by a team of UNSW engineers. NASA, CSIRO, Optus and the Defence Department weren't able to help, but a Dutch sound technician with access to a satellite dish from the 1950s stepped in to save the day.
This article was originally published on June 26 at 8:30AM.
In May, three Australian 'cubesat' research satellites were deployed from the International Space Station after being launched into space in late April as part of the QB50 mission, a spread of 50 tiny satellites positioned in the planet's thermosphere, a relatively high portion of the atmosphere. All three Australian satellites were nonresponsive after launch — the University of Adelaide and Uni of SA's SuSAT was successfully launched but did not contact its handlers, and both INSPIRE-2 from Sydney Uni, ANU and UNSW as well as UNSW's UNSW-EC0 did not originally ping a signal back to Earth.
In the weeks that followed, UNSW's ACSER searched for the cubesats in the thermosphere, theorising that their problem might be a battery issue — not enough charge to deploy a main antenna and communicate, with solar panels not getting enough power before each deployment attempt for it to complete fully — a vicious cycle of recharge and failure. Project technical lead Joon Wayn Cheong said that if satellites hadn't responded after a couple of orbits, the batteries likely weren't getting enough of a charge to complete that crucial antenna extension and stabilisation after each rotation and failing on subsequent attempts. An over-the-air software update was written to tell the satellites to power down and recharge fully, but it had to be delivered to the zone where the satellites were expected to be.
UNSW lecturer and ACSER deputy director Elias Aboutanios reached out to contacts at the Defence Department, Optus, the CSIRO and NASA, but wasn't able to get access to equipment that could broadcast on the right frequencies or that was available for the ACSER team to access at the appropriate times. Cheong reached out to a worldwide network of ham radio operators and amateur astronomers and found Jan van Muijlwijk, a sound technician near Groningen in the Netherlands with the ability to broadcast from the Dwingeloo radio telescope, a dish originally used in the 1950s. van Muijlwijk could only help on weekends.
On 10 June, Dwingeloo contacted INSPIRE-2 and uploaded the new commands, but couldn't detect UNSW-EC0 despite orienting in the — theoretically correct — location. INSPIRE-2 was up and running on the next orbit, so the procedure had worked, but the team couldn't find UNSW-EC0. The next theory was that NORAD had mislabeled EC0, or 'Echo' as the engineers had begun to call it, on its launch. Nanjing University's NJUST-1 and the University of Colorado's Challenger were deployed simultaneously with UNSW-EC0, so the team took a punt and pointed the Dwingeloo dish at those — and found a weak signal that was nonetheless clearly from EC0.
After that, it was a matter of firing off the software update, and on the next orbital pass the UNSW-EC0 satellite was fully recharged, up and running and in the correct orientation. Mission successful. Both satellites now in contact with Earth will go through testing before being commissioned and starting to collect thermosphere research data, helping scientists understand an area of low orbit previously barely known about before now. The ACSER team is keen to help find the SuSAT cubesat, too, if it's still in operable condition.
Aboutanios is understandably elated: "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."