This article titled "Australian '$1m lunch box' satellites to search thermosphere for answers" was written by Melissa Davey, for theguardian.com on Tuesday 9th August 2016 03.46 UTCResearchers hope to discover more about a little-understood understood layer of the Earth’s atmosphere, known as the thermosphere, when they launch 50 miniature satellites known as CubeSats from the International Space Station in January.
Three Australian-built miniature satellites are being contributed to the international project known as QB50, along with 47 other satellites from around the world. The CubeSats are about the size of a lunch box, weighing about 2kg, but cost $1m each.
The thermosphere was an important part of the atmosphere because it contained the ionosphere, ionised by solar radiation, and was where temperature regulation and the filtering of X-rays and ultraviolet radiation occurred, said the director of the Australian Centre for Space Engineering Research, Professor Andrew Dempster.
One of CubeSats, built by the University of New South Wales and named UNSW-Ec0, will carry an Ion Neutral Mass Spectrometer instrument to study the composition of the thermosphere.
“Random atoms striking the on board detector will be stripped of electrons, allowing the instrument to identify what elements they are,” a statement from the university said. “This level of detail, over such a long period of time, has never been undertaken before.”
The two other Australian CubeSats are named INSPIRE-2, built jointly by the University of Sydney, the University of NSW and the Australian National University and which will measure the temperature and density of the ionopshere, and SUSat, built by the University of Adelaide and the University of South Australia.
The CubeSats will all be launched to the space station in December by an Orbital ATK Antares rocket inside a Cygnus cargo freighter. They will be deployed in January, spiralling downwards from the station’s orbit in the thermosphere 380km above Earth.
Dr Elias Aboutanios, a UNSW-Ec0 project leader and senior lecturer in signal processing at the University’s Australian Centre for Space Engineering Research, said the satellites would then descend to about 150km over a period of between three and 12 months, where they would start to combust.
“The difficulty in studying the thermosphere in the past has been due to the fact whatever you send into it doesn’t stay there for long, because there is enough air in the thermosphere to make satellites drop down towards Earth quickly,” Aboutanios said.
“It also wasn’t cost effective, because the satellites each cost hundreds of millions of dollars.”
But advances in technology meant CubeSats had been developed which were lighter and, at $1m each, also much cheaper to build. The UNSW-Ec0 satellites had been four years in the making.
Aboutanios said while it was exciting it was to be a part of an international space project, there were nerves.
“There are things that can go wrong any time from now until they have been launched,” he said. “We still have to transport the satellites to the Netherlands and then to the US before we even get to the rocket ride itself, which in itself is nerve-wracking.
“But that is part of the excitement too. The greater the risk, the greater the excitement.”
Dempster said the thermosphere was vital to Earth-based communications and navigations systems. “AM radio waves are also refracted through the thermosphere, so the behaviour of the thermosphere affects how radio propagates, and it is also quite an important element of how satellite navigation works,” he said.
“Changes in the thermosphere can cause unwanted disturbances to satellite navigation, and you can get all sorts of errors. It is important to understand those disturbances.”
The launch will mark the first time Australian-made satellites have been sent into space since FedSat, a 58kg experimental micro-satellite launched from Japan’s Tanegashima Space Centre in 2002.
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