Taking money out of an ATM in another part of the world is something you take for granted. It’s the same for GPS in your car and daily weather forecasts.
Yet the more we rely on satellite technology for these services, the more we are likely to be affected when they fail. The main issue for satellite technology is space junk.
“Humans have only been sending rockets and objects into space for 57 years, but before we know it our planet will be surrounded by an impenetrable layer of junk and rubbish, and each piece of rubbish – no matter how small – poses a threat to satellites,” says Professor Kefei Zhang , Director of RMIT’s SPACE Research Centre.
Space junk or space debris is the collection of defunct objects in orbit around the Earth. It includes spent rocket stages, old satellites, things let go by astronauts on their space walks, fuel cells, and fragments from disintegration, erosion and collisions.
Since 2009, about 19,000 pieces of debris larger than 5 centimetres were tracked, with 300,000 pieces larger than 1cm estimated to exist below 2,000 kilometres.
For comparison, the International Space Station orbits in the 300 to 400km range and the 2007 antisat test occurred from 800 to 900km.
“Each collision results in what is known as Kessler syndrome – where more junk and debris is created and it has a cascading effect,” says Zhang.
“Satellites cost around $700 million each, and we rely on them for everything from GPS to weather prediction, from TV to effective use of emergency services, but even a 1cm piece of debris can cause major damage and disruption to services.”
Zhang and his team of researchers are working with key partners Electro Optic Systems and the ANU on this project. Other parties involved include Optus, Lockheed Martin Australia and the National Institute of Information and Communications Technology, Japan.
Zhang continues: “This is a huge issue – space is now polluted with more than a million pieces of debris.
“Billions of dollars have been spent on the International Space Station and in 2012-13 alone there were four emergency evacuations because of unpredicted debris that required the ISS crew to retreat temporarily to their Soyuz spacecraft.”
A collision between US and Russian satellites in 2009 accelerated the need for solutions to be found to the problem, when it resulted in 3000 new pieces of space debris.
RMIT’s role in the $20 million, five-year international research project is to develop new tools to improve the accuracy and reliability of predictions about the behaviour of space debris in relation to the orbit of satellites.
This includes a new model for predicting how the debris will be affected by space weather, atmospheric drag and the Earth’s gravitational field.
RMIT’s SPACE – Satellite Positioning for Atmosphere, Climate and Environment – Research Centre is also investigating ways to improve severe weather prediction and potentially reduce the impact of natural disasters.
The centre has expertise in space tracking, satellite positioning and navigation, GPS meteorology, atmospheric studies, geodesy and ubiquitous positioning and tracking.
“We are a unique group working on ground-breaking research into platform technologies for space, atmosphere and climate applications.
“These are big, expensive and very challenging problems, but it’s great that Australia has taken the lead on these critical issues,” Zhang says.
Watch this space.
Story: Deborah Sippitts
Photo: Damien Sullivan
This story was first published in RMIT's Making Connections magazine.