Engineers at the University of Manchester are leading a European effort to develop remote-sensing satellites that could fly in far lower orbits than any existing technology.
Such spacecraft could provide better resolution images and would be easier to bring back down to Earth at the end of their lives, thereby reducing the chances of them contributing to the growing problem of space debris.
Widely used for environmental and defence applications, remote sensing satellites currently operate at about 500-800km above the Earth. The Manchester-led team, which is working with a €5.7m grant from the EU’s Horizon 2020 fund, hopes to develop satellites able to operate at just 200-450 km above the Earth’s surface – lower than the international space station.
Dr Peter Roberts, the project’s Scientific Coordinator, said: “If we are able to get satellites closer to Earth then we can get the same data using smaller telescopes, or smaller and less powerful radar systems, all of which reduces the satellite mass and cost.”
One of the key areas of the project will be developing a solution to the additional atmospheric drag that will be encountered at these lower altitudes.
To this end, the team will develop advanced materials and test them in a new ‘wind tunnel’ which mimics the density of the atmosphere and will allow them to test how materials interact with individual atoms of oxygen and other elements in the atmosphere at speeds of up to 8km per second.
The group will also test the materials on a real satellite launched into these lower orbits. The satellite will also demonstrate how the atmospheric flow can be used to control its orientation, much like an aircraft does at lower altitudes.
In addition, the team will develop experimental electric propulsion systems that use the residual atmosphere as propellant. This approach has the potential to keep the satellites in orbit indefinitely, despite the drag acting upon them.