Smaller and less expensive satellites may soon orbit much closer to Earth, improving the quality of images they send back. The University of Manchester is heading up the project to develop remote sensing satellites that can operate at 200-450 kilometers above the Earth’s surface. An artist’s impression of the Discoverer satellite. Courtesy of the University of Manchester/A Macario Rojas. Remote sensing satellites currently operate at about 500-800 kilometers above the Earth, above the residual atmosphere that exists at lower altitudes. Peter Roberts, scientific coordinator for the project, said that observations of the ground also take place over this range, limiting resolution and often requiring large telescopes to be used. “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,” said Roberts. “But there are also many technical challenges which until now have been too great to overcome. This research tackles the problem on a number of fronts.” One issue is that the atmosphere is denser nearer to Earth. This means that drag on the satellites needs to be minimized and countered. To do this, the team will develop advanced materials and test them in a new wind tunnel that mimics the composition, density and speed of the atmosphere as seen by a satellite at these altitudes. This will allow the team to test how materials interact with individual atoms of oxygen and other elements in the atmosphere at speeds of up to 8 kilometers per second. The ultimate aim is to be able to use these materials to streamline the satellites. They will also test the materials on a real satellite launched into these lower orbits. The satellite will demonstrate how the atmospheric flow can be used to control the orientation of the satellite, much like an aircraft does at lower altitudes. In addition, the team will develop experimental electric propulsion systems which use the residual atmosphere as propellant. This approach has the potential to keep the satellites in orbit indefinitely despite the drag acting upon them. However, it also means that the satellites will re-enter quickly when they've reached the end of their mission avoiding the space debris problems experienced at higher altitudes. All of these technological developments will be worked into new engineering and business models identifying what future very-low-Earth-orbit remote sensing satellites would look like and how they would operate. The project will also map out the path for future exploitation of the developed concepts. Partners in the research are The University of Manchester, Elecnor Deimos Satellite Systems, GomSpace AS, University of Stuttgart, Universitat Politecnica de Catalunya, University College London, The TechToybox, EuroConsult and Concentris Research Management. A grant from the European Union’s Horizon 2020 fund will allow the research team to design and develop this new technology.