OLFAR: the orbiting low frequency array, how a cube sat swarm becomes a novel radio astronomy instrument in space

To study the physical processes in the Universe, observations are done at various wavelengths, from Gamma rays to optical and radio frequencies. At this moment research at low frequencies is one of the major topics in radio astronomy. Several Earth-based radio telescopes are being built and will be operational very soon (for instance the LOFAR radio telescope in the Netherlands [1, 2], which was opened June 12th by Queen Beatrix of the Netherlands), opening a new observational window. Below 50 MHz there are serious limitations when observing from Earth. In this article we introduce the OLFAR (Orbiting Low Frequency Array) project, which is aimed at exploring these ultra-long wavelengths, by building an antenna array in space using a swarm of very small satellites (cube sats). The project will demonstrate that swarms are not just science fiction, but can be used to do real science. Also, the OLFAR project will show that students (both PhD and MSc) can play an important role in the design and implementation of a serious scientific space-borne instrument.