The various demands on funding agencies make it difficult to sustain the level of expenditure required to provide the broad range of space astronomy missions that the research community would like to have available. Multi-billion pound/dollar observatories such Chandra, XMM-Newton and HST have been enormously successful, but JWST has been delayed and plans for an equivalent large X-ray mission seem to be on-hold. Furthermore, the medium size ESA and NASA missions provide only a small number of opportunities over the next decade. Much exciting and important science, by default, will not be done. If satellite mission costs could be reduced significantly, by a factor of 5-10, we would open up a new parameter space of opportunity that is not currently offered by any agency. Significant improvement in instrument technology coupled with simplification of optical systems and the development of efficient, high performance small satellite platforms and ground systems has led to the prospect of the development of some low-cost opportunities. In this paper, we outline one such possible mission, based on a successful sounding rocket-borne payload. This comprises a high throughput normal incidence extreme ultraviolet spectrometer, with the design adapted for accommodation on the SSTL 300 platform. We make use of a segmented diffraction grating to provide an overall wavelength coverage from ~170-260Å by tuning the multi-layers of the individual elements to different, overlapping ranges. We outline the capability and science goals of the mission, and how they influence the design and operation of the satellite platform. We conclude with a discussion of how missions of this type operating both as constellations and as formation flying sparse apertures, could offer a scientifically viable alternative to monolothic 'great observatory' missions in the future.