Abstract Near Earth Objects (NEOs) are comets or asteroids that intersect or pass near to our planet posing a real and underestimated danger to mankind. While the probability of impact is low, the consequences of such an impact could be apocalyptic. Various programs are underway to discover these kilometer-sized objects from Earth. However, once targets of interest have been identified a fly-by or orbiting spacecraft is required to understand the objects’ mass, morphology and composition. Fly-past NEO missions represent the simplest interplanetary missions and need not be high cost. An ‘entry level’ mission has been conceptually designed able to deliver a 10 kg science ‘reference’ payload to NEO fly-by for a total mission cost (including launch and operations) of € 20 million (FY2003). This paper outlines the platform architecture, cost and cost drivers, and describes the key technology trades to be performed and the developments required to extend current Low Earth Orbit (LEO) technology to a deep space mission. It concludes by identifying the top-level trade-offs to be made in order to enhance the science return of the mission.