A nominal space weather monitoring system requires assets in deep space at the L1 and L5 Lagrange points or similar. These satellites are needed to provide real-time information about the state of the Sun and the solar wind. The measurement requirements are defined by the ‘end user’, which is, for example, NOAA or the Met Office. Whilst these requirements – the types of measurement and their quality (resolution, cadence etc.) – are similar to those placed by a pure heliophysics science mission, there are important differences.

In this invited contribution, we consider these issues in the specific context of an operational L5 space weather mission. We describe the operational measurement requirements and examine how they are similar to and different from those one might expect on a science-oriented mission. We then outline some open important science questions that can be addressed with such observations, and describe how operational data could also be used in conjunction with other satellites to enable a deeper scientific understanding of the physics that underpins space weather.