23 Apr 2018



The primary goal of the Lagrange mission is to enable improved forecasts of the arrival of space weather phenomena at Earth, through real-time monitoring of the Sun and solar wind from the unique Lagrange L5 vantage point. 


​​​​​​​Artist impression of the future spacecraft

Credit: ESA

​The term “Space Weather" describes the potentially damaging effect of the Sun on human technological systems and health. Increasing global awareness of the potential threat of severe space weather at Earth, caused, in particular, by the arrival of coronal mass ejections, CMEs, has inspired ESA to develop a space weather-monitoring mission to the L5 point – located 60 degrees behind the Earth in its orbit – under the auspices of its Space Safety programme. In combination with a complimentary US space mission, located a million miles sunward of the Earth, the Lagrange mission will form a key element of an early warning system for severe space weather.

RAL Space Involvement   

RAL Space leads the four-spacecraft remote-sensing instrument package, as well as leading two of the instruments therein, the coronagraph and heliospheric imager.

Solar Physics

Main Objectives 

The Lagrange L5 mission will help improve space weather services via:

  • improved assessment of developing activity on the Sun
  • improved assessment of coronal mass ejection motion and density
  • measurement of the background solar wind prior to the Earthward rotation of its source
  • improved input to space weather modelling endeavours
  • improved understanding of the science behind space weather to inform future space weather mitigation strategies

The Lagrange payload comprises two instrument suites, the remote-sensing instrument package that includes a solar magnetograph, an Extreme Ultraviolet Imager, a coronagraph, and a heliospheric imager, alongside an in-situ package composed of an X-ray flux monitor, a solar wind analyser, a magnetometer, a medium energy spectrometer, and a radiation monitor.

Launch Date   


​ESA; Mullard Space Science Laboratory, UK - leading in-situ instrument package; Airbus Defence and Space, UK - leading system study.​

Further Project Information 
ESA - Lagrange mission​