Case study

SMILE (Solar wind Magnetosphere Ionosphere Link Explorer)

SMILE will use a new technique combining innovative X-ray and ultra-violet instrumentation to provide global imaging of the Earth’s magnetosphere for the first time and investigate its dynamic response to the impact of solar wind.

Coronal mass ejection reaching Earth

Credit: ESA


ESA-CAS (European Space Agency and Chinese Academy of Sciences) collaborative Small class mission to study the interaction between the Earth’s magnetosphere and solar wind. The magnetosphere is a vast region around our planet that protects us from solar wind and cosmic particle radiation. The Earth’s magnetosphere is the strongest of all the rocky planets in our solar system and its protective role is thought to have played a key role in the Earth’s habitability.

Multidisciplinary science return: Planetary (Earth and beyond), solar physics, space plasma and astrophysical communities are all served by the science explored by SMILE.

Downstream applications in validating space weather models – space weather being recognised on the UK government’s National Risk Register as a key disruptive threat to UK national technological infrastructure.

Observational approach will combine soft X-ray imaging of the Earth’s magnetic boundaries and magnetospheric cusps with simultaneous UV imaging of the Northern aurora, while self-sufficiently measuring solar wind conditions. For the first time SMILE will trace and link the processes of solar wind injection in the magnetosphere with those acting on the charged particles precipitating into the cusps and eventually the aurora, measuring the recently discovered solar wind charge exchange.

UK-China academic proposal was jointly selected by ESA and CAS in 2015.


  • Soft X-Ray Imager – UK led
  • Light Ion Analyser & Magnetometer – China
  • Ultra Violet Imager – Canada

ESA is providing Payload Module and Launch with China providing the spacecraft platform.

Mission launch date is due late 2023.

UK funding and roles

Initial two year investment of £3M, with plans to extend support for full mission delivery, subject to further review.

Overall mission science lead: Prof Graziella Branduardi-Raymont, UCL-MSSL, Mission Co-PI. Leads mission level science development alongside Chinese counterpart Prof Chi Wang (Director of National Space Science Center, Chinese Academy of Sciences).

  • Leicester build overall optics using innovative ‘lobster-eye’ micropore technology
  • MSSL provide Front end electronics
  • Hardware and design contributions from range of international partners incl. Spain, Norway, Switzerland, US
  • Prof Andrew Holland, Open University, testing and characterising SXI detectors
  • SXI CCD (Charged Couple Device) detectors provided by Teledyne e2v (Chelmsford, UK) under separate contract to ESA

Thales Alenia Space UK one of three companies in parallel study phase to provide the SMILE spacecraft’s Payload Module under contract to ESA – ESA down-selection in March/April 2019.

MSSL Co-Investigator support role on Chinese led Light Ion Analyser instrument.

Current status & next steps

  • SXI breadboard optic testing complete
  • All instrument and mission level System Requirements Reviews complete
  • Formal ESA mission adoption scheduled for March 2019
  • Preparation underway for next major instrument milestone, Preliminary Design Review in July 2019
  • SXI Critical Design Review September 2020
  • SXI flight instrument delivery January 2022
  • Launch date 2023

UK benefits & impact

Thales Alenia Space UK (TAS-UK) currently in competitive study phase with two non-UK companies for SMILE Payload Module (PLM). If successful the estimated contract value is £10M-£15M.

SMILE PLM activity is key component of TAS-UK growth strategy, the current study activity helps to grow its capability towards being a full (prime) spacecraft developer, and build its relationship with ESA Science Programme.

Teledyne e2v are supplying the SXI CCD detector devices under an approx. £1.5M contract to ESA. Joint academic-industry knowledge exchange with Open University on the CCD development programme will improve space radiation hardiness of the devices, maintaining this key UK technology for commercial sales and export opportunities.

SMILE data will validate and improve existing space weather models, the academic UK team has already carried out preliminary work with the Met Office Space Weather Operations Centre in view of supporting their work with SMILE data.

SMILE data will be of relevance and importance for the entire solar, heliospheric, magnetospheric and planetary science communities – disciplines in which the UK is world leading.

Leadership of the SXI enables UK teams to shape the scope and format of data in line with their requirements and areas of expertise. Detailed instrument knowledge will aid interpretation and subsequent long term scientific exploitation of the data.

Published 10 April 2019