ESA Vigil Mission - Space Weather Monitoring from L5

The Vigil Mission shall position a satellite at the 5th Lagrangian point (L5) with the objective to perform continuous observations of the Sun and the space between the Earth and the Sun to provide measurement data for space weather nowcasting and forecasting and for event-based warnings and alerts when solar events take place. The observations from L5 will complement space weather monitoring from Sun-Earth line and enable more accurate space weather impact predictions and early warnings of potentially hazardous solar weather conditions emerging. ESA is cooperating in space weather monitoring with the US (NOAA and NASA) who are planning to continue maintaining operational space weather monitoring on the Sun-Earth line by missions to the 1st Lagrangian point (L1) and by instruments onboard satellites orbiting the Earth.

The field of view from L5 allows monitoring of the onset of Coronal Mass Ejections (CMEs) with a coronagraph from a different angle than coronagraphy from the Sun-Earth line. Combination of the observations from two directions is foreseen to provide better estimates of the CME direction and speed, and to allow detection of faint “stealth” CMEs and CMEs that are ejected rapidly one after another. Vigil mission will also be able to monitor the entire space between Sun and Earth with a heliospheric imager allowing mid-course tracking of solar wind features including CMEs as they travel towards Earth. Vigil mission will enable observation of the solar disc several days before it becomes visible from the Earth. Longer monitoring of the active regions and their flaring is expected to make statistical flare forecasting more accurate. Vigil observations also prevent situations where strong flaring can be detected behind the solar horizon but without means to investigate the seriousness of the threat further. In-situ measurements in L5 will allow monitoring of high-speed solar wind streams several days in advance before they rotate towards the Earth. Magnetograph observations from L5 will provide fresh solar magnetic field data for numerical solar wind models used in CME propagation estimation and enable more precise predictions of the CME arrival times on Earth. Magnetograph data is also expected to improve the solar flare and CME onset forecasting accuracy.

As the baseline payload the Vigil spacecraft will carry 5 instruments, with 3 instruments dedicated to remote sensing of the Sun and the interplanetary space between the Sun and the Earth, and 2 instruments in-situ measuring the interplanetary magnetic field (IMF) and the solar wind characteristics at the L5 position. In addition, Vigil will carry a NASA targeted Instrument of Opportunity (NIO) as a hosted payload. In June 2024 NASA has announced that the selected instrument for the Vigil mission will be the “Joint EUV coronal Diagnostic Investigation (JEDI)”.

The aim of the Vigil mission is to demonstrate the benefits from space weather observations away from the Sun-Earth line for operational applications. For that purpose, the mission is designed to carry out observations at all times including severe space weather events and to provide data about the current space weather conditions in a 24/7 operational mode. The data for operational space weather applications shall be delivered to the users with low latency. In addition Vigil mission will support “bonus science” by making all measurement data available for research purposes through the data archive in the ESA Space Weather Data System.

This presentation will provide the status of the Vigil mission implementation. The presentation will discuss the mission objectives, planned data products and the utilization of the data both in operational applications and in scientific research.