 | |
| Names | Formerly known asLagrange |
|---|---|
| Mission type | Space Weather nowcast, forecast |
| Operator | European Space Agency |
| COSPAR ID | TBD |
| SATCATno. | TBD |
| Website | https://www.esa.int/Space_Safety/Vigil |
| Mission duration | Cruise phase: 3 years Operations: 4.5 yearsExtension: 5 years Designed operational life span: 20+ years |
| Spacecraft properties | |
| Launch mass | 2,500 kg (limit) |
| Dry mass | ~1,100 kg |
| Payload mass | ~150 kg (before system margins) |
| Power | Spacecraft ~1000 W; Payload ~200 W |
| Start of mission | |
| Launch date | Q3 2031 (planned)[1] |
| Rocket | Ariane 62 |
| Launch site | Guiana Space Centre |
| Contractor | Arianespace |
| Orbital parameters | |
| Reference system | Sun-Earth L5 |
| Regime | Lissajous orbit |
← NEOMIR | |
Vigil,[2] formerly known asLagrange,[3] is a futurespace weather mission under development by theEuropean Space Agency (ESA). The mission will provide the ESA Space Weather Office with instruments able to monitor theSun, itssolar corona, andinterplanetary medium between the Sun and Earth, to provide early warnings of increasedsolar activity, to identify and mitigate potential threats to society and infrastructure, as well as to allow 4 to 5 days space weather forecasts.[4] To this purpose theVigil mission will place for the first time a spacecraft at Sun-EarthLagrange point 5 (L5) from where it would get a 'side' view of the Sun, observing regions of solar activity on the solar surface before they turn and face Earth.[5][6]
Monitoring space weather includes events such assolar flares,coronal mass ejections,geomagnetic storms,solar proton events, etc.[7] The Sun-Earth L5 location provides opportunities for space weather forecasting by monitoring the Sun beyond the Eastern solar limb not visible from Earth, thus increasing the forecast lead time of potentially hazardous solar phenomena including solar flares, fast solar wind streams.[8]
TheVigil mission will improve the assessment ofCoronal Mass Ejection (CME) motion and density, speed/energy, arrival time and impact on Earth to support protection of the critical infrastructure on ground and in space. The mission will also perform in-situ observations of thesolar wind bulk velocity, density, and temperature as well as theInterplanetary magnetic field (IMF) at L5, to provide enhanced detection and forecasting of high-speedsolar wind streams andcorotating interaction regions.[citation needed]
Vigil mission objectives can be grouped in two main categories:
As part of the Space Situational Awareness Programme (SSA),[9] ESA initiated in 2015 the assessment of two missions to enhance space weather monitoring. These missions were initially meant to utilize the positioning of satellites at the Sun-Earth Lagrangian L1 and L5 points. Eventually, in the frame of the cooperation on space-based space weather observations between theEuropean Space Agency (ESA) and the United StatesNational Oceanic and Atmospheric Administration (NOAA) National Environmental Satellite Data and Information Service (NESDIS) the following was agreed[citation needed]:
In the scope of this agreement the two agencies will share data and provide each other with instruments to be embarked on the respective platforms.[citation needed]
Then a new opportunity arose:ISRO had plans to start a new solar observatory in low earth orbit. ESA convinced ISRO to expand the mission to a larger satellite bus, more instruments, and operate it at Lagrange Point L1. The Indian Space agency hesitated because it never had operated a spacecraft at L1 before. ESA supported the necessary software upgrade with trajectories of real ESA spacecrafts. The Indian spacecraft operating system showed very similar results and was then certified to operate spacecrafts at the Lagrange Points. In exchange for sharing data, ESA providesESTRACK service forAditya-L1, which started in 2023.[citation needed][4]
The space segment of theVigil mission completed the first part of Preliminary Definition (Phase B1)[10] in June 2022. On 21 November 2022, ESA issued a Request for Quotation toAirbus Defence and Space Ltd. for the design, development and verification (Phase B2, C and D) of theVigil Space Segment.[11] The Phase B2 activities started in April 2024, with the Preliminary Design Review planned for Q1 2026 and the Critical Design Review in Q1 2028.[citation needed]
In October 2025, ESA and the South KoreanKASA signed a joint statement of intent about potential future sharing of data fromVigil and the KASA's upcoming solar probe mission to the Sun-EarthLagrange point L4.[12]
ESOC in Darmstadt will be Missions Operation Centre. The development of the Ground Segment, including the Mission Operation Centre and Payload Data Centre, will start in 2027 (TBC), although a series of preparatory activities are currently on going.[citation needed]
Vigil is scheduled to be launched in 2031,[1] followed by 3 years of cruise to L5. The mission aims to start quasi-nominal operation as soon as the spacecraft has reached the mid course point on its way to L5 (30deg separation from Earth with respect to Sun). Nominally from L5 for 4.5 years, with a possibility of extension up to 5 additional years.[citation needed] The robust design is for a lifespan of more than 20 year. The orbit around L5 is stable and can be maintained for decades with no or very little fuel consumption. The expectation is that it can get a similar lifespan asSOHO.
The launcher service is baselined asAriane 62 byArianespace from theGuiana Space Centre. The launcher will be in dual-launch configuration for injection in GTO. The spacecraft will be launched as secondary passenger with a commercial customer bound for geostationary orbit in a dual-launch with Ariane 6.4. This transfer option makes use of the Sun-Earth L1/L2 connection and theWeak Stability Boundary effects near L2 to reach L5.[citation needed]
After release of the spacecraft into GTO, it will perform a series of 3 Apogee Raising Manoeuvres (ARM) to make its way towards L1 within a period of 14 days, planned to minimise the transitions through the Van Allen belts. From L1 the spacecraft will be placed on a zero to low-cost transfer trajectory towards L2 from which it will then leave towards L5. Deep Space Manoeuvres (DSM), preceded and followed by correction manoeuvres, will be executed as needed.[citation needed]
When the spacecraft reaches L5, a braking manoeuvre to insert the spacecraft into the final orbit will be executed. Different options are investigated, resulting in a split of such manoeuvre in two burns. The cruise to L5 can take up to 3 years. To increase the use of theVigil spacecraft, the mission will enter in a pre-operational phase once the halfway through the journey L5.[citation needed]
Alternatives include the use of Ariane 62 for direct injection in L5,[citation needed] Ariane 64[13] orFalcon 9 provided bySpaceX.[14]
The Platform supplies all service-related functions required to support the proper operation and data collection of theVigil Payload Suite. The key feature of spacecraft concept for an operational mission likeVigil is a robust avionics architecture able to remain operational during the most extreme space weather events seen in the last hundred years. TheFailure Detection Isolation and Recover (FDIR) will be designed to enhance the autonomy of the spacecraft, thus reducing the risk of service interruption requiring ground intervention.[citation needed]
The Mission Data downlink is via X-band at an average data rate of ~1 Mbit/s (about 86 gigabits per day) with 24/7 coverage provided byESTRACK supplemented by additional commercial stations.[citation needed]
The mass at launch is projected close to 2500 kg. To reach SEL5 the proposed design will rely on a bi-propellantChemical Propulsion System equipped with a 450 N main engine.[citation needed]
The payload suite will include: 3remote sensing instruments and 2in-situ instruments. In the frame of the inter-agency cooperation between ESA andNASA,Vigil will offer the possibility to accommodate an additional NASA instrument of opportunity (NIO).[15]
The remote sensing instruments will allow to estimate size, mass, speed, and direction ofCMEs.
In-situ instruments can be used to monitor the Stream Interaction Regions (SIR)[17] and Co-rotating Interaction Regions (CIR) up to 4–5 days in advance before their arrival at Earth.
The Joint EUV coronal Diagnostic Investigation (JEDI) instrument, will be provided byNASA to be hosted on theVigil spacecraft.[18][19] The JEDI scientific objectives can complement those of theVigil mission, but it is not considered essential for its success.[citation needed]
The Ground Segment, consists of:[citation needed]
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