ESA officially adopts ARRAKIHS as F2 Mission: Europe leads the exploration of the low surface-brightness Universe
The mission enters its critical design phase ahead of a 2030 launch.
ARRAKIHS simulation of faint halo features around a spiral galaxy like the Milky Way. Credit: Alex Camazón (IEEC) / AMC
By
Ana Isabel Silva Martins
PublishedJune 11, 2026
The European Space Agency (ESA) has officially adopted ARRAKIHS as the second FAST-class (F2) science mission, confirming the target launch year of 2030. ESA’s decision begins the mission’s critical design and construction phase, during which the spacecraft and its scientific instruments will be built, integrated and space-qualified.
Revealing the faint Universe
Selected by the ESA in 2022, ARRAKIHS (Analysis of Resolved Remnants of Accreted galaxies as a Key Instrument for Halo Surveys) is designed to answer a central question in modern cosmology: how do galaxies assemble their mass over time within the Standard Model of Cosmology?
The low surface-brightness stellar halos around galaxies like the Milky Way act as archaeological records. They contain tidal stellar streams and dwarf satellite galaxies left by past mergers and accretion events. Those structures are often orders of magnitude fainter than the main galaxy and hard to detect with existing surveys.
“Many of these structures are extremely faint and difficult to study systematically with existing observations,” explains Rebekka Coles-Bieri (UZH), the mission’s Science Coordinator.
ARRAKIHS will let us quantify how common different accretion events are and link them to galaxy mass, environment and dark-matter halo properties.
Members of the ARRAKIHS instrument team working on the scientific payload. Credit: Satlantis/IDR/UPM
An international collaboration — and Norway’s strong role
ARRAKIHS is developed by ESA together with the ARRAKIHS Mission Consortium (AMC), led by Prof. Rafael Guzmán (IFCA, CSIC–UC). The consortium comprises more than 250 scientists and engineers from seven ESA member states led by Spain (Austria, Belgium, Norway, Portugal, Sweden and Switzerland), plus contributions from institutions and industry in the UK, France, Denmark, the Netherlands, the USA, Taiwan and Thailand.
Norway and the University of Oslo (Institute of Theoretical Astrophysics, ITA) are actively involved in ARRAKIHS. Sijing Shen, Professor at ITA, is the coordinator of the Norwegian participation and a member of the mission Core Team. She also co-leads the Cosmological Models (COS) Working Group, producing state-of-the-art simulations tailored for the low surface brightness Universe. Martin Wiesmann and Stein Vidar Hagfors Haugan, Senior Engineers at ITA, contribute to the Instrument Operations and Science Data Center (IOSDC) via Norwegian Space Agency funding; Martin is Deputy Coordinator of the IOSDC. The Norwegian company Integrated Detector Electronics AS, IDEAS, will design and produce the NIR (near-infrared) interface board — a significant contract and recognition for the company. UiO team members Martina D'Angelo (Adviser) and Sijing Shen are also working on an EU outreach proposal (AURA) that pairs outreach activities with Norwegian artists and high-school students.
“ARRAKIHS will revolutionise our understanding of galaxy formation and evolution. At ITA, we are thrilled to bring our cutting-edge data processing, high-performance computing and deep scientific exploration to the forefront of ESA's quest to reveal the faint Universe. We are also happy that Norwegian industry, through IDEAS, can supply such a major contribution as the NIR interface board.” - Professor Sijing Shen, Coordinator of the Norwegian Participation in ARRAKIHS.
Family photo at the 5th ARRAKIHS Consortium Meeting. Credits: AMC
From concept to adopted mission
Over recent years, the AMC has turned an ambitious scientific concept into an ESA-adopted mission. Achievements so far include:
New high-resolution cosmological simulations and realistic galaxy models used to predict faint halo signatures.
Design of key instrument subsystems and prototype hardware.
Development of ground-based software and data systems for processing deep, low-surface-brightness observations.
Operation of a ground demonstrator camera at the Javalambre Astrophysical Observatory and acquisition of deep observations that strengthen the mission’s science case.
With ESA adoption, ARRAKIHS now moves into spacecraft and instrument construction and the final development of the science data pipeline ahead of launch in 2030.
Quick facts
ARRAKIHS will obtain images of at least 80 Milky Way-like galaxies in the Local Universe.
Each galaxy will be observed for a total of 150 hours, combining 900 exposures, each with a 10-minute integration time.
The spacecraft orbits the Earth every 100 minutes.
Notes for editors
ARRAKIHS: Analysis of Resolved Remnants of Accreted galaxies as a Key Instrument for Halo Surveys.
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