ARRAKIHS, the first mission of the European Space Agency (ESA) Science Programme led by Spain through the Ministry of Science, Innovation and Universities (MICIU) and the Spanish Space Agency (AEE), has officially entered its development phase ahead of its planned launch in 2030.

ARRAKIHS has now formally become the F2 mission of ESA’s Science Programme, completing a process that began with its selection in 2022. This decision marks a new milestone for the first ESA science mission led from Spain and strengthens the country’s position at the forefront of European space exploration.

“With ARRAKIHS, Spain is placing itself at the forefront of European space exploration,” said Diana Morant, Minister of Science, Innovation and Universities.

“It is a mission that generates knowledge, strengthens our industrial ecosystem, attracts talent, and showcases our country’s capabilities internationally,” added Minister Morant, who also highlighted that “the advances this mission will bring to understanding how galaxies form and the nature of dark matter will bear the hallmark of Spanish science.”

F-class (Fast) missions are a category within ESA’s Science Programme designed to be developed on shorter timescales and with lower costs than the Agency’s larger missions, enabling a more agile response to emerging scientific challenges. ARRAKIHS is the second mission selected within this programme line and the first to be led by Spain.

Adoption is the formal decision through which ESA authorizes a mission to move from the design phase into development and construction.

The decision was unanimously approved by the 23 ESA Member States gathered at the Science Programme Committee (SPC), taking place today and tomorrow in Tenerife under the chairmanship of Cecilia Hernández, Director of Programmes and Industry at the Spanish Space Agency.

Prior to adoption, ESA’s independent scientific committees and advisory bodies assessed the mission’s scientific objectives and technical feasibility. ARRAKIHS successfully completed all required conceptual and preliminary design phases, culminating in the successful Preliminary Design Review (PDR), which certified the mission’s maturity to proceed to detailed design, manufacturing, integration, and validation of both the satellite and its scientific instrument.

Revealing the Faint Universe

ARRAKIHS was selected by ESA in 2022 as a candidate to become the second F-class mission within its Science Programme. Since then, the mission has successfully completed all definition and preliminary design stages required by the Agency, demonstrating its scientific, technical, and programmatic feasibility.

The mission was conceived to address one of the major open questions in modern astrophysics: how galaxies form and evolve within dark matter halos. To achieve this, it will observe with unprecedented sensitivity the diffuse, low surface brightness stellar halos surrounding galaxies similar to the Milky Way.

ARRAKIHS will open a new window onto the so-called low surface brightness Universe, enabling the study of structures that have remained largely hidden until now and providing new insights into dark matter, galaxy mergers, and galaxy evolution.

IFAE Contribution

IFAE participates in ARRAKIHS as the institution responsible for the characterization and calibration of the H2RG infrared detectors that will form part of the mission’s scientific instrument. This contribution builds on extensive experience accumulated through the development, characterization, and operation of detectors for space and astronomical projects such as PAU, ASTEROID, ATHENA, and Euclid.

The institute also contributes its expertise in the design, construction, and operation of advanced cryogenic infrastructures developed throughout these projects, as well as specialized optical equipment required to validate and calibrate the detectors under representative operating conditions.

IFAE’s activities within ARRAKIHS are led by Cristóbal Padilla together with Jorge Jiménez and Fernando Abárzuza.

From Concept to Mission

Since its selection by ESA in 2022, ARRAKIHS has successfully completed all the steps required to become a fully established mission within the European Science Programme. During this period, the international consortium completed the preliminary design of the satellite and its instruments, developed new cosmological simulations and galactic models, validated key technologies, and strengthened the mission’s scientific potential through increasingly deep observations of the low surface brightness Universe.

With its official adoption as the F2 mission, ARRAKIHS leaves the definition phase behind and enters the development and construction stage. The planned launch in 2030 will mark the beginning of a mission expected to transform our understanding of galaxy formation and the nature of dark matter, while further consolidating Spain’s scientific, technological, and industrial leadership in the European space sector.

The ARRAKIHS Mission

The ARRAKIHS science team is led by Rafael Guzmán, research professor at the Institute of Physics of Cantabria (IFCA), a joint center of the Spanish National Research Council (CSIC) and the University of Cantabria (UC).

The ARRAKIHS mission (Analysis of Resolved Remnants of Accreted galaxies as a Key Instrument for Halo Surveys) was proposed to ESA’s F Missions (Fast Mission Opportunities) programme and is being developed by an international consortium involving research institutions from Spain, Switzerland, the United Kingdom, Belgium, Sweden, Austria, and the United States, in response to ESA’s call for proposals published in December 2021.

In July, the mission received support from the then Ministry of Science and Innovation through its inclusion in ESA’s PRODEX programme, managed in Spain by the Centre for the Development of Industrial Technology (CDTI).

An Astronomical Milestone

For the mission, the Spanish company Satlantis has designed and developed a visible and infrared binocular camera that will obtain images of one hundred galaxies similar to the Milky Way, reaching surface brightness levels 5 to 100 times deeper than the best images obtained from ground-based observatories.

The depth, resolution, and wide field of view provided by ARRAKIHS will represent a major astronomical milestone and will deliver key information for advancing our understanding of dark matter in the Universe.