Spain’s ARRAKIHS Mission To Be Launched in 2030 To Unlock the Secrets of Dark Matter in the Universe

The ARRAKIHS consortium has just passed the mission definition review of the project, marking a significant milestone towards fully completing the mission preparation. The ARRAKIHS satellite, to be launched in 2030, was selected by ESA to study the nature of dark matter.

Mysteries of Dark Matter

Some of the stars in the universe, especially those that belong to the first galaxies, bear witness to the early stages of the cosmos' formation. Although these stellar bodies appear extremely faint in the night sky, astronomers are convinced that these are also dominated by dark matter.

According to the current standard model of the universe governed by Einstein's theory, the cosmos comprises 68% dark energy and 27% dark matter, and only the remaining 5% is ordinary matter as we know and see it, such as planets and stars. Dark matter refers to a point detected gravitationally but is invisible. Experts need specific and dedicated observational techniques to identify and characterize these structures.

Theoretical studies suggest that the signature of the nature of dark matter is imprinted in the number of faint dwarf systems surrounding massive galaxies and the stellar streams in their halos. In the Milky Way galaxy, analogs are so faint in the night sky that they must be viewed from space, away from the Earth's atmosphere.

Exploring With ARRAKIHS Mission

The ARRAKIHS mission will look for these very faint structures, serving as a key to unlocking the secrets of dark matter. According to ARRAKIHS science component leader Pascale Jablonka, ESA calls it an F-mission, where "F" stands for 'fast.'

ARRAKIHS stands for Analysis of Resolved Remnants of Accreted galaxies as a Key Instrument for Halo Surveys. Inspired by a sci-fi planet in the novel Dune, this low-earth orbit satellite will attempt to unveil one of the darkest secrets of modern physics by studying the dark matter haloes of 75 different galaxies.

In 2022, ARRAKIHS was finally selected by ESA as its second F mission. During the past years, the European consortium members, led by Spain, have been working together to complete the mission study's initial phase, dubbed 'phase zero.' On September 27, the mission passed its first milestone, or the "mission design review," giving the consortium and the ESA study team the approval to move forward to the project's next phases.

Using efficient imaging technology, the research team will unveil and characterize stellar halo features. In this study, each galaxy will be monitored for 150 hours, and their halo structures will be decoded in every detail. The observations will be compared with different dark energy models and their predictions.

The study could bring together many research areas aside from dark matter, like galaxy evolution, image processing, and numerical simulations. Over the next two and a half years, the Mission Consortium and ESA will work together and collaborate with the other aerospace industry leaders for the next study phase.