The first scientific space mission led by Spain is rehearsed from the mountains of Teruel: "We want to find out the role of dark matter"

Spain's first space mission led by the country is being tested in the Sierra de Teruel, with scientists aiming to uncover the role of dark matter in the formation of galaxies. The project, known as ARRAKIHS, involves a satellite designed to conduct what researchers call "galactic archaeology," studying the history of galaxies through observations of faint structures in the universe. The testing takes place at the Javalambre Astronomical Observatory, located atop the Pico del Buitre, a peak standing at 1,957 meters in the province of Teruel. This site has been chosen due to its exceptionally dark and clear skies, combined with favorable weather conditions, making it ideal for astronomical research. The observatory houses two professional telescopes used to create three-dimensional maps of the cosmos. In addition, a smaller replica of the instrument set to be launched into space is currently undergoing tests at the facility. According to Antonio Marín-Franch, who oversees operations at the observatory, the team works continuously throughout the year whenever conditions allow. "We observe whenever we can, all 365 days of the year. If it rains or there’s too much humidity, we can’t open the telescopes. But if we can observe for an hour one night, we do so," he explained. The mission aims to investigate how dark matter has influenced galaxy formation, addressing discrepancies between current cosmological models and observational data. ARRAKIHS will focus on detecting dwarf galaxies and tidal tails, remnants of galactic collisions, that are extremely dim and difficult to observe from Earth. These structures provide crucial insights into the nature of dark matter, which is believed to make up a significant portion of the universe's mass. Scientists want to determine whether these findings suggest adjustments to existing theories about dark matter or if previous observations lacked sufficient depth to detect such faint features. The satellite, once launched, will capture images of objects that shine 10,000 times less than the darkest sky visible from Earth. Achieving this goal presents a considerable challenge, as ground-based telescopes lack the sensitivity required to detect such faint signals. The mission, costing €320 million, includes €210 million contributed by the European Space Agency (ESA) and €110 million from the ARRAKIHS consortium. The approval of the mission marks a significant milestone for Spain's scientific and technological community. Marín-Franch emphasized the importance of the endeavor while touring the area around Arcos de las Salinas, a small village near the observatory. Accessing the observatory during winter poses logistical challenges, particularly due to potential snowfall and icy road conditions. Despite having well-equipped vehicles and protocols in place, including a dedicated snowplow acquired earlier this year, the risk of hazardous driving conditions remains. The journey to the observatory via a winding road takes about 20 minutes in summer, but the route becomes more treacherous in colder months. Previous winters have brought varying amounts of snow, with some years experiencing up to half a meter of accumulation. However, the primary concern is ice, which requires careful navigation even with specialized equipment. The initiative was originally proposed by Aragonese scientist Mariano Moles, who played a key role in establishing the astronomical installation managed by the Center for High Energy Physics. The ongoing work at Javalambre represents a major step forward in Spain's contribution to international space science, with the satellite slated for launch by the end of 2030 following approval from ESA during a meeting held in Tenerife last June.