GAUDI: Global All-sky Ultraviolet Detection Instrument

(mini-F Mission Concept)

The Science 

Ultraviolet (UV) light carries the first, and the most important diagnostic signatures of explosions, magnetic flares and accretion episodes. However, current space-based UV observatories, due to their small fields of view (FoV), still deliver sparse revisits and few real-time triggers. 

The primary goal of GAUDI is to deliver multi-cadence (seconds to days), UV and optical photometry for the whole observable sky with a precision of 0.02 mag for sources brighter than AB≈16 mag in both UV and VIS. This dataset, expanding the 2 years lifetime of the mission, will provide critical information of transient and variable phenomena. Its enhanced cadence and wavelength coverage offers strong synergies with current and future large time-domain surveys, which are designed to obtain deeper photometry, albeit with much slower cadence.

The Mission

GAUDI is an 84 kg mini-satellite carrying eight identical wide-field telescopes (8°×8° FoV each), arranged in two orthogonal sets of four, each mounted behind an independent rotating siderostat mirror. GAUDI has 4 different photometric passbands (MUV=205-300 nm, F330W=300-370 nm, WIDE=500-840 nm and RED=670-840 nm). From a dawn-dusk Sun-Synchronous orbit (SSO, height~500 km), the spacecraft maintains inertial attitude while each telescope is observing a given field. The resulting light curves have simultaneous color-index measurements and sub-minute temporal resolution when observing a specific field, achieving complete sky coverage per telescope twice (once per great circle) every 1.5 days.

The Team

IEEC is the PI institution and will host the project office, including payload management and system engineering. The consortium comprises scientists expert from IEEC institutes: UB, UAB, UPC, ICE, with scientific support from other institutes in Spain (UAH:cosmic rays and UCM: UV), Portugal (UAVR: compression), Poland (UW: Ground-based follow-up), UK (IoA and UoW: Science alerts), Switzerland (UNIGE: Variability), Belgium (ROB: Variability), France (OCA: Solar system), and Ireland (TCD: Ground-based follow-up).

IEEC leads payload development, drawing from LISA, ARIEL, and PhotSat heritage, and is responsible for the siderostat, front-end electronics, ICU, and SW.

Open Cosmos (UK and Spain) are the satellite mission integrator providing the satellite platform and the mission operations centre.