ESA approves two Scout missions Hibidis, SOVA-S

The European Space Agency approved two new Earth-observing Scout missions, Hibidis and SOVA-S, on May 20, expanding a small-satellite research line meant to move faster and more cheaply than the agency’s larger Earth Explorer missions. ESA said the two satellites were selected by its Earth Observation Programme Board after a 10-month evaluation of four finalist concepts. (esa.int) Hibidis will study biodiversity beneath forest canopies, while SOVA-S will examine atmospheric gravity waves and their effects on the upper atmosphere and thermosphere. The selections add to a Scout family that already includes HydroGNSS, ESA’s first mission in the series. ### Why did ESA pick these two missions now? ESA said on May 20 that Hibidis and SOVA-S emerged from a final group of four candidate Scout missions studied in detail after being narrowed from nine proposals in June 2025. (esa.int) The agency said the selection was formally approved by its Earth Observation Programme Board. The June 2025 shortlist also included NAIAD, focused on aquatic ecosystems and sediment and nutrient flows, and SIRIUS, an infrared imaging mission aimed at urban heat islands and heat-related health risks. ESA did not announce launch dates for the two winners in its May 20 release. ### What is Hibidis supposed to observe? (esa.int) Hibidis is designed to study understorey biodiversity and ecosystem functioning beneath forest canopies, ESA said. That puts its scientific focus on parts of forests that are difficult to monitor from space with more conventional observations. ESA’s earlier candidate-mission announcement identified Sitael in Italy as prime contractor for Hibidis. (esa.int) In that same June 2025 update, the agency described the mission as a hyperspectral concept intended to study understorey biodiversity and ecosystem functions. ### What does SOVA-S measure that other missions do not? (esa.int) SOVA-S will investigate atmospheric gravity waves and how they influence the upper atmosphere and thermosphere, according to ESA’s approval notice. Those waves are disturbances that move energy and momentum upward through the atmosphere and can affect conditions at higher altitudes. (esa.int) ESA said in June 2025 that OHB in Czechia was the prime contractor for the SOVA-S candidate mission. The agency’s latest release kept the scientific description broad and did not provide a spacecraft size, orbit, or launch provider. ### How do Scout missions differ from ESA’s larger Earth Explorer satellites? (esa.int) ESA describes Scout missions as a newer part of its Earth Observation FutureEO programme, intended to complement the Earth Explorer series rather than replace it. The agency says Scouts are built around small satellites, rapid development and lower cost, often by miniaturising existing technologies or testing new observing techniques. (esa.int) The June 2025 candidate announcement said each Scout mission must be delivered within three years from kick-off to launch and within a budget of €35 million. ESA says the format is meant to give industry and academia a more agile role in Earth-observation science. (esa.int) ### Where does HydroGNSS fit into this lineup? HydroGNSS is ESA’s first Scout mission and was launched on Nov. 28, 2025, aboard a SpaceX Falcon 9 rideshare mission from Vandenberg Space Force Base in California, ESA said. The two-satellite mission uses Global Navigation Satellite System reflectometry to measure variables including soil moisture, wetland inundation, freeze-thaw state and biomass. (esa.int) ESA says Scout missions are intended to add scientific value to current missions while testing new methods for observing Earth. With Hibidis and SOVA-S now approved, the next concrete milestones are mission development under the Scout framework; ESA’s May 20 release did not set launch dates or identify launch providers for either satellite. (esa.int 1) (esa.int 2) (esa.int 3)