The European Space Agency has given the green light to two new small satellites that will peer through forest canopies and track invisible waves rippling through the sky. One will measure biodiversity hidden beneath tree cover. The other will study how atmospheric gravity waves shape the upper atmosphere. Both are part of ESA's Scout program, which builds cheap, fast satellites to answer big scientific questions.
Hibidis: A hyperspectral eye on the forest floor
Hibidis, short for Hyperspectral Biodiversity Scout, carries a special imager that can see the same patch of Earth from three different angles. This trick lets it separate the leafy canopy above from the understorey below. By doing so, the satellite will assess Essential Biodiversity Variables, giving scientists a new way to monitor ecosystem health without setting foot on the ground. The prime contractor for Hibidis is SITAEL in Italy.
SOVA-S: Tracking gravity waves in the sky
SOVA-S will focus upward, not downward. It will investigate atmospheric gravity waves, which are not the same as gravitational waves from space. These are ripples in the air, often triggered by mountains, storms, or jet streams, that travel high into the thermosphere. SOVA-S aims to measure how these waves influence the upper atmosphere and the ionosphere, a region that affects radio communications and satellite navigation.
How the missions were chosen
ESA selected Hibidis and SOVA-S from four final competing concepts after a 10 month evaluation by the Earth Observation Programme Board. The Scout program itself is a relatively new part of ESA's FutureEO initiative. Unlike larger Earth Explorer missions, Scouts are designed to be agile and low cost. They embrace the New Space philosophy: move fast, use off the shelf technology or miniaturized instruments, and deliver results quickly. Simonetta Cheli, ESA's Director of Earth Observation Programmes, said the decision was not taken lightly and came only after stringent assessment.
Joining a growing fleet
Hibidis and SOVA-S will join three other Scout missions already in development or orbit. HydroGNSS launched in November 2025 to measure soil moisture, wetlands, and other hydrological variables. NanoMagSat is being built to study Earth's magnetic field and the Sun's influence on the atmosphere and ionosphere. Tango will monitor methane, carbon dioxide, and nitrogen dioxide emissions from large industrial sites. Together, these small satellites show that fast, cheap missions can still deliver serious science.
What this means for science
Hibidis will give ecologists a new tool to map forest biodiversity from space, especially in dense tropical forests where the understorey is hard to see. SOVA-S will help atmospheric scientists understand how energy moves through the upper atmosphere, which has practical implications for weather prediction and space weather. Both missions are expected to move quickly from selection to launch, continuing ESA's push for rapid, cost effective Earth observation.
