Abstract DGP2026-105

QUakes On Venus - Airglow Detection using an Interplanetary small Satellite (QUO VADIS) is a small-satellite mission concept by Technische Universität Berlin (TUB) and DLR’s Institute of Space Research to investigate seismic activity on Venus by sensing venusquakes through airglow imaging and to demonstrate interplanetary advancements of TUB’s TUBiX20 satellite platform. The mission targets two primary science questions: (i) how geologically active Venus is today and (ii) how its surface and interior formed and evolved. These objectives are addressed by measuring the rate and spatial distribution of seismic events and by constraining interior structure through global observations of atmospheric wave signatures excited by surface quakes.

The science concept exploits the coupling of seismic surface waves into the Venusian atmosphere where quakes generate upward-propagating pressure disturbances that modulate airglow emission. The observables are the nightside O2​ airglow at 1.27 µm and the dayside CO2​ non-LTE emission at 4.3 µm, both previously observed by missions such as Venus Express. Expected modulation amplitudes are on the order of 1% for seismic events of magnitude Mw ≈ 6 at distances up to ~1000 km, where the dayside CO2 airglow signal is three times stronger than the nightside O2 airglow signal, imposing stringent requirements on radiometric sensitivity, temporal sampling and stray-light suppression. 

Trajectory and orbit design are addressed at a first-iteration level. An SEP-only transfer includes Earth escape (optionally supported by lunar gravity assists), interplanetary cruise, capture into a high Venus orbit, and SEP spiral-down to the nominal ~40,000 km science orbit. Current estimates for the combined transfer and spiral-down require ~1058 days and ~20.7 kg of xenon, with the spiral-down accounting for a large share of thrusting time and propellant use. Key system design drivers include high power demand from extended thrust arcs, radiation-hardened avionics to ensure mission lifetime and science return, and high data volume from continuous acquisition. The proposed orbiter uses a ~0.6 × 0.6 × 0.6 m cubic primary structure with deployable, steerable solar arrays. The system-level mass target is ~150 kg, with ~21 kg of propellant. Direct-to-Earth communications use a deep-space transceiver and a deployable ~60 cm antenna. Nominal science data generation is ~6 Gbit/day, driving the need for onboard prioritization, compression, and event-driven downlink.

The payload is a dual-band infrared imager employing a single optical path and a fail-safe filter selection mechanism to alternate between the 1.27 µm and 4.3 µm channels. The instrument uses a 1024 × 768 detector with an f/1 optical system with a cooled focal plane and dedicated stray-light suppression. In the current sizing, the instrument achieves a representative ground sampling distance of ~7.3 km while covering ~56% of the projected Venus disc in a single frame.

This paper presents the overall mission architecture and design, focusing on key design drivers and baseline system solutions. It highlights the mission phases from interplanetary transfer to nominal operations at Venus, emphasizing differing constraints associated with each phase. An outlook is given presenting the opportunity, feasibility and advantages of a dedicated QUO VADIS pathfinder mission to the Moon.