How low can you orbit Duna?

The lowest you can achieve a stable orbit around Duna without encountering its atmosphere is 50,000 meters.

Duna, the reddish planet in the Kerbal Space Program, has a defined atmospheric boundary that dictates the minimum altitude for a sustainable orbit. If a craft's periapsis (the lowest point of its orbit) drops below this altitude, it will begin to experience atmospheric drag, leading to a loss of orbital energy and eventual de-orbiting or crashing into the planet.

Understanding Duna's Orbital Boundaries

Duna's environment is categorized into distinct altitude ranges, each with specific implications for spacecraft operations. These boundaries help Kerbal engineers plan missions effectively, distinguishing between atmospheric flight, stable low orbits, and higher, more distant trajectories.

Here's a breakdown of Duna's orbital boundaries:

• Atmosphere (0 - 49,999 m): Any altitude within this range means your vessel is flying through Duna's atmosphere. While this is necessary for landing or aerobraking maneuvers, it is not sustainable for long-term stable orbits due to atmospheric drag.
• Low Orbit (50,000 m - 69,999 m): This is the ideal range for close-up observations, remote sensing, and deploying surface-bound probes. The lowest stable orbital altitude begins precisely at 50,000 meters, just above the atmospheric ceiling.
• High Orbit (70,000 m - 47,921,949 m): This vast region is suitable for communication relays, distant observation, and setting up transfer orbits to other celestial bodies in the Kerbol system.

To maintain a truly "low orbit" around Duna, ensure your craft's periapsis is at or above 50,000 meters. Anything lower will result in atmospheric interaction, which, depending on your velocity, could be a gentle aerobrake or a rapid, uncontrolled descent. For further details on Duna and its properties, you can refer to the Kerbal Space Program Wiki.