On the feasibility of a lighter-than-air platform for Martian exploration

Lighter-than-air platforms are currently gaining the attention of engineers for diverse applications. Beside their superior endurance performance granted by buoyancy as a means for countering weight, electric motors coupled to propellers, with their high thrust-to-weight ratio and small size, allow designers to deploy them within the topology of a novel airship, thus mitigating the inherent controllability issues of these platforms.

Among the missions currently envisaged for airships on Earth are high-altitude pseudo-satellite (HAPS) applications, where the ability of the airship to reposition, further increase its own flight time through solar energy harvesting, and return to base after a long-endurance flight, constitute an interesting alternative for surveillance and intelligence gathering missions traditionally associated with space satellites. Furthermore, the atmospheric and irradiance conditions encountered in the layers of the atmosphere at 18–20 km of altitude are partly similar to those found on non-terrestrial bodies. This naturally suggests an application of airships for non-terrestrial exploration especially on planets where a sufficiently dense atmosphere is present.

Lighter-than-air applications (notably, uncontrolled balloons) have already been attempted on Venus, along with preliminarily studied in the past for both Venus and Mars. However, most of the literature is less recent than the latest developments in technology, especially in solar cells and envelope material, besides that of electric motors and batteries, which nowadays can be exploited to reduce the weight and size of an unmanned airship.

This study, grounded on a pre-existing method for the preliminary sizing of airships already employed for several terrestrial applications, tries to fill this gap by analyzing the sizing solution of an airship for Martian exploration through a parameterized approach. This allows us to study the effect of different technological choices on the sizing solution, highlighting the most relevant bottlenecks towards the feasibility of this concept, dictated by constraints on geometrical dimension and mass.