Titan is among the most captivating worlds in the solar system for several compelling reasons. It possesses a hydrological cycle powered by methane, rather than water. It is the solar system’s second-largest moon, surpassed only by Ganymede, and the only celestial body other than Earth with liquid lakes on its surface. These unique characteristics have made Titan a prime target for exploration, culminating in the upcoming Dragonfly mission.
This innovative project will leverage Titan’s dense atmosphere to power a small helicopter. However, Dragonfly’s design limits its ability to explore Titan’s lakes beyond aerial observation. To address this gap, another mission concept, initially proposed by James McKevitt—then an undergraduate at Loughborough University and now pursuing a PhD at University College London—aims to delve into the lakes both at their surface and beneath.
The mission, which has evolved significantly since its inception, was originally inspired by the diving motion of gannets, seabirds known for plunging into water to catch fish and then resurfacing to fly again. In his initial paper, McKevitt explored the hydrodynamic feasibility of such a probe on Titan, including the complex physics of diving into lakes of liquid methane without compromising the integrity of the device.
Conveniently, Titan’s most intriguing lakes are concentrated near its north pole, theoretically enabling a probe to “hop” between them, provided sufficient thrust and power are available. However, as the concept matured, practical challenges arose. These included the difficulty of achieving the necessary thrust to lift off from a lake’s surface and the energy demands of diving deeply enough into another lake to conduct meaningful research. As a result, the original mission design has faced significant revisions to address these limitations.
One of the primary challenges in the original mission design was the power system. Radioisotope Thermoelectric Generators (RTGs), the only viable option for powering a probe on Titan’s shrouded surface, were deemed too heavy for the mission’s architecture. In response, James McKevitt reimagined the concept entirely.
Amid the COVID-19 pandemic, McKevitt founded Conex Research, an organization dedicated to collaboratively exploring ambitious space mission concepts. Under this think-tank framework, he reworked the original mission, now named Astraeus, into a more feasible design. Details of the revamped mission were outlined on Conex’s website and in an August 2022 press release, revealing a streamlined four-part system.
The centerpiece of Astraeus is the Main Orbital Spacecraft (MOS), which would orbit Titan and deploy two specialized vehicles: Mayfly and Manta. As their names imply, Mayfly would serve as a nimble aerial observation platform, while Manta would dive into Titan’s lakes, fulfilling the primary exploration goals of the original concept. Complementing these vehicles, a series of 2U CubeSats, dubbed Mites, would be released from the MOS to conduct atmospheric measurements during a gradual descent. This multi-pronged approach retains the spirit of the original mission while addressing its practical limitations.
Undoubtedly, the Astraeus mission represents an ambitious undertaking, particularly for a group of nearly 30 volunteer contributors. Despite their dedication and innovative ideas, the scale of the project presents significant challenges. The team last provided a major update when they presented the mission concept at the International Astronautical Conference in 2022. Since then, little news has emerged regarding their progress.
- See also: There was Hot Water on Mars
Nevertheless, if the team continues to refine their plans and overcome technical and logistical hurdles, Astraeus holds the tantalizing promise of one day reaching the depths of Titan’s mysterious lakes. Such a feat would not only be a remarkable achievement for the Conex Research team but also a groundbreaking milestone in humanity’s exploration of the outer solar system.
Learn More:
James McKevitt – ASTrAEUS: An Aerial-Aquatic Titan Mission Profile
Conex Research – The Astraeus Mission to Titan
