Will Humanity's Economic Cost Hinder Interstellar Missions?

Interstellar travel remains one of the most compelling and ambitious endeavors for humanity, but many factors come into play when considering the feasibility of such missions. The economic cost is one crucial element that could either enable or hinder these missions. As the global population begins to decline and our wealth might stabilize or even decrease, how might this impact the potential for humans to venture into the cosmos?

Key Questions for Feasibility

Several key questions are central to whether interstellar missions with humans become feasible:

Will humanity continue to grow in wealth? Will our wealth stagnate or decline as the global population decreases? Can humans travel at the necessary speeds for interstellar travel?

Current discussions about these issues highlight the complexity involved in achieving interstellar travel. While it might be technically possible, economic feasibility is a significant barrier.

Human Ingenuity and Nanocraft

Despite these challenges, human ingenuity does not cease to amaze. Some believe that nanocraft could play a crucial role in achieving interstellar travel. The Breakthrough Starshot project, for instance, is a grand initiative aimed at developing chip-scale spacecraft to travel to nearby stars. The project is driven by the hope that nanocrafts could make interstellar travel a reality.

Others like Kim Stanley Robinson, in his novel Aurora, suggest that humanity might achieve interstellar travel through a different approach. In his work, the focus is on space colonies that would establish themselves in interstellar space and communicate via radio while interacting with neighbors. These colonies would not travel much, but they would capture comet bodies to collect materials for survival.

Slower Interstellar Travel

A common oversight in discussions about interstellar travel is the idea of slower methods. In interstellar space, distances are vast, but relative velocities can be quite small. Instead of rapidly accelerating and decelerating ships, colonies could use slow methods like asteroid mining, such as using linear magnetic catapults to throw rock-dust for propulsion.

Similarly, interstellar ships could be designed to travel at much lower speeds. For example, a ship with a speed of .15c (15% of the speed of light) could theoretically traverse 100 AU (astronomical units) in 17 days at peak cruising speeds. Although such ships might never travel between stars, a colony could eventually attach itself to a comet falling towards another star. The only "economics" involved would be the need to capture another comet before running out of materials from the current one.

Large-Scale Feasibility

On a large scale, interstellar missions might not be economically feasible using conventional methods. The journey to even the closest star system, such as Alpha Centauri, would take centuries or millennia. This raises several questions:

What would people do once they got there? Would return journeys be feasible? If not, what's the point?

Given these challenges, it is likely that humanity will remain confined to the solar system as long as the species and its descendants continue to thrive.