A better reason for space expansion?

In October 2020, a white paper on planetary protection was submitted to the 2023-2032 Planetary Science Decadal Survey. In the white paper, the authors outlined their concerns about how human practices in space would impact the local environments of potentially habitable planets if an indigenous biosphere was present. They also compared the current commercialization of space to European colonialism. One particularly controversial point was their suggestion that humans should rethink going to Mars in case it had a native biosphere that could be at risk from microbes introduced by humans, though they stopped short of saying humans should not go to Mars at all. Preventing contamination via a robotic spacecraft is one thing but preventing biological contamination with humans present is much more challenging. Humans are essentially walking microbiomes.

This suggestion prompted an emotionally charged and somewhat inflammatory, but articulate, response from Robert Zubrin, president of the Mars Society who accused them of being “wokeists” trying to hold back human progress and imprison humanity in its cradle. Suffice to say, it caused quite a stir at the time.

This incident gives more context to an article I recently came across arguing that “space capitalism” would mean the destruction of the space environment in the name of profit. Although the article has a clear political angle, preservation of the space environment is a genuine concern in the astrobiology community as humans begin to expand farther into deep space. Admittedly, humans do not have the greatest track record for preventing unintended ecological destruction from the introduction of biological invaders. Our collective human reputation for interaction with indigenous cultures is even worse.

As I have argued before, more space advocates should care about the environment and more environmentalists should care about space. They depend on each other. We cannot expand into space without understanding how ecology works so we can replicate it in future space habitats. We will also be limited in our ability to care for the planet if we do not have satellite arrays to monitor the climate or a planetary defense system in place to deflect hazardous asteroids.

I have three proposals that could help us to ethically settle space and not make it essentially “space colonialism,” where humans expand into space with little regard for the impacts on the local environment and indigenous life. The first is to change the narrative for why we want to be in space. The second is to limit our destinations and the third is to prioritize sustainability over growth once we have a permanent presence in space.

Changing the narrative of human expansion into space

Currently, the justification for going into space promoted by many well-intentioned space advocates is largely profit-based. It makes sense to focus on economic considerations when finding a reason to expand into space. If humans are to go into space, they will need to make a living somehow. The problem with making this the primary justification for space development is that it ends up making the development of space all about what we can get from space in order to make more money. Instead of the space environment being something that is valuable in of itself, it becomes just another stockpile of resources to exploit. With this attitude, it is likely that much of the spiritual, aesthetic, and scientific value inherent in the space environment will be sacrificed in the name of profit. With this attitude, we risk making the majestic landscapes of the Moon and Mars into mining pits and causing the extinction of potential exo-biospheres on Mars and ocean worlds across the solar system.

What if instead of financial profit, it was a desire for a deeper connection with the cosmos, to relate with it, and let it shape us a human beings that drove our expansion into space? The German political philosopher Oswald Spangler believed that the land shaped a people and formed certain values and attitudes in them. What sort of values and attitudes might be shaped in the minds and hearts of future space settlers by their environment?

This proposal is somewhat mystical, but I believe that most people who want humans to be in space would agree that this is their real motivation for going into space, not so that they can get rich from extracting platinum group metals from asteroids or converting lunar water into fuel (as vital as those tasks are for creating the economic foundations of a space society). Most people who want to go into space want to go because they feel connected to it in a mysterious way, which I will call a spiritual connection, and they want to deepen that connection. It could argued that having this spiritual connection to the cosmos beyond Earth does require us to be there for a significant period of time, just like having the deepest possible spiritual connection to a land requires you to actually live there for a time. Therefore, we want to go to space so that the cosmos can shape us in some way, not just to extract resources.

Limiting our destinations

A practical expression of this attitude could be to intentionally limit our destinations in order to preserve the most precious aspects of the unaltered space environment, particularly extraterrestrial life. This might mean choosing not to settle Mars or another habitable planetary body if they turn out to have life. It may also require making sure a planetary body does not have any extant life before sending humans there. If Mars and the ocean worlds are off-limits though, this does not mean that we cannot go elsewhere. There are many places in the solar system that have the resources that humanity needs to survive or make a living which are very unlikely to have indigenous biospheres. These include Luna (Earth’s Moon), Mercury, asteroids, and cometary objects. It could even be argued that there is an advantage with some of these bodies over a planet like Mars. Settling an asteroid, for example, does not require going down another gravity well or burning through an atmosphere. Asteroids could also be made into generation ships which could be used to travel into the outer solar system or even to other star systems, something that would be harder to do with Mars.

Prioritizing sustainability over growth

Currently the economy in deep space is pretty close to zero in its capacity to support a spacefaring society. Some growth will be required if we ever intend to even have human settlements or industry as far as Luna, let alone Mars and beyond. Once we are permanently in space though, it could be argued that the focus should be on sustainability rather than growth. Growth can be good, but too much can be harmful. It is good for a child to grow in stature, but if the child is already over 11 feet tall, then the growth has become unhealthy, even pathological. To avoid unhealthy growth, the focus of the economy should be on sustainability with growth being pursued when necessary to ensure sustainability. The main focus of the space economy should be to create an environment in which humanity and other living things, whether from Earth or extraterrestrial in origin, can thrive and to keep that environment going for as long as possible. Sustainability thus becomes another way of saying long-term survival. This does not imply stagnation since sometimes long term survival does require change and growth while other times it requires holding things stable.


Expanding into space for the value of space itself as opposed to economic gain, limiting our destinations and prioritizing sustainability over growth mirror what we need to do on Earth in order to continue to survive and thrive on this planet. We need to value Earth’s environment for its own sake not because of what we can get from it. We also may need to limit the areas of the planet we expand into to protect biodiversity and not infringe on the lands of uncontacted people groups. Furthermore, we need to prioritize sustainability over growth in our economic development to learn to live within Earth’s limits. In this way, the things we need to do to live in space long-term are the same things we need to do in order to live on Earth long-term.


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