Bishop Thomas John Paprocki | Diocese of Springfield

The Catholic Church has not issued a definitive teaching on the ethics of colonizing other planets, such as Mars. However, Church tradition and moral theology provide several guiding principles for considering the morality of space colonization.

Father Christopher Trummer, S.T.L., parochial vicar at St. Boniface Parish in Edwardsville and associate chaplain of the Springfield Chapter of the Catholic Physicians Guild/Catholic Medical Association, outlined these principles in response to a question from a community member. He stated that while settling on another planet is not inherently immoral, it brings significant moral responsibilities.

He explained that any efforts to colonize space should be aligned with God’s plan for humanity and creation. According to Father Trummer, key moral considerations include stewardship rather than exploitation, service to humanity instead of personal gain or pride, respect for life and creation—whether known or unknown—and upholding human dignity both on Earth and beyond.

Quoting the Second Vatican Council’s Gaudium et Spes (33-34), he said: “Through science and technology, [man] has extended his mastery over nearly the whole of nature… . This human activity accords with God’s will. For man, created to God’s image, received a mandate to subject to himself the earth and all it contains … .”

Father Trummer suggested that this principle of stewardship can reasonably extend beyond Earth. He referenced St. Ignatius of Loyola’s Spiritual Exercises: “Man is created to praise, reverence, and serve God our Lord … . The other things on the face of the earth are created for man to help him in attaining the end for which he is created.”

He also addressed modern ideologies that place planetary or animal life above humans and cited St. Paul: they “exchanged the truth about God for a lie and worshiped and served the creature rather than the Creator” (Rom 1:25).

Father Trummer noted Elon Musk’s advocacy for Mars colonization as an example from outside religious circles. Musk views Mars settlement as a way to preserve humanity in case of disaster on Earth but stresses that scientific ambition must be guided by moral truths: “What is technologically possible is not always morally justified.”

The Compendium of the Social Doctrine of the Church states: “Scientific and technological progress, which contemporary man is continually expanding in his dominion over nature, must be oriented to the development of the whole person and of all people. Science and technology are ordered to man … hence they find in the person and in his moral values both their point of departure and their goal” (n. 464).

According to Father Trummer, creation should be used responsibly—not treated as personal property—and stewardship should involve gratitude, humility, restraint, and consideration for future generations. If survival requires leaving Earth due to catastrophic conditions despite best efforts at preservation here, seeking new habitats could become a necessary act.

He cautioned that attention given to space exploration should not detract from urgent needs on Earth such as poverty or environmental issues. Mars should not be seen simply as an escape plan; care for Earth remains paramount.

Should settlement elsewhere become necessary for survival, Father Trummer argued that access must be equitable—not reserved only for elites or controlled by one nation or corporation—and must protect human dignity through ethical treatment of settlers.

He concluded: “The Church does not fear space. Creation is a gift, and humanity’s exploration of it can reflect God’s unfolding providence. The possible colonization of Mars should not be seen as a conquest, but a new frontier approached with humility, solidarity, and awe — guided by truth, love, and justice.”

“When I see your heavens, the work of your fingers, the moon and stars that you set in place — What is man that you are mindful of him, and a son of man that you care for him? Yet you have made him little less than a god, crowned him with glory and honor.

You have given him rule over the works of your hands, put all things at his feet” (Ps 8:4-7).

Father Christopher Trummer holds advanced degrees in Sacred Theology from Rome.