In 1620, a persecuted band of English refugees came ashore at what became Massachusetts, to settle a strange and unforgiving new land. Their trials and triumphs — however historically accurate — provide lessons for the extreme hardships humanity could encounter when establishing a society on a new frontier.

These challenges extended beyond those first years and the much disputed Thanksgiving story of tacit cooperation with Native Americans, for which the pilgrims are best known.

There were deeper philosophical hurdles to overcome. Debate began over the establishment of new laws and ideas of justice, over how to best structure this new society. And these questions were amplified as settlers moved west across North America, as conflict with Native Americans intensified, and as settlers spread through what became known simply as the frontier.

Beyond obvious needs for water, food, and oxygen, we’ll be forced to grapple with abstract questions as we forge a home on this hostile and alien world. And conceptualize a new social contract that can be adapted as the first human outposts grow on Mars.

One immediate concern is the establishment of a new justice system.

“If you think of the Mayflower Compact—which was decided before even really setting foot on land—they had an idea of what they wanted their community and their society to be, and it was there from the beginning,” explains Dr. Peggy Macdonald, a public historian and professor of History at Stetson University.

The Pilgrims knew that codifying a legal system in advance was vital to the survival of their colony, and the Mayflower Compact established the laws by which the colony would be governed and judged in a democratic forum.

The colonists formally codified five crimes that were punishable by death. These were murder, arson of ships or homes, rape, adultery, and “forming a solemn compact with the devil by way of witchcraft.” The first settler to be executed was Mayflower passenger John Billington, hanged in September 1630 for murdering a fellow pilgrim after a heated quarrel.

We see this form of social justice in the present-day, amongst isolated and secluded tribes around the world. Christopher Boehm’s Moral Origins finds that modern hunter-gatherer tribes of small numbers employ a democratic social justice system, where the community itself decides what punishment is mandated for disobedience of the group’s rules or laws.

A democratic forum for justice is similar to what Elon Musk has floated in terms of governance on a future Martian colony. "Most likely, the form of government on Mars would be a direct democracy, not representative," said Musk at the Recode conference in 2016. "It would be people voting directly on issues. And I think that's probably better, because the potential for corruption is substantially diminished in a direct versus a representative democracy."

Dr. Macdonald argues that a type of contract like the Mayflower Compact would be vital for any settlement on the Red Planet. “It would seem that on Mars there would have to be a code of some kind that was established in advance so that people can turn to it. There has to be a system that’s been thought out because

But creating a set of guidelines for the administration of justice is one thing. The practical considerations that come into play when applying a justice system are very different.

Take for example a worst case scenario—a murdered body is discovered at the first human settlement on Mars. Murder might be expressly forbidden under all human laws, but in determining the course of justice, colonists will face new and daunting questions.

“Is the colony planning on building prisons for Mars?” asked Dr. Macdonald.  “If you run into a situation where someone murders someone, what do you do?”

No organization talking seriously about a human mission to Mars has discussed this—at least publicly. Even on Earth we don’t have satisfying answers to that question. In the United States, as a case study, the country as a whole doesn't have a uniform standard of punishment for murder. Some states allow execution, the federal government permits the death penalty for certain offenses, and other states outright ban execution.

Sentencing someone to a Martian prison would render them a complete burden, leeching vital resources while giving nothing back. In the United States, it currently costs taxpayers between $30,000 and $60,000 to house an inmate for a single year, having to provide food, shelter, and cover administrative costs. Even with funding, prisons are often cited for inhumane conditions and rights violations that stem from lack of resources or poor infrastructure.

Due to resource pressure, would colonists resort to vigilante “frontier justice” on Mars? Would they feel compelled to take extreme measures outside their legal system—as was the case on the American frontier? Justice on Mars could reduce to a question of how to govern when, in the words of Spock from Star Trek II “The needs of the many outweigh the needs of the few.”

Mars will be a sort of petri dish to examine the limits of our ethics. Removed from the convenience of resources and time that we enjoy on Earth, humans will face brutal questions and decide what it means to be humane as we expand the human footprint into the solar system.