The Open Problems

Statement

Can a human pregnancy go to term in Mars gravity (~0.38g)? So far, no mammal has completed a full reproductive cycle off Earth. Mouse and rat studies in microgravity show developmental abnormalities. We have no idea whether a human child can be conceived, carried, and raised normally outside Earth's gravity well. This is the central question behind continuity of human life.

Statement

Nobody has a tested system for selecting, training, and supporting crews of 50+ people for missions exceeding 12 months. Analog studies like Antarctic stations, Mars-500, and HI-SEAS have all been smaller and shorter. The published data on faction formation, hierarchy collapse, and mental health degradation in confined groups beyond Day 200 is thin.

Statement

ISS water recycling historically achieves ~93%, with recent Brine Processor demonstrations reaching ~98%. Sustaining 98%+ as a long-term operational standard requires advances in scrubber reliability and microbial control. A demo is one thing; years of daily operation is another. Each percentage point of recycling efficiency saves several tons of launched mass per year of mission.

Statement

Spaceflight-Associated Neuro-ocular Syndrome causes structural changes to the eye and optic nerve in long-duration crews. The mechanism is still unclear. It could be intracranial pressure, venous return, or something else entirely. Some of the changes look permanent. There is no effective countermeasure yet.

Statement

Galactic Cosmic Rays (GCR) go straight through spacecraft hulls. Long-term exposure increases cancer risk, and we do not have a good dose-response curve for HZE particles in humans. Effective shielding requires either thick mass like water or regolith, or electromagnetic active shielding that has never been tested.

Statement

ISS crews exercise 2+ hours daily and still lose 1-2% bone density per month. You cannot ask every person in a colony to work out like a professional athlete forever. That exercise burden does not scale. Pharmaceutical countermeasures, artificial gravity, and other approaches remain unvalidated for multi-year exposure.

Statement

Existing ISS food production experiments grow grams of leafy greens. Feeding 100+ crew takes hundreds of kg per day. That means solving lighting energy budgets, pollination, water cycling, soil substitutes, and pest management. None of those have been demonstrated in microgravity or partial gravity.

Statement

A Mars-bound crew faces 4-24 minute one-way communication delays. Current mission protocols assume real-time ground support. Crews must be able to autonomously diagnose, decide, and act on complex emergencies without external input. No training framework currently certifies this capability.

Statement

A Mars colony cannot wait 6+ months for replacement parts from Earth. That means manufacturing on-site: 3D printing with Martian regolith, recycling failed components, producing safety-critical hardware to spec. This capability does not exist yet.

Statement

On the ISS, an astronaut in psychological crisis can be evacuated. On Mars, that option disappears. There are no protocols, pharmaceutical stockpiles, or treatment frameworks designed for severe mental health emergencies in crews where return to Earth is impossible.

Statement

Who is in charge of a Mars colony? What law applies? How are crimes prosecuted? Who decides when supplies run low? These questions have no agreed-upon answers, and they will become urgent the moment the first colony of more than 25 people exists.

Statement

What does a Mars colony do if Earth stops sending supplies? That could happen because of pandemic, war, economic collapse, or political reversal. The minimum viable self-sufficiency threshold is unknown. The transition plan from Earth-dependent to Earth-independent has not been designed.