When humans finally colonize Mars, everything will be recycled. Nothing will go to waste. Certainly not valuable organic material, which can be used for everything from compost and fertilizer to starter for growing lab meat.
It is thought that terra-forming Mars at any significant scale will take millions of years. Until the time microorganisms, plants and animals populate Mars, we will dependent on whatever organic material can contribute to the growth or production of food.
I’m quite sure they won’t be burying the dead, as the ground is hard and frozen. Without oxygen, they won’t be cremating them either. The need for regular production of food will be paramount, and this need will supersede the maintenance of taboos cultivated on Earth.
Consider the high rate at which developing embryos fail here on Earth. The complexity of the human brain engenders a trade-off. No mammal on earth exhibits the rate of failure associated with human pregnancies. Ergo the frequency of partial or complete reabsorption of the foetus, as well as stillborn events.
Urine will be recycled to drink; feces will be coveted for the nutrients they lend to plant growth.
I imagine a restaurant on Mars outfitted with food printers. The “ink” loaded into such printers will be derived from collagen, protein, and cellulose. The only reliable source for this “ink” will come from the colonists themselves. These dishes may well mimic the foodstuffs we crave on earth in taste, color, and texture. Lighting, Holograms and mood-enhancing drugs may further help to reproduce the pleasurable experience of dining here on earth.
The post-war story “Soylent Green” imagined cadaver-derived food production methods on a post-apocalyptic earth. But on Mars there will be no need to hurry death toward these ends. Sickness and dysfunction in embryos and adults will be insured by extreme conditions on Mars. Cosmic rays and extremely low gravity will compromise the development of embryos, as well as our senses and organ function. Extreme temperatures, lack of oxygen, and the probability of deadly viral outbreaks in cramped, contained micro-environments will further stress those who bravely venture where no man has gone before. Yes, we will have new ways to limit these dangers. But we will also be surprised by unexpected stressful events.
The need initially for contained micro-environments will severely limit – if not preclude – the introduction of familiar flora and fauna on Mars.
Taboos develop and change based on pressures acting on communities. Significant pressure to evolve and adapt will ensure the rapid shift of some of our most dear beliefs.