Closed loop life support not required

Is it required to colonize mars? This older article says...

For the International Space Station, the crew and operations resupply requirement is about 10 kg per person per day. The ISS will typically have a crew of four; in 90 days it needs 900 kg per person; 3600 kg for the crew. This is easily within shuttle capabilities, even the capabilities of a crew and cargo vehicle flying on an ELV. There is little motivation to do better.

A Mars proto-settlement of 1,000 people is a lot different. Such a settlement is not feasible with this state of technology. Consider 1000 people, 365 days, at about 10 kg/day. This figures to 3.65 million kg (about 8 million lb) per year. Even at reduced launch cost of $1,000/lb, the delivery cost to Mars is at least $5,000/lb. The annual cost therefore is $40 billion just for life support. No government or consortium of governments will put up with such high cost, and it is out of the question for the private sector. [I propose zero resupply.]

Bioregenerative technology is needed. This technology is also highly applicable to cleaning up our environment here on Earth.

A permanent outpost needs a closed micro-ecology or something close to it. This means full recycling of all life support supplies, including waste and garbage. Periods of "no opportunity" for Mars resupply last almost two years; transit times are six months or more. Not only is the cost infeasible for ISS-level technology, the masses to be transported are outrageous.

I've been using 8 kg per person per day, but let's go with 10 kg. First, that $40 billion is bogus even in their scenario. Nobody today would propose all supplies come from earth. You also have two different scenarios to consider, getting to mars and living on mars.

Getting to mars takes about 250 days or 2,500 kg per person. Not outrageous. It's actually much less since 75% of that is water which we can recycled pretty well. So well, that they may dump most of that water before doing a mars orbit insertion burn. Ok, so let's look at those 1,000 people on mars...

They don't need any life support from earth after an initial bit to get them started. Everything they need other than plant seeds (the perfect low mass space travelers) already exists on mars. So instead of 3.65 million kg they only need enough to get production started. Water production can be started before any colonists even arrive. They aren't going to have 1000 colonists all at once. Perhaps a dozen on the first landing that will prepare for the 3 to 5 dozen arriving two years later. Those will then prepare for the hundreds that follow every 26 months.

So you need freeze dried food for a dozen with emergency backup until local production gets in gear. Say 300 days times 0.62 kg of freeze dried food times 12 colonists. Let's call that 2500 kg (2232) which fits on one $150m lander. We could easily send more if required. $40 billion is a scary number. $150 million, not so much. Let's also not forget the arriving colonists will bring between 2 to 10 weeks of life support with them. Some of that can become emergency reserve.

Even biosphere II was a success when you realize a closed loop is not required.