This post is inspired by my recent thoughts on information supply chains providing incrementally more intelligence to an otherwise unintelligible universe. That line of thinking provoked thinking about supply chains in general as a process of taking some form of stock material and adding value to it that some customer may appreciate. However, the motivation for that thinking was a way to approach data science as a supply chain model instead of a single analytic-processing leap from abundant data to an actionable recommendation. The information supply chain model provides refined intelligible data for the final recommending analytic processing, but that intelligible data is traceable back to the original operational data. The intelligibility is added with a goal of satisfying this (among potentially many other) final decision-support analysis.
Truly by coincidence, I have spent a lot of time in recent years in arm-chair engineering mode imagining how I would go about a preparing for a manned mission to Mars. Consistent with my wont, I imagined an alternative to our current plans (approved and supported by the US government).
I imagined the a mission involving thousands of people in space and a good fraction of those would be in orbit around Mars. Actual surface missions to the planet would involve a space elevator approach to support only brief missions of a few hours or a few days to return samples and observations for study at the orbiting station. I’ll describe more about this idea later, but clearly this is not something that we can expect in our current life time. If it does happen, we should start now and commit to a multi-generational object to achieve this 100-200 years from now. It will take that long to build up the supply chains in space, including the supply of humans for the trip.
I will describe some of the complexity of the details later in this post. I came up with the scale of the project by analogy to the European age of discovery in the 16th-19th centuries. Explorations of new lands involved expeditions of multiple ships with large crews. Compared to space travel, the ships had an advantage of access to fresh air and gravity, but they had to carry fresh water and preserved food to sustain the crew. Also, most of the crew were burdened with routine maintenance tasks to keep the ship sea worthy, but coincidentally these tasks kept people occupied during long largely uneventful trans-oceanic voyages. They may encounter some storms or other hazards to avoid, but for the most part the ocean journey was uneventful. The large crew and their various routine duties permitted a development of a human-satisfying experience of participating in a community with shared eating times and periods of recreation (such as game playing).
This internal community aspect was an essential but unappreciated quality for the success of the missions. Another reason for successful missions was that their destination involved dry land that permitted them to restock for fresh water, replenishing food stores, or obtaining fresh timber to repair the ship. Often (almost always) the land they encountered was already inhabited and they negotiated with the local populations to assist in restocking the ships.
The trip to Mars is similar to those trans-oceanic trips in the now distant past. Both journeys involve multiple months of doing nothing but travel. However, as we learned with the international space station in low earth orbit, the duties for routine maintenance consume a lot of time. In the ISS, although the crew are trained for science, most of their time is spent performing low level maintenance tasks. We can expect something similar for the trips to Mars. But even the ISS has the advantage of being only a couple hours from land in case something serious happens such as a medical emergency. The trip to Mars will need to be even more self-sufficient than even the ISS.
Compared to the trans-oceanic trips, the voyage to Mars lacks the convenience of gravity and fresh air. It can be argued the ISS experience demonstrates a tolerance for extended periods of no gravity, but I think a simulated 1-g gravity would be more likely to lead to mission success. That requires larger and stronger vehicle. Supply of fresh air and water will need some machinery or biology to recycle the water and respired air. There will be more equipment to maintain. On the other hand, the trip shares similarities in that it must be self contained. For example, the crew must include training in medical arts to supply appropriate medical (or dental) attention when needed. These activities may require small scale manufacturing to prepare new tools or medications (similar to historic ships carrying their own carpenters and blacksmiths).
I believe a successful journey requires a sufficient population to build relationships that mimic a community. The crew should number in the dozens at least, not just 3-4.
Our current plans for a trip to Mars seems to be pointless and highly likely to fail. Due the duration of the trip and the desire to make the trip in a few years, the mission is minimized as much as possible. We need to keep the crew size to 3-4 in part due to the volume of supplies needed to support their lives for the duration. Also, the entire crew capsule will need to be built on earth and there is a limit to the size that can practically be lift into space.
The entire mission planning for a near term Mars mission is a single-leap approach. We need a single capsule that can withstand the accelerations and pressured of escaping Earth’s atmosphere and orbit, and then permit a coasting phase between planets with sufficient shielding material to protect against direct radiation from the Sun, and then somehow land on Mars to support an extended surface mission, and then somehow launch from Mars to return to a coasting phase only then to confront the challenges of re-entry and safe landing on Earth. Some of these steps may involve smaller specialized components, but certainly the entire mission will need to be manned with just 3-4 people.
I will generously trust the engineering excellence for the mission and that it does not end in catastrophe. I will nonetheless wonder what possible value we will obtain from this trip. I suspect the crew of 3-4 will be completely exhausted doing routine maintenance tasks required just to keep alive, but again I’ll be generous and say the engineering will allow them to perform some real exploration. They are likely to be equipped very minimally. They will not have heavy equipment for serious drilling or grinding. They will not have sophisticate scientific equipment to perform highly specialized investigation of microscopic samples. At best, we will learn a little more about the geology and perhaps answer a question about whether they will find fossil evidence of life. Chances are that they will either find no evidence of life or the evidence will be ambiguous. That discovery doesn’t help us much because they would have only explored one tiny spot on Mars. They could have been more fruitful elsewhere.
Assuming a completely successful round trip mission that may include a few kilograms of samples to return to Earth, about the only value we will obtain is entertainment. Maybe there will be a big celebration for a day or two to honor the returned crew at various cities. We will learn a little more about the planet but that will inevitably lead to effective arguments about why the samples were insufficient or somehow became contaminated. Just as we have never returned to the Moon since the 1970s, we will never return to Mars. The primary motivation was the initial achievement and once that occurs there really is no reason to repeat the task.
I am not optimistic that a short term limited-crew one-time trip to Mars will provide us anything of value. A mission to find evidence of historic life will almost certainly fail and even if it succeeds it will raise more questions than it answers. There will be no effort to perform mining at a meaningful scale or to attempt constructing a useful structure from martian materials.
If the primary purpose of the trip is to provide entertainment for the multitudes of Earthbound people, then perhaps the most entertaining spectacle would be for a dramatic event to occur similar to Apollo-13. The small crew size makes such a drama likely and the resulting drama would risk the lives of just that small crew. Even if it is a perfect set up for riveting entertainment, we could accomplish the same thing with other missions. There will only be one opportunity for claiming to be first to step on Mars. We should exploit that motivation for a mission that actually accomplishes something of lasting value to humanity. If we want to risk a dramatic scenario in distant space, send a crew to a near-earth asteroid.
My mission inspired by the age of discovery is for a much larger expedition. When the first person steps on Mars, there will be tens of thousands of people living in space. Nearly all of these people would have lived their entire lives in space. The first person to step on Mars will almost certainly have lived a life entirely in space. He may with some reluctance explore the planet with a eagerness the opportunity to return to the larger community that resides in the space craft.
The surface mission on Mars will involve very short stays of a few hours or a few days. The exploring team will bring just enough supplies to sustain themselves for that period and to collect some samples. Most of the science occurs on board the orbiting space station. This space station will accommodate a large population. This is a large space station to provide sustainable life support with its own agriculture within a simulated gravity through rotation. The population will provide multiple disciplines including both scientific investigation and engineering expertise to manufacture what is needed new experiments suggested by the latest discoveries.
The orbiting station will be a permanent outpost and may support multiple generations who will spend their entire lives on the station (many never even have the opportunity or even inclination to go to the surface). This stations will be in a synchronous orbit that can change to hover over different interesting locations. The actual expeditions would be through a space-elevator approach of a tethered line that slowly transits the Martian atmosphere to reach the surface. The actual expedition are very light weight because the duration is short and the objective is very focused on obtaining samples. The heavy work and extensive science will occur back at the station.
I imagine this station being permanently in orbit around Mars. There will be occasional transfers with Earth by way of a specialize inter-planetary craft that will support a crew of a few dozen. Due to the duration, this craft will also simulate gravity and have some form of biological ecology to provide at least some contribution to refreshing air, water, and food.
The interplanetary vehicle travels between two permanent space stations. The Earth-bound station will be in a distant orbit (perhaps at lunar distances) and may have a larger population to provide more manufacturing capacity. Again most of this population will have lived their entire lives in space. There is very little exchange directly with Earth.
This mission involves at least two permanent communities in space. These space communities mimic the communities that the old explorers encountered when they reached foreign lands. These space stations provide the equivalent of dry land for the inter-planetary craft to restock itself or to exchange passengers.
The problem of building up the building up the population for this mission is solved from having generations in space. Only a few people will have experience of life on a planet. Similarly, the biosphere of these stations will permit complete life-cycles that enjoy an artificial earth-like environment. This alone means that the project will require many human generations to complete. It may take multiple human generations after the first permanently manned station to obtain the number of people needed to complete the mission to Mars.
These huge self-sustainable space habitats will require a tremendous amount of material. This is far more material than we can expect to launch from Earth. This material will need to come from space, though mining asteroids or the moon.
Mining and manufacturing in space is the key to making this work. The easiest way to establishing a permanent presence in space is to colonize an existing environment suitable for sustaining life. Again I’m making an analogy to the European colonization of foreign lands (for this argument, I assume the lands are uninhabited). The land and its resources are readily accommodating for long term human habitation. For the proposed mission we need similar colonial destinations. Unfortunately, nature offers no habitable options at any of the proposed stops to reach Mars. We will need to create these habitable destinations.
Again, our natural reaction is to envision another earth-based project to send a huge inventory of material and supplies into space to support manned operations for mining and manufacturing. If we are going to all that bother, it is probably cheaper just to revert back to the original plan for a one-time visit to Mars.
My plan is a multiple-century plan because most of the time is required to mine and manufacture in space through automation. The process takes so long because it starts very small. We would launch from earth a single small automated factory that can replicate itself by mining and manufacturing from material on an asteroid/comet.
This mechanical factory may operate in way analogous to a biological cell with different specialized components for harnessing energy, mining raw material, and assembling that material to make a perfect duplicate. The entire replication process may require a long time. The population of self-replicating machines will double for each interval of that duration. The manufacturing will not become meaningfully significant for many replication periods. Eventually the population of replicated factories will become large enough for us to begin harvesting the factories to bring them to another location with another self-replicating factory that disassembles the original factory to reassemble as a larger structure that will eventually lead to a habitable space station.
It will probably take a hundred years to build the first habitable station to begin colonizing with the first permanent space settlement. At that point the in-space automated (remote) mining and manufacturing will continue to grow exponentially. The initial colonizing population will be busy working on completing the habitability of their new homes by establishing farms and building communities. While this is occurring their population will grow. Eventually, when the Martian-orbiting habitat is ready, there will enough space-citizens to start colonizing that habitat.
It may take a generation or two before the Mars-orbiting habitat to begin operating the first elevator missions to the surface. By this time, there will be tremendous amount of space-sourced manufactured materials to make repeated missions practical. Also by this time, the people visiting the planet are content with very short expeditions because they prefer to spend their lives in civilization in the space stations. Eventually, we may colonize Mars itself, but there will not be any rush to do so. We can take our time to plan the best locations and methods for colonization.
By that time there will be also be many attractive space habitats to colonize. Once we figure out how to sustain complete lives in space, there may not be an incentive colonize actual planets at all. The self-replicating manufacturing of asteroids and comets will eventually provide bountiful and cheap material to build very attractive habitats closely mimicking the gravity and environment of Earth. We may decide never to colonize Mars at all, but even if we do we will not be rushed into doing it. We can take our time to devote our time on the surface for scientific discovery and engineering testing before setting up our first surface colony.
In short my plan for visiting Mars is to target a first date of surface exploration maybe several hundred years from now. When we are ready, we will have the ability to sustain a careful study and exploration of the planet for a long duration and thus avoid the mistakes we learned from past explorations where rushed investigations destroyed valuable evidence.
Coincidentally, when we are ready we will have already abundant space-manufactured space stations that are very comfortably habitable with Earth-like gravity (from rotating large structures) and Earth-like climate that will be superior to anything we can hope to achieve on Mars. The infrastructure of automated self-replicating factories will have grown to support building multiple new stations per human generation, allowing for rapid population growth. People accustomed to living in these space stations will not be interested in long stays or colonization on Mars because of the readily available habitable accommodations in new space or growing space stations.
Consider this ultimate end-state of highly populated space stations prior to actual exploration of Mars. By this time we would eliminate the potential benefits of mineral exploitation or habit-building on Mars because we will have superior answers in our space-station habitats and self-replicating mining/factories on asteroids and comets. We can explore the planet leisurely with the focus entirely on science to understand its natural history. We may even decide this is not a priority at all.
With that end state in mind it seems uninteresting to base a space policy on exploring Mars. Certainly we will never gain approval for proposal to justify near terms resources on the prospect of exploring Mars in a few hundred years in the the future. Also, the initial investment in building up the infrastructure for building space-station habits will likely lead to a result presenting little interest in exploring Mars at all.
The above imagined end-state of abundant habitable space stations (eventually rapidly growing in number and size) is attractive on its own right. We will have Earth-like conditions that can accommodate a growing population of people who will live their entire live without ever visiting any planet at all. In addition, the nature of the stations will demand a growing population to support new economies within and between space stations.
Building up the material supply chain based on space-borne mineral resources would be a worthwhile goal to base a long term strategy for exploiting space. By comparison a near-term one-time visit to Mars with a high risk and minimally valuable mission design is a major distraction that postpones the start of what would really benefit us. Instead of preparing for a near-term manned mission to Mars, we should be developing autonomous factories that can mine resources of an asteroid to replicate themselves so that the mining and manufacturing will accelerate over time. Eventually, we can collect the excess replicated factories and re-cycle their material to build larger structures (perhaps also autonomously replicating) that in turn can supply materials for building habitable space stations. Once we begin colonizing the habitable space stations, the economy will eventually grow to the point where living in space will be more economically appealing to living on Earth. Before that point occurs, access to space mined and manufactured products can provide economic benefits to the Earth-based economies.
We could be focusing on building a material supply chain in space instead of fragile missions for immediate manned exploration.
The above scenario lacks engineering details to be taken seriously. I could spend even more time describing even more fanciful thoughts about how miniaturized self-replicating factories may operate and how they may become part of an entire ecosystem (mimicking a food-chain) of self-replicating factories of higher purposes. I like the idea but my mental investment in this concept hardly rises to a level to support even a mediocre science-fiction story.
The story does provide an analogy to my earlier points about information supply chains for developing intelligible data for data science. In my experience, the autonomous intermediate steps in the chain worked analogously to the above scenarios of mining raw material that eventually build intermediate space stations that eventually permit a serious exploration of Mars. Replace the goal of exploring Mars with the goal of supporting decision making, and replace the material and population of space stations with data. An information supply chain not only operates similarly, but also comes about in a similar manner. The final goal of decision-support analytics becomes possible because we had previously met intermediate goals of analytics to support lower-level decisions. The information supply chain builds up over time based on the earned trust of the intermediate analytic results that serve as data for the next higher level of analytic. In either project, the ultimate goal is met from progressive advancements building on earlier achievements.
4 thoughts on “Realistic plan for sending humans to explore Mars”
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Buzz Aldrin wrote a book about a mission to Mars:
His plan gets to Mars quicker than my plan.
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