Moon to Mars Part II: Evolving to Mars

This is a joint article between Beverly Casillas and Scarlet Dominik.

Artemis’ stated goal to “prepare for human missions to Mars” is an ambitious undertaking, with visible consequences on its organization. With Artemis entering flight across its various programs, and hardware which will eventually support its primary missions in flow, we have entered a unique era for spaceflight. For the first time ever, substantial hardware is in flow for a program that seriously aims to someday send human astronauts to Mars. The entire structure of the Artemis program is built around this ultimate goal, and the establishment of a sustainable lunar presence to act as a foundation towards it.

The plan for Mars currently exists as a trade space, far from a complete roadmap with any specificity. In this trade space various options are studied intensely to consider all possible challenges and investigate potential solutions based on technology both forthcoming and currently available. These studies break down a variety of topics. They can analyze the possibilities offered by emerging technologies while weighing them against current capabilities, or describe in detail the environmental dangers associated with a trip to Mars, or any other relevant open question no matter how specific.

Studies like these are not meant to represent a final plan, or even a preliminary one. Instead, what NASA gains from each study is an exercise in understanding how different assumptions and constraints influence the architecture that will ultimately be designed. A mission to Mars has never been meaningfully attempted before, so while a solid “Mars plan” does not exist yet, each study can hone in on specific unanswered questions. Each one is written by different authors, with different priorities, and different levels of knowledge about different kinds of technologies. None of these studies solve the problem on their own, but together, they form a vast library of knowledge–a great catalog of options and ideas to draw from once mission planning is ready to begin in full. For now, NASA is focused on identifying and answering the highest level questions raised by a Mars mission.

To go about this systematically, NASA has recently developed a new method for its  big-picture planning called “architecting from the right.” In this process, the agency begins by defining its goals and objectives at the highest level, and then works backwards to understand what capabilities and systems it will need to accomplish them. This procedure, culminating with an annual Architecture Concept Review, ensures that nothing gets developed without a clear purpose, and allows NASA to consciously invest in technologies and programs that will be most useful in the long run.

To define these high-level goals, NASA has focused on six fundamental questions about its Mars ambitions. Simply put, these are the Who, What, When, Where, Why, and How of the program. The most important of these is to establish “Why” – what makes human exploration of Mars worth doing? NASA has responded with three guiding principles: Science, Inspiration, and National Posture. Every future decision throughout the program will strive to espouse these ideas, ensuring that past motivations like haste and spectacle do not detract from the practical goals of human exploration.

Key Mars Architecture decisions

One of the most daunting things about planning a crewed Mars architecture is the sheer number of decisions that must be made. Every choice has cascading impacts down the line, eliminating some pathways and opening innumerable others. It may be tempting to simply pick a direction and start following it, but in a project this challenging – likely to span decades and hundreds of billions of dollars – we do not have the luxury of trial and error. A misstep at the outset could make accomplishing our goals unreasonably difficult years later. As NASA puts it, “Every decision is important, but not every decision can be first.” How, then, do we chart a course through this maze of possibilities?

To address this challenge in its Moon to Mars Architecture, NASA has turned to history. During ACR23, experts reviewed years of past Mars mission studies to gain a deep understanding of key architecture decisions. They focused on decisions with the biggest impact on the overall architecture, as well as the biggest impacts on each other, producing a spiderweb of interlinked pathways.

Ultimately, NASA has selected seven key architecture decisions that must be made first. These are the decisions from which all others will follow, and which most directly influence how the agency will accomplish its overall architecture goals. Each of these decisions also reflects the six architecture questions presented above. They are:

• Mars Science Priorities (Why do we go?)
• Initial Human Mars Segment Target State (What capabilities do we establish?)
• Initial Human Mars Segment Mission Cadence (When can we go?)
• Mars Loss of Crew Risk Posture (How do we manage risk?)
• Number of Crew to Mars Surface (Who do we need on the surface?)
• Number of Crew to Mars Vicinity (Who do we need in space?)
• Primary Mars Surface Power Generation Technology (How do we power assets?)

Most of these are not choices related to specific hardware, but high-level decisions about the specific problem the architecture will attempt to solve. These foundational decisions will define the overarching vision for NASA’s crewed Mars exploration program, and begin to paint a picture of what our first steps on the red planet will look like. Additionally, as more detailed decisions follow, they will help us to identify the key technologies we need to develop right now, so that they will be ready when it’s time to make the voyage to Mars.

So, when can we expect these decisions to be made? Since completing ACR23 last fall, NASA’s architecture teams have been hard at work studying their options and the consequences of each of these key decisions. During the next review, ACR24, scheduled to be held this November, NASA expects to produce recommendations for at least a few of these questions. These will be the first formal architecture decisions for a crewed Mars program in the agency’s history.

In the meantime, we can look elsewhere to understand where NASA stands on these issues. The ACR23 product release in January of this year included a series of “White Papers” that explain some of the key factors driving each of these decisions. Other outlets, such as public NASA committee meetings, have provided further insight. For example, Michelle Rucker, NASA’s Mars Architecture Team lead, has recently expressed that the question of Mars surface power is one that the agency understands quite well, and that ACR24 will likely recommend the use of nuclear power. These and other resources can help us understand the current balance of the Mars architecture trade space.

Moon to Mars Transferability

While the nature of Mars architecture as a trade space may lead one to believe NASA’s Mars ambitions exist purely as ideas, and no material hardware is being worked on, this is not true. In fact, technologies most foundational in their importance to a mission to Mars are not only in active research and development, but some are rapidly approaching flight. As previously described in Space Scout’s Anatomy of a Deep Space Transport propulsion systems and fuel infrastructure capable of supporting a vehicle which could carry a crew to Mars are vital elements. These elements are so vital, and hold so much potential, that no matter what method NASA chooses for Mars, all of them need to already be in flow – and they are.

While nuclear propulsion is being developed through DARPA’s Demonstration Rocket for Agile Cislunar Operations (DRACO), high-performance solar-electric propulsion (often abbreviated as “SEP”) systems and in-space cryo-fuel delivery and boiloff management (sometimes abbreviated as “Chem”) are being directly developed as part of the Artemis Program’s pursuit of sustainable lunar exploration. SEP will be flown and operated by NASA’s Gateway Station, while Chem technologies will be spearheaded by SpaceX and Blue Origin, NASA’s contracted providers for the Human Landing System.

As NASA explores the Moon with astronauts under the Artemis Program, mission goals will not be strictly limited to scientific study of lunar geology. Some missions, such as Fission Surface Power which is expected to be delivered by a future CLPS mission, will demonstrate the capabilities and applications of new technologies in support of lunar operations. This however is not the ultimate aim of such technology demonstrations. Broadly speaking, the delivery and prepositioning of hardware in support of human explorers is a necessary operation for worthwhile exploration of Mars.

Just as various propulsion systems are being developed in hopes of someday supporting missions to Mars, so too are these other technologies. Gaining experience developing, deploying, and operating with nuclear power on the Moon could directly translate to nuclear power on the surface of Mars. Nuclear power alongside other elements such as pressurized rovers, surface habitats, deep space resupply logistics, new robotics technology, and more come together to form a “toolbox” of options. From this toolbox, many demonstrated technologies will be on the table for utilization by future Mars architecture. Not all technologies which are demoed on the Moon will have their implementation directly applied to Mars, for various reasons (such as environmental differences), but the existence of these technologies and experience working with them will be a critical asset.

The Moon is a much lower-risk environment than Mars. Reaching the Moon is easier and costs less, and in the case of an emergency abort scenarios are well understood, Earth is only days of travel away. If these technologies waited until Mars was the sole focus, it would not only limit mission planning options in regards to the technology available, but would give little time to buy down the risk of these assets. Experimental demonstrations can be allowed to fail on the Moon in a well-controlled environment so that matured assets can work reliably on the path to Mars.

Conclusion

While many argue that Artemis’ complexities in regards to the Moon are wasteful in comparison to a more direct approach like Apollo’s, all of the pieces of the Artemis Program are arranged to provide a foundation to go further. The Apollo Program’s ultimate aim was to reach the Moon before 1970, and as such the program was organized and its hardware built in aim of that singular purpose. Because of this, Apollo did not survive even 4 years past its first landing, did not complete all of its scheduled landings, and left no means for a successor program to reach the Moon.

Conversely, the Artemis program fits into a plan much bigger than itself. Mars mission concepts have been studied for decades, with each one further developing our understanding of the problem at hand. Now, as NASA begins to make these hard decisions for the first time in its history, the Artemis program acts as a crucible to forge the strategies and technologies that will enable us to go beyond the Moon.

As part of our series on NASA’s Moon to Mars Architecture, Space Scout will dive into the agency’s wealth of published resources to help demystify the finer details of the Mars mission trade space. Although NASA’s approach to architecture planning can seem opaque, following the process can lead us to a deeper understanding of just what it will take to send humans to Mars.