The Space Reviewin association with SpaceNews

analogue mission
Analogue missions are intended to prepare for future human missions to places like the Moon and Mars, but depending on how they are designed may not be that useful.

More space on the ground: trendy analogues vs. an unpleasant reality

Bookmark and Share

The astronaut job is probably the only one that is at the same time both the most wanted job in the space sector and one of the silliest expectations someone may have as a career goal. Still, it is a job! There are high hopes for upcoming human spaceflights, and the commercial astronaut job is slowly opening the door to new types of astronauts. However, such a “silly expectation” drives people to find new opportunities to become astronauts no matter what. Thus, the boom of analogue astronauts has started!

Being an analogue astronaut is a symbol showing that a person is figuring out their way to get to space.

Analogue missions are activities run to simulate part of the complexity of a crewed mission on the ground and represent a possible future scenario of human life on the surface of a planet. Participants are analogue astronauts, meaning that they do (or play!) the role of astronauts. Such missions are—or at least are supposed to be—the groundwork for future human missions on the surface of the Moon, Mars, and beyond. The use of analogues has slowly moved from being an essential platform for supporting science to becoming a way of self-expression, almost disconnected from its original connotation.

At the very beginning of human spaceflight, human activities at the poles or desert expeditions were a reference for understanding insights of human life in space, as people face similar life-threatening conditions. The term “analogues” became popular at the end of the 1990s, when scientists increased the number of testing on the ground for supporting ongoing activities in space. In 2001, The Mars Society, a non-profit organization, established one of the first facilities, known as the Mars Desert Research Station, entirely dedicated to run missions open to space enthusiasts too. Today, private companies and many other non-profits are running analogue missions, and joining one is almost trendy in the space sector.

Indeed, a mission is a chance for turning high hopes into a reality, albeit temporarily. Many are dreaming about future societies in space, built on the best of current progress, where humans will live in harmony with the surrounding nature. Analogues are like a stage with a global audience and are used for raising community awareness about topics not yet fundamental for sustaining human exploration of space, such as art, religion, communication, and others. Being an analogue astronaut is a symbol showing that a person is figuring out their way to get to space. Such astronauts are closer to visionaries than to explorers, almost like pioneers of future scenarios.

As one might expect, the number of these scenarios is increasing, along with the number of people taking part in analogues. Here, the message behind an analogue may be more important than the realism of the mission, regardless if it brings an added value to the current scientific efforts of human missions. Ideally, any trial should be designed and implemented as if it was a piece of the puzzle of incoming crewed missions. However, the underlying system supporting analogues is so fragile that there are significant limitations in building upon each others’ efforts.

There are no universal guidelines on how to design an analogue mission, and participants are free to follow approaches different from those used by space agencies. Consequently, many improvise organization and adopt personal metrics for setting safety without even realizing possible consequences.

The lack of universal policies enabling multilateral cooperation and interoperability is one reason for promoting several variabilities in the three main aspects of the mission design: science, implementation, and operational value. The scientific community may help to improve just the scientific aspect, until the impact of the mission design is deemed not a priority. Spaceflight operations are addressed towards implementation in outer space, while analogues run several studies for scientific purposes. When implementation comes with operations, scientists will include aspects arising from the interdependence of multiple studies. For example, sample collection procedures should account for the accumulated workload and stress. A policy environment, built on space law and international legislation, may drive analogues in a way that scientific efforts cannot, conferring them an operational value that would bring benefit to space agencies and private companies. Instead, safety would still be open to interpretation due to the lack of an entity mediating the implementation of the right of health, like space agencies do for human missions.

There are no universal guidelines on how to design an analogue mission, and participants are free to follow approaches different from those used by space agencies. Consequently, many improvise organization and adopt personal metrics for setting safety without even realizing possible consequences. Safety guidelines are not a responsibility of those owning the facility. So far, safety is a responsibility left to those with knowledge in this field and Good Samaritan common sense. An informed consent, a code of conduct, and rules for using the facility are a few of the papers requiring a signature before the start of the mission. Such documents do not embrace safety as meant in operations and, in many cases, it is the only common part that such missions have. Limitations in resources, logistics, and knowledge may play a part, but the underestimation of this scenario is quite concerning.

Selection criteria build on local legislation and, in a few cases, on requirements set by the crew. An example is requiring an active FAA medical certificate (class 2 or 3) used in aviation to state that pilots are in good health. A physician (or someone asking as such) shall consider medical history, and limitations in aiding, among other issues. There is no entity suggesting the type of medical kits or pharmaceutical drugs to use during a mission. Identifying the roots of possible medical emergencies can become quite tricky when there are no guidelines. Also, few studies report relevant lessons learned in this field. Participants may tend to overperform when sponsors are covering part of the expenses of a mission, and it is one of the reasons for which most missions are self-declared to be successful, minimizing medical emergencies. As if that was not enough, the perception of a medical emergency diminishes on the mission as the alertness level decreases. Sharing updates and fake smiles are not the most awaited moments of the day, especially during the third quarter of the mission when performance declines. Participants may quickly experience a high level of stress when the preparation fails to teach them the right coping-mechanisms.

In this context, life-threatening conditions are not controlled but almost promoted. Analogues seem to degenerate in a sort of “role-playing games” where the mission design, and thus its operational value, is not as critical as it used to be. In practice, an analogue represents an independent scenario that cannot be used as a starting point for simulating a sequence of studies embracing multiple missions, like on the International Space Station. Each analogue result is not reproducible because of the high number of factors, introducing a variability between missions alter the crew dynamics in an uncontrolled way. Most outcomes of research involving human subjects in analogue missions stand on their own. Comparing outcomes with either other ground missions or space missions is a convenience rather than a wise thing to do. Consequently, the scientific validity of a much of the research conducted in an analogue mission may become questionable or open to further interpretation if the study does not highlight information about safety and mission design.

Analogues seem to degenerate in a sort of “role-playing games” where the mission design, and thus its operational value, is not as critical as it used to be.

Moreover, safety guidelines developed for human spaceflights are not directly applicable or transferable due to the gaps in complexity dividing real crewed space missions from analogue missions, which can be either very simple or very complex. Additionally, analogue astronauts are participants with a broader range of performance, often not trained enough to maintain high performance over time. Hence, the underlying safety of these two types of missions is incompatible. These limitations contribute to diminishing the scientific impact of analogue missions, making them a passive contributor to human exploration of space but a crucial tool for keeping the public consent high.

Analogues that are run with the involvement of space agencies are more likely to benefit from a long history of lessons learned in human spaceflight and management of such activities. Examples of such missions are NASA’s NEEMO and HERA, as well as ESA’s CAVES and PANGAEA. These types of activities are astronaut training programs, although known as analogues. Here, the realism, or the fidelity, of a mission, is in all the three main aspects at multiple levels. Yet, the use of one of these facilities or procedures alone cannot guarantee to produce a high-fidelity mission. A mission is high-fidelity when all its features are designed to be as such.

Against this backdrop of challenges, a classification of analogues may help to identify the types of missions by looking at the fidelity level and other easily identifiable features. [1] In such a way, it would be easier to identify the types of human factors that are more likely to emerge from specific conditions and, consequently, to set the corresponding safety requirements. The intent is to simplify the description of the mission design, even when a mission has already ended. Missions will always have inevitable issues, and the classification would allow researchers to account for any tentative outcomes. Experts and space enthusiasts will never speak the same language, and the classification may act as a common platform for exchanging information, serving as a partial solution to the challenges mentioned above.

Analogues seem destined to evolve and will eventually shift into training scenarios for commercial astronauts. The dynamism we are witnessing is the result of multiple tentative to express new ways to apply science. The fragility of this business sector is an open door for international collaborations and an opportunity to strengthen global research efforts towards a unique goal, which is supporting human exploration of space. Future missions beyond low Earth orbit will be sustained by global efforts greater than those uniting us in facing the current global public health emergency. Analogues are a self-expression of individuals, not yet of societies or countries. The greatest challenge is to bring in these future scenarios the sense of community, which is now missing as the concept of humanity.


  1. Cinelli I. (2020) Short- and Long-Duration Mission Human Factors Requirements. In: Seedhouse E., Shayler D. (eds) Handbook of Life Support Systems for Spacecraft and Extraterrestrial Habitats. Springer, Cham.

Note: we are temporarily moderating all comments submitted to deal with a surge in spam.