Terrestrial analogue environments are places on Earth that present geological or environmental conditions that are similar to those found on an extraterrestrial body. Analogue environments serve four functions: (1)
Les environnements terrestres analogues sont des endroits sur Terre qui possèdent des conditions géologiques ou environnementales semblables à celles d’un corps extraterrestre. L’étude des environnements analogues permet : (1) de mieux connaître les processus planétaires terrestres et extraterrestres ; (2) de tester des technologies, des méthodologies et des protocoles ; (3) de former du personnel hautement qualifié, ainsi que des équipes scientifiques et opérationnelles ; (4) d’attirer l’attention du public, des agences spatiales, des médias et des enseignants. Les études dites analogues permettent également de développer et de tester des techniques de détection de biosignatures. Les
Terrestrial analogue environments are places on Earth with geological or environmental conditions that are similar to those that exist on an extraterrestrial body. So-called “analogue studies” are essential to planetary exploration because they help us understand the workings of certain processes on Earth and thus to interpret and validate the data received from orbiter or surface missions to the Moon, Mars, or beyond. Analogue studies are also critical in understanding scientific and technological requirements and strategies for astrobiology-related robotic or human exploration missions. Notably, these studies can provide operational tests of instruments and technologies under relevant environmental conditions. In addition, these sites can allow validation of the ability of space instruments to function properly under conditions difficult to replicate in the laboratory and that approach the environmental or geological complexity and heterogeneity of the eventual target. Through analogue studies, technologies for astrobiology can be developed affordably and practically, thus reducing overall costs and risks associated with the development process. In this paper, examples of analogue environments and their functions are described. In addition, examples of validation of astrobiology technologies and operations in analogue environments are summarized.
Terrestrial analogue environments are defined as places on Earth that present one or more sets of geological or environmental conditions similar to those found on an extraterrestrial body, current or past
The term
In the widest sense, the term
Generally, analogue environments serve four basic functions
These functions are described in more detail below.
It is widely acknowledged that analogue environments are critical to the understanding of extraterrestrial processes. Analogue studies allow us to learn about terrestrial processes and, by extrapolation, processes on extraterrestrial bodies. They also enable us to learn about the limits of both physical and biological processes on Earth, thus defining zones of habitability and providing clues to where life could be present, or may have developed elsewhere
Terrestrial analogue studies are especially critical in the ongoing transition from global mapping missions to missions (especially with respect to Mars) focusing on detailed analyses at the regional and outcrop scale
Analogue studies are essential to the testing and validation of space technologies and science instruments, as well as their successful operation
Analogue studies can also be used to test the wear on hardware in realistic operating conditions
Analogue environments are particularly suitable for demonstrating systems integration (e.g., a rover with a mounted drill system) or system-of-system capabilities where several technologies are required to function together. Integrating robotic science experiments with a high level of realism and integration can provide significant insights to component technology capabilities and operational limitations, but also give serendipitous findings about operational strategies and science return
In addition to various instruments, planetary surface operations, both robotic and human, can be developed and tested in analogue environments
Field tests and deployments provide valuable lessons-learned opportunities for design improvements, technology needs, and critical operational experience
Science investigations and technology validation in analogue environments can serve to train various personnel, from students and educators, to science and mission team members, and ultimately, to astronauts. In fact, various field campaigns featured prominently in the training of Apollo astronauts in the 1960s and early 1970s. Analogue studies provide opportunities for scientists, engineers, educators and students to contribute to the design and planning of missions, by characterizing design and performance of technologies, science approach, and operational concepts, while gaining the operational (hands-on) experience needed for future missions.
Training in tactical operations and the day-to-day (or sol-to-sol) decision-making process can be accomplished through the use of off-site simulated science operations centers (i.e., “backrooms”)
Studies in analogue environments are naturally conducive to educational and public outreach (EPO) activities as they easily capture people's attention because they often take place in remote, exotic locations, and they are directly related to planetary exploration and space missions. EPO activities provide opportunities for the public to participate directly in a space program
More specifically for astrobiology, analogue studies enable the development and validation of biosignatures and detection techniques
In 2005, following recommendations from the scientific community, the Canadian Space Agency (CSA) launched the Canadian Analogue Research Network (CARN). This program includes funding for infrastructure and logistical support at three competitively-selected sites (Haughton-Mars Project Research Station; McGill Arctic Research Station; Pavilion Lake Research Project). In addition, researchers compete annually for research grants in order to perform science investigations or technology validations at the three main CARN sites or at any other analogue field site in Canada, or abroad. CARN addresses requirements for coordination among many field activities and focuses the community on a few field sites, thus helping to build data sets and supporting information
One of the goals of the CARN program is to foster international collaboration. CARN grants have been used to study sites abroad and international collaborators can also receive limited funding to work at Canadian sites with a Canadian-based principal investigator. Related activities include development of a missions database, data archive and web-based geographical information systems (WebGISs) of CARN sites
NASA's Astrobiology Science and Technology for Exploring Planets (ASTEP) is a science-driven exploration program that supports science investigations focusing on astrobiological research in terrestrial analogue environments in order to improve knowledge of the limits and constraints on life in extreme environments. ASTEP was conceived to help produce new science and operational/technological capabilities that will enable further planetary exploration. The program aims to decrease the risks of planetary exploration through technology development (i.e., sample acquisition and handling techniques, remote sample manipulation, mobile science systems including planetary rovers, techniques for autonomous operations, and self-contained deployment systems). ASTEP field campaigns
An
Analogue missions are essentially Earth-based expeditions with characteristics that are analogous to missions on the Moon or Mars. Analogue missions investigate solutions to questions related to science definition and requirements of surface missions, test and refine operational concepts and task efficiency; test operations tools; and test design, configuration, and functionality of hardware/software. While analogue and laboratory studies may address what are viable biosignatures and what are the limits of life on Earth (i.e., what is a
NASA has recently announced an Analogue Missions opportunity, partly in response to the U.S. Congress (Public Law 109-155, section 504), which explicitly instructs NASA to establish ground based analog capabilities in remote locations in the United States in order to develop “lunar operations, life support, and in-situ resource utilization experience and capabilities”.
The HPMRS is an international multidisciplinary field research project focusing on the Haughton Impact Structure and its surroundings on Devon Island in the Canadian High Arctic (
In light of NASA's current plan for the exploration of Mars, which has been to
The AMASE program enables the development and validation of scientific instruments in analogue sites in Svalbard (Norway), including instruments that will be aboard the validate the robustness of portable life detection instruments; analyze traces of life in Mars analogue environments; develop protocols to reduce contamination of instruments and samples
The X-ray diffraction/fluorescence (XRD/XRF) instrument CheMin
In addition, the Sample Analysis at Mars (SAM) instrument, also selected for MSL, was tested in parallel, in some cases using the same samples as those analysed by CheMin
The drainage basin of the
The Mars Astrobiology Research and Testing Experiment (MARTE) project was a 3-year NASA-funded project that sought to develop the science and technologies necessary for drilling and sample manipulation for future missions to Mars
NASA's Field Integrated Design and Operations (FIDO) rover is an advanced mobile platform and research prototype for Mars surface missions
In 2002, a 10-day blind test focused on teaching the science team how to remotely conduct field geology using a rover, rather than to test the rover hardware itself. The rover was sent to a distant, undisclosed desert location, while the science team planned the operations and sent commands from a distant location (Jet Propulsion Lab, Pasadena, CA). Mission success criteria, which included going to at least two different locations, making extensive measurements, driving 200 meters (656 feet), and digging a soil trench with one of the rover's wheels, were all met. The latter exercise proved fruitful as the MER
The first detection of extra-terrestrial biosignatures will raise two important questions: is it a biosignature (i.e., has it been produced by life rather than geochemical processes); and is it real (i.e., are we confidant of the instrument's detection limits given the contamination along the overall pathway of sample acquisition, handling, processing and analysis)? Both of these questions can benefit greatly from extensive analogue studies as shown herein.
The National Research Council (U.S.A.) recommends that terrestrial analogue studies “should continue to be a fundamental aspect of Mars astrobiological research”. Continued support of studies in analogue environments is therefore required. Scientific ground-truth measurements are essential for validating current flight instrumentation and for the development of advanced instrumentation and technologies for life-detection missions in the coming years
Analogue studies will also be critical for sample return missions, whereby a complex interplay of technologies will be put to use in a very carefully pre-selected site or series of sites on Mars. Analogue studies will be essential for selecting appropriate target sites, sampling and site characterization strategies, and overall mission operations, as well as for developing the multitude of technologies and systems for such a mission.
Recently, an International Analogue Network (IAN) has been proposed
Vicky Hipkin and Marianne Mader (Canadian Space Agency) are thanked for their valuable input and for sharing ideas. Muriel Gargaud is also thanked for her dedication and commitment to the ExoBio courses and related activities.
An example of a terrestrial analogue environment of Mars relevant to astrobiology: the Haughton Impact Structure, Devon Island, Canadian High Arctic. View of the
Fig. 1. Un exemple d’un environnement analogue terrestre de Mars, important pour l’astrobiologie : le cratère d’impact Haughton, île Devon, Arctique canadien. Vue de la
Astrobiology-related analogue environments at the Haughton Impact Crater, Devon Island, Canada: a: impact breccias (grey, distance) and post-impact, paleolacustrine sediments (beige-brown, foreground); b: sulfide coating from impact-induced hydrothermal systems; c: microbial mats from a dried pond.
Fig. 2. Environnements analogues d’intérêt astrobiologique, situés dans le cratère d’impact Haughton, île Devon, Canada : a : brèches d’impact (gris ; arrière-plan) et sédiments paléolacustres intra-cratère (beige-brun ; premier plan) ; b : couche de dépôts de sulfures hydrothermaux induite par impact ; c : tapis microbiens provenant d’un étang séché.
Examples of analogue sites to Mars featuring astrobiology research and development activities.
Tableau 1 Exemples de sites analogues de Mars comprenant des activités de recherche et de développement en astrobiologie.