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The self-replicating machine has high utility by virtue of its universal construction properties and its productive capacity for exponential growth. Their capacity is unrivalled. They can be deployed to the Moon to industrialize it using local in-situ resources in the short term to open up the solar system and thence deployed on interstellar spacecraft to explore the entire Galaxy by exploiting in-situ stellar system resources. Nevertheless, there are significant concerns regarding the inherent safety of self-replicating machines. We consider the general problem of runaway population growth in physical self-replicating machines to prevent the grey goo problem, the number of offspring spawned by self-replicating machines may be controlled at a genetic level. We adopt a biologically-inspired approach based on telomeres, DNA endcaps that are progressively shortened during cellular replication. This acts as a counter that imposes a limit to the number of replication cycles (Hayflick limit). By examining the biological process in detail, we can obtain some insights in implementing similar mechanisms in self-replicating machines. In particular, we find that counting mechanisms are vulnerable to cancerous runaway.

In the early 1980s, the Sagan-Tipler debate raged regarding the interpretation of the Fermi paradox but no clear winner emerged. Sagan favoured the existence of ETI on the basis of the Copernican principle and Tipler favoured the non-existence of ETI on the basis of the Occam's razor principle. Tipler's stance was an expansion of the similar but earlier Hart declaration. However, crucial to the Tipler argument was the role played by self-replicating interstellar robot probes. Any technologically capable species will develop self-replication technology as the most economical means of exploring space and the Galaxy as a whole with minimal investment. There is no evidence of such probes in our solar system including the asteroid belt, ergo, ETI do not exist. This is a powerful and cogent argument. Counter-arguments have been weak including Sagan's sociological explanations. We present a Copernican argument that ETI do not exist – humans are developing self-replication technology today. We are developing the ability to 3D print entire robotic machines from extraterrestrial resources including electric motors and electronics as part of a general in-situ resource utilization (ISRU) capability. We have 3D-printed electric motors which can be potentially leveraged from extraterrestrial material that should be available in every star system. From a similar range of materials, we have identified a means to 3D print neural network circuitry. From our industrial ecology, self-replicating machines and indeed universal constructors are feasible. We describe in some detail how a self-replicating interstellar spacecraft may be constricted from asteroidal resources. We describe technological signatures of the processing of asteroidal material (which is expected to be common to most star systems), and the excess production of certain types of clay and other detritus materials. Self-replication technology is under development and imminent – if humans are pursuing self-replication technology, then by the Copernican principle, so would any technologically savvy species elsewhere. There is no evidence that they have.

The search for extant microbial life will be a major focus of future astrobiology missions; however, no direct extant life detection instrumentation is included in current missions to Mars. In this study, we developed the semiautomated MicroLife detection platform that collects and processes environmental samples, detects biosignatures, and characterizes microbial activity. This platform is composed of a drill for sample collection, a redox dye colorimetric system for microbial metabolic activity detection and assessment (mMAMA [microfluidics Microbial Activity MicroAssay]), and a MinION sequencer for biosignature detection and characterization of microbial communities. The MicroLife platform was field-tested on White Glacier on Axel Heiberg Island in the Canadian high Arctic, with two extracted ice cores. The mMAMA successfully detected microbial metabolism from the ice cores within 1 day of incubation. The MinION sequencing of the ice cores and the positive mMAMA card identified a microbial community consistent with cold and oligotrophic environments. Furthermore, isolation and identification of microbial isolates from the mMAMA card corroborated the MinION sequencing. Together, these analyses support the MicroLife platform's efficacy in identifying microbes natively present in cryoenvironments and detecting their metabolic activity. Given our MicroLife platform's size and low energy requirements, it could be incorporated into a future landed platform or rovers for life detection. Key Words: Life detection-Automation-Drilling-MinION-mMAMA-Glaciers-CryoenvironmentsAstrobiology. Astrobiology 23, xxx-xxx.

We explore the limits of in situ resource utilization (ISRU) on the Moon to maximize living off the land by building lunar bases from in situ material. We adopt the philosophy of indigenous peoples who excelled in sustainability. We are interested in leveraging lunar resources to manufacture an entire lunar base in such a fashion that is fully sustainable and minimizes supplies required from Earth. A range of metals, ceramics and volatiles can be extracted from lunar minerals to support construction of a lunar base that include structure, piping and electrical distribution systems. To 3D print a lunar base, we must 3D print the load-bearing structure, electrical distribution system, water-based heating system, drinking water system, air system and orbital transport system from in situ resources. We also address the manufacture of the interior of the lunar base from local resources. The majority of systems constituting a lunar base can be manufactured from in situ resources.

The Moon Village and similar concepts are strongly reliant on in situ resource utilisation (ISRU). There is great interest in harvesting solar power using locally leveraged in situ resources as an essential facet of in situ infrastructure. Traditionally, silicon-based photovoltaic cells have been assumed, preferably manufactured in situ using a 3D printing rover, but there are major difficulties with such scenarios. Solar cells require pre-processing of regolith and solar cell manufacture. We present an alternative lunar resource leveraged-solar power production system on the Moon which can yield high conversion efficiencies – solar Fresnel lens-thermionic conversion. The thermionic vacuum tube is constructed from lunar-derived materials and NiFe asteroidal ores on the Moon. Given that the majority of energy required for ISRU is thermal, thermionic conversion exploits this energy source directly. Silicates such as anorthite can be treated with acid to yield alumina and silicic acid in solution from which pure silica can be precipitated. Pure silica when heated to high temperature yields fused silica glass which is transparent – fused silica glass may be employed to manufacture Fresnel lenses and/or mirrors. Both silica and alumina may be input to the Metalysis Fray Farthing Chen Cambridge electrolytic process to yield near pure Si and near pure Al, respectively.

Water vapor plumes emanating from the geyser vents at Enceladus’s south pole area invite the possibility of direct access to the subsurface liquid reservoir to acquire pristine biological material ...

The ice plumes emanating from the geyser vents at Enceladus’ south pole offer an enticing route for direct access to acquire pristine astrobiological samples. Unlike traditional landing scenarios where the location of the landing target is known a priori, we propose that one or more penetrators explore the plume environment via lateral maneuvers during the descent to Enceladus’ surface to infer the location of promising landing sites by autonomously measuring the plume ice/vapour concentration at multiple locations within the plume. This offers the prospect of targeting the vent sources of the plumes for direct access to subsurface material prior to its ejection. We examine four types of “viffing” (vector-in-forward flight) descent profiles and the impulsive velocity increment ( Δ V ) required for the lateral maneuvers: (i) a ballistic descent trajectory with a minimal Δ V cost represents the reference trajectory that implements no lateral search maneuvers; (ii) a planar descent with a decaying lateral oscillation which has an intermediate Δ V cost and a small search area; (iii) a nested series of decreasing sized box trajectories offering intermediate Δ V costs of varying degrees depending on the specific parameters; and, (iv) a quasi-spiral trajectory of decreasing radius which imposes the highest Δ V cost but with the largest lateral search area. Computations and simulations determined that the proposed viffing maneuvers are feasible and permit accurate targeting of Enceladian geyser vents at modest cost in Δ V . We also briefly assessed the problem of mapping the Enceladian plume during the descent, which will ultimately be necessary for viffing.

Mars exploration motivates the search for extraterrestrial life, the development of space technologies, and the design of human missions and habitations. Here, we seek new insights and pose unresolved questions relating to the natural history of Mars, habitability, robotic and human exploration, planetary protection, and the impacts on human society. Key observations and findings include:–high escape rates of early Mars' atmosphere, including loss of water, impact present-day habitability;–putative fossils on Mars will likely be ambiguous biomarkers for life;–microbial contamination resulting from human habitation is unavoidable; and–based on Mars' current planetary protection category, robotic payload(s) should characterize the local martian environment for any life-forms prior to human habitation.Some of the outstanding questions are:–which interpretation of the hemispheric dichotomy of the planet is correct;–to what degree did deep-penetrating faults transport subsurface liquids to Mars' surface;–in what abundance are carbonates formed by atmospheric processes;–what properties of martian meteorites could be used to constrain their source locations;–the origin(s) of organic macromolecules;–was/is Mars inhabited;–how can missions designed to uncover microbial activity in the subsurface eliminate potential false positives caused by microbial contaminants from Earth;–how can we ensure that humans and microbes form a stable and benign biosphere; and–should humans relate to putative extraterrestrial life from a biocentric viewpoint (preservation of all biology), or anthropocentric viewpoint of expanding habitation of space?Studies of Mars' evolution can shed light on the habitability of extrasolar planets. In addition, Mars exploration can drive future policy developments and confirm (or put into question) the feasibility and/or extent of human habitability of space.

Self-replication is the de facto hallmark of life and has thus far eluded efforts to mimic it in physical engineered systems. According to the John von Neumann self-replication model, there are four major components – (i) a physical instantiation of a program of instructions to build the self-replicator (DNA), (ii) a mechanism for copying those instructions (DNA polymerase), (iii) a controller to interpret those instructions into a set of physical procedures (proteins), and (iv) a means to physically construct the self-replicator (ribosomes). The first and latter two parts constitute a universal Turing machine and universal constructing machine respectively. It is these three parts, in particular, with which we are concerned. The most important constraint is in physical closure which requires a: (i) minimum materials inventory; (ii) minimal set of chemical processes; (iii) minimum set of component part types; (iv) minimal set of manufacturing methods; (v) minimal assembly requirements. This aids in the requirements for energy and information closure. We have identified (i) a minimal list of functional materials (demandite) to build the self-replicator; (ii) a single electrochemical process to extract the metals supplemented with a small set of mineral pre-processing methods; (iii) a set of two fundamental components that are key – the electric motor (which may be configured into any kinematic machine, i.e. universal constructor) and vacuum tube (active component of Turing-complete neural electronics, i.e. universal computer); (iv) a set of additive manufacturing techniques to 3D print all parts including electric motors and vacuum tubes.

We are familiar with the notion of carbon-based life forms, but are there alternatives? In this article, I describe an approach to build a living machine from engineering materials that lacks any biochemistry but uses engineering methods to live. In devising this self-replicating machine, we explore broader scientific notions of what life might be and how it might be realized, rather than being limited to what it is on Earth.

With the recent proliferation of unmanned aerial vehicles for geophysical surveying, a novel opportunity exists to develop unmanned ground vehicles in parallel. This contribution features a study to integrate the Husky A200 robotic development platform with a GSMP 35U magnetometer that has recently been developed for the unmanned aerial vehicle market. Methods to identify and reduce the impact of magnetically noisy components on the unmanned ground vehicle platforms are discussed. The noise generated by the platform in laboratory and gentle field conditions, estimated using the fourth difference method for a magnetometer–vehicle separation distance of 121 cm and rotation of the chassis wheels at full speed (1 m/s), is ±1.97 nT. The integrated unmanned ground vehicle was used to conduct two robotic magnetic surveys to map cultural targets and natural variations of the magnetic field. In realistic field conditions, at a full speed of 1 m/s, the unmanned ground vehicle measured total magnetic intensity over a range of 1730 nT at 0.1 m spatial resolution with a productivity of 2651 line metres per hour.

Recent work in developing self-replicating machines has approached the problem as an engineering problem, using engineering materials and methods to implement an engineering analogue of a hitherto uniquely biological function. The question is – can anything be learned that might be relevant to an astrobiological context in which the problem is to determine the general form of biology independent of the Earth. Compared with other non-terrestrial biology disciplines, engineered life is more demanding. Engineering a self-replicating machine tackles real environments unlike artificial life which avoids the problem of physical instantiation altogether by examining software models. Engineering a self-replicating machine is also more demanding than synthetic biology as no library of functional components exists. Everything must be constructedde novo. Biological systems already have the capacity to self-replicate but no engineered machine has yet been constructed with the same ability – this is our primary goal. On the basis of the von Neumann analysis of self-replication, self-replication is a by-product of universal construction capability – a universal constructor is a machine that can construct anything (in a functional sense) given the appropriate instructions (DNA/RNA), energy (ATP) and materials (food). In the biological cell, the universal construction mechanism is the ribosome. The ribosome is a biological assembly line for constructing proteins while DNA constitutes a design specification. For a photoautotroph, the energy source is ambient and the food is inorganic. We submit that engineering a self-replicating machine opens up new areas of astrobiology to be explored in the limits of life.

The detection of atmospheric methane on Mars implies an active methane source. This introduces the possibility of a biotic source with the implied need to determine whether the methane is indeed biotic in nature or geologically generated. There is a clear need for robotic algorithms which are capable of manoeuvring a rover through a methane plume on Mars to locate its source. We explore aspects of Mars methane plume modelling to reveal complex dynamics characterized by advection and diffusion. A statistical analysis of the plume model has been performed and compared to analyses of terrestrial plume models. Finally, we consider a robotic search strategy to find a methane plume source. We find that gradient-based techniques are ineffective, but that more sophisticated model-based search strategies are unlikely to be available in near-term rover missions.

Robotic astrobiology involves the remote projection of intelligent capabilities to planetary missions in the search for life, preferably with human-level intelligence. Planetary rovers would be true human surrogates capable of sophisticated decision-making to enhance their scientific productivity. We explore several key aspects of this capability: (i) visual texture analysis of rocks to enable their geological classification and so, astrobiological potential; (ii) serendipitous target acquisition whilst on the move; (iii) continuous extraction of regolith properties, including water ice whilst on the move; and (iv) deep learning-capable Bayesian net expert systems. Individually, these capabilities will provide enhanced scientific return for astrobiology missions, but together, they will provide full autonomous science capability.

Geomagnetic data gathering by micro-rovers is gaining momentum both for future planetary exploration missions and for terrestrial applications in extreme environments. This paper presents research into the integration of a planetary micro-rover with a potassium total-field magnetometer. The 40 kg Kapvik micro-rover is an ideal platform due to an aluminium construction and a rocker-bogie mobility system, which provides good manoeuvrability and terrainability. A light-weight GSMP 35U (uninhabited aerial vehicle) magnetometer, comprised of a 0.65 kg sensor and 0.63 kg electronics module, was mounted to the chassis via a custom 1.21 m composite boom. The boom dimensions were optimized to be an effective compromise between noise mitigation and mechanical practicality. An analysis using the fourth difference method was performed estimating the magnetic noise envelope at ±0.03 nT at 10 Hz sampling frequency from the integrated systems during robotic operations. A robotic magnetic survey captured the total magnetic intensity along three parallel 40 m long lines and a perpendicular 15 m long tie line over the course of 3.75 h. The total magnetic intensity data were corrected for diurnal variations, levelled by linear interpolation of tie-line intersection points, corrected for a regional gradient, and then interpolated using Delaunay triangulation to lead a residual magnetic intensity map. This map exhibited an anomalous linear feature corresponding to a magnetic dipole 650 nT in amplitude. This feature coincides with a storm sewer buried approximately 2 m in the subsurface. This work provides benchmark methodologies and data to guide future integration of magnetometers on board planetary micro-rovers.