Stephen J. Hoffman

Human exploration of Mars, Design Reference Architecture 5.0

This paper provides a summary of the 2007 Mars Design Reference Architecture 5.0 (DRA 5.0) [1], which is the latest in a series of NASA Mars reference missions. It provides a vision of one potential approach to human Mars exploration, including how Constellation systems could be used. The strategy and example implementation concepts that are described here should not be viewed as constituting a formal plan for the human exploration of Mars, but rather provide a common framework for future planning of systems concepts, technology development, and operational testing as well as potential Mars robotic missions, research that is conducted on the International Space Station, and future potential lunar exploration missions. This summary of the Mars DRA 5.0 provides an overview of the overall mission approach, surface strategy and exploration goals, as well as the key systems and challenges for the first three concepts for human missions to Mars.1,2

Transportation-driven mars surface operations supporting an evolvable mars campaign

This paper describes the results of a study evaluating options for supporting a series of human missions to a single Mars surface destination. In this scenario the infrastructure emplaced during previous visits to this site is leveraged in following missions. The goal of this single site approach to Mars surface infrastructure is to enable “Steady State” operations by at least 4 crew for up to 500 sols at this site. These characteristics, along with the transportation system used to deliver crew and equipment to and from Mars, are collectively known as the Evolvable Mars Campaign (EMC). Information in this paper is presented in the sequence in which it was accomplished. First, a logical buildup sequence of surface infrastructure was developed to achieve the desired “Steady State” operations on the Mars surface. This was based on a concept of operations that met objectives of the EMC. Second, infrastructure capabilities were identified to carry out this concept of operations. Third, systems (in the form of conceptual elements) were identified to provide these capabilities. This included top-level mass, power and volume estimates for these elements. Fourth, the results were then used in analyses to evaluate three options (18t, 27t, and 40t landed mass) of Mars Lander delivery capability to the surface. Finally, Mars arrival mass estimates were generated based upon the entry, descent, and landing requirements for inclusion in separate assessments of in-space transportation capabilities for the EMC.

Human Mars landing site and impacts on Mars surface operations

This paper describes NASAs initial steps for identifying and evaluating candidate Exploration Zones (EZs) and Regions of Interests (ROIs) for the first human crews that will explore the surface of Mars. NASAs current effort to define the exploration of this planet by human crews, known as the Evolvable Mars Campaign (EMC), provides the context in which these EZs and ROIs are being considered. The EMC spans all aspects of a human Mars mission including launch from Earth, transit to and from Mars, and operations on the surface of Mars. An EZ is a collection of ROIs located within approximately 100 kilometers of a centralized landing site. ROIs are areas relevant for scientific investigation and/or development/maturation of capabilities and resources necessary for a sustainable human presence. The EZ also contains one or more landing sites and a habitation site that will be used by multiple human crews during missions to explore and utilize the ROIs within the EZ. With the EMC as a conceptual basis, the EZ model has been refined to a point where specific site selection criteria for scientific exploration and in situ resource utilization can be defined. In 2015 these criteria were distributed to the planetary sciences community and the in situ resource utilization and civil engineering communities as part of a call for EZ proposals. The resulting “First Landing Site/Exploration Zone Workshop for Human Missions to the Surface of Mars” was held in October 2015 during which 47 proposals for EZs and ROIs were presented and discussed. Proposed locations spanned all longitudes and all allowable latitudes (+/-50 degrees). Proposed justification for selecting one of these EZs also spanned a significant portion of the scientific and resource criteria provided to the community. Several important findings resulted from this Workshop including: (a) a strong consensus that, at a scale of 100 km (radius), multiple places on Mars exist that have both sufficient scientific interest to sustain multiple crews of exploring astronauts, AND potential resource deposits for ISRU indicating the current EZ definition is viable and should be retained for now, (b) new data types (needed for more definitive analysis of EZs) argued strongly for a new orbiter mission, and possibly one or more surface missions, to obtain these data, (c) a general consensus that this Workshop was an excellent start to identifying a place where future human missions to Mars can productively explore this planet and learn to live and work there for the long term. Building on these findings, HEOMD and SMD are: (a) refining the EZ selection criteria and overall selection process to improve on lessons learned from the first EZ workshop, (b) using these proposed locations to develop “reference EZs” for assessment purposes (primarily engineering assessments), (c) gathering data and conducting analyses to better understanding the different potential sources for water, including the ease of extraction and purification, and (d) assessing trends in additional data that are needed to better characterize EZs proposed at the workshop and how these data needs impact the design and operation of future robotic Mars missions.

Mars as a Destination in a Capability-Driven Framework

This paper describes NASA s current plans for the exploration of Mars by human crews within NASA s Capability-Driven Framework (CDF). The CDF describes an approach for progressively extending human explorers farther into the Solar System for longer periods of time as allowed by developments in technology and spacecraft systems. Within this framework, Mars defines the most challenging objective currently envisioned for human spaceflight. The paper first describes the CDF and potential destinations being considered within this framework. For destinations relevant to the exploration of Mars, this includes both the Martian surface and the two moons of Mars. This is followed by a brief review of our evolving understanding of Mars to provide the context for the specific objectives set for human exploration crews. This includes results from robotic missions and goals set for future Martian exploration by NASAs community-based forum, the Mars Exploration Program Analysis Group (MEPAG) and the MEPAG-sponsored Human Exploration of Mars - Science Analysis Group (HEM-SAG). The paper then reviews options available for human crews to reach Mars and return to Earth. This includes a discussion of the rationale used to select from among these options for envisioned Mars exploration missions. The paper then concludes with a description of technological and operational challenges that still face NASA in order to be able to achieve the exploration goals for Mars within the CDF.

Mars surface habitability options

This paper reports on current habitability concepts for an Evolvable Mars Campaign (EMC) prepared by the NASA Human Spaceflight Architecture Team (HAT). For many years NASA has investigated alternative human Mars missions, examining different mission objectives, trajectories, vehicles, and technologies; the combinations of which have been referred to as reference missions or architectures. At the highest levels, decisions regarding the timing and objectives for a human mission to Mars continue to evolve while at the lowest levels, applicable technologies continue to advance. This results in an on-going need for assessments of alternative system designs such as the habitat, a significant element in any human Mars mission scenario, to provide meaningful design sensitivity characterizations to assist decision-makers regarding timing, objectives, and technologies. As a subset of the Evolvable Mars Campaign activities, the habitability team builds upon results from past studies and recommends options for Mars surface habitability compatible with updated technologies.

Mars surface systems common capabilities and challenges for human missions

This paper describes the current status of common systems and operations as they are applied to actual locations on Mars that are representative of Exploration Zones (EZ) - NASAs term for candidate locations where humans could land, live and work on the martian surface. Given NASAs current concepts for human missions to Mars, an EZ is a collection of Regions of Interest (ROIs) located within approximately 100 kilometers of a centralized landing site. ROIs are areas that are relevant for scientific investigation and/or development/maturation of capabilities and resources necessary for a sustainable human presence. An EZ also contains a habitation site that will be used by multiple human crews during missions to explore and utilize the ROIs within the EZ. The Evolvable Mars Campaign (EMC), a description of NASAs current approach to these human Mars missions, assumes that a single EZ will be identified within which NASA will establish a substantial and durable surface infrastructure that will be used by multiple human crews. With this assumption it becomes important to evaluate the current suite of surface systems and operations being evaluated for the EMC are likely to perform at a variety of proposed EZ locations. Four locations identified in MEPAGs Human Exploration of Mars Science Analysis Group (HEM-SAG) report are used in this paper as representative of candidate EZs that will emerge from the selection process that NASA has initiated. A field station site plan is developed for each of these four HEM-SAG sites. Several important findings have emerged from these preliminary assessments: (1) at each of the four HEM-SAG sites there was a 10 km × 10 km area at or near the proposed landing site within which it is reasonable to set up a landing site and habitation site consistent with the needs of a Mars surface field station, (2) at each of these 10 km × 10 km sites it is possible to set up a central location for a common power system and locate the landing and habitation zones in a radial configuration around this power system. However, additional analysis will be needed to look at alternative site layouts that could “better” utilize the natural features of a particular site, and (3) with the possible exception of a climb to the top of Arsia Mons, all of the proposed traverses appear to be feasible for the small pressurized rover currently envisioned for these surface missions. Based on these findings our recommendation is to continue (a) the selection process of EZs used in the recent workshop that will lead to one or more optimum surface locations, (b) continue to evaluate the minimum functionality required to establish a surface field station within the center of an EZ, and (c) identify those demonstrations that could be conducted at the Mars surface field station utilizing local resources to gradually establish the Earth independence necessary to sustain crews for long periods of time.

Traverse Planning Experiments for Future Planetary Surface Exploration

This paper describes the results of a recent (July-August 2010 and July 2011) planetary surface traverse planning experiment. The purpose of this experiment was to gather data relevant to robotically repositioning surface assets used for planetary surface exploration. This is a scenario currently being considered for future human exploration missions to the Moon and Mars. The specific scenario selected was a robotic traverse on the lunar surface from an outpost at Shackleton Crater to the Malapert Massif. As these are exploration scenarios, the route will not have been previously traversed and the only pre-traverse data sets available will be remote (orbital) observations. Devon Island was selected as an analog location where a traverse route of significant length could be planned and then traveled. During the first half of 2010, a team of engineers and scientists who had never been to Devon Island used remote sensing data comparable to that which is likely to be available for the Malapert region (eg., 2-meter/pixel imagery, 10-meter interval topographic maps and associated digital elevation models, etc.) to plan a 17-kilometer (km) traverse. Surface-level imagery data was then gathered on-site that was provided to the planning team. This team then assessed whether the route was actually traversable or not. Lessons learned during the 2010 experiment were then used in a second experiment in 2011 for which a much longer traverse (85 km) was planned and additional surface-level imagery different from that gathered in 2010 was obtained for a comparative analysis. This paper will describe the route planning techniques used, the data sets available to the route planners and the lessons learned from the two traverses planned and carried out on Devon Island.

Human Exploration of Asteroids, the Moon, and Mars Using Robotic Arm-Equipped Pressurized Vehicles

During the 2011 summer field campaign of the NASA Haughton-Mars Project at the Haughton impact crater site on Devon Island in the high Arctic, field tests were conducted of the use of a robotic arm system integrated to Humvees serving as analog pressurized vehicles for the human exploration of near-Earth asteroids, the Moon, and Mars. The goal of these field tests was to begin assessing how field geology, including sample acquisition, might in some cases be conducted effectively from the confines of a pressurized vehicle (in intra-vehicular or IVA mode) without the crew having to always go out on EVA. Preliminary findings suggest that, particularly at sites where rocks and soils available for sampling occur mostly as loose rubble or float (as with planetary regoliths), the use of a robotic arm can allow efficient collection and characterization of high quality samples. An important implication of the finding for future space exploration architecture development, if confirmed through further field tests, is that the number and frequency of EVAs needed for sample acquisition during planetary vehicular traverses might be reduced from current assumptions. Wear and tear on EVA suit and suit-port systems, mission operations complexity, crew exposure to space radiation, and planetary protection concerns, might all be significantly reduced if robotic-arm assisted sample acquisition in IVA mode became available as an effective option for science operations.

Operational considerations for a crewed nuclear powered space transportation vehicle

Applying nuclear propulsion technology to human space travel will require new approaches to conducting human operations in space. Due to the remoteness of these types of missions, the crew and their vehicle must be capable of operating independent from Earth‐based support. This paper discusses current operational studies which address methods for performing these types of remote and autonomous missions. Methods of managing the hazards to humans who will operate these high‐energy nuclear‐powered transportation vehicles also is reviewed. Crew training for both normal and contingency operations is considered. Options are evaluated on how best to train crews to operate and maintain the systems associated with a nuclear engine. Methods of maintaining crew proficiency during the long months of space travel are discussed. Vehicle health maintenance also will be a primary concern during these long missions. A discussion is presented on how on‐board vehicle health maintenance systems will monitor system trends, id...