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Common Power and Energy Storage Solutions to Support Lunar and Mars Surface Exploration Missions

Future human exploration missions on the moon and Mars will require a new generation of power sources to sustain crew members and leverage in-situ resources. Long-duration human missions to the lunar and Martian surface will likely include large-scale landers, crew habitats, pressurized rovers, and in-situ propellant production plants. The power demands for these surface elements, whether on the moon or Mars, will be similar starting with robotic precursor missions in the multi-kilowatt range scaling to 10s of kilowatts as the crew presence expands and local propellant production is established. While the power requirements may be similar, the vastly different environments on the two surfaces present unique challenges for power generation and storage systems. Candidate technologies to satisfy the surface power needs include deployable solar arrays, regenerative fuel cells, and small fission reactors. This paper presents strategies for power system architectures with elements that can be used on the moon and are extensible to Mars with features that make them resilient to either environment.

Mason, Lee↗

Maintenance-optimized Modular Robotic Concepts for Planetary Surface ISRU Excavators

Modular robotic concepts are identified and evaluatedover the design and operations/maintenance lifecycle forautonomous Lunar, Mars, and partial gravity planetary surfaceexcavation and in-situ earthworks equipment. In-Situ ResourceUtilization (ISRU) is the exploitation of available resources at thesite of a landed spacecraft on the surface of another planetary body.It is intended that this ISRU excavator concept be capable ofmaterial extraction from native regolith, and will be able to operatein a variety of planetary surface environments after initial shakedownon the moon. Using heritage from highly multi-functional,reconfigurable robotic systems like the All-Terrain Hex-LimbedExtra-Terrestrial Explorer (ATHLETE), Regolith AdvancedSurface Systems Operations Robot (RASSOR), and Marsexploration rovers, we propose a flexible maintenance-optimizedmobility platform concept with quick-connect/disconnect featuresfor robotically swappable excavation implements. Dust toleranttorque transmission, power & data docking, thermal fluidconnectors, and modular avionics and instrumentation will allow forautonomous swapping of tools, replacement of spares, and longtermmaintenance of robotic excavators. The architecture includesmodular tools for conventional excavate / scoop / haul / dump /process functions of a terrestrial mining operation on Earth, but alsowill have the capability to operate and robotically maintain itselfwithout human intervention. The concepts described in this studywill provide a suite of technologies, configurations, and operationsready for inclusion into a final flight-ready excavator system.

Schuler, Jason↗

Environmental Control and Life Support (ECLS) System Options for Mars Transit and Mars Surface Missions

The NASA led Artemis campaign will take humanity back to the Moon and serve as an analog for continued deep space exploration to Mars. Artemis utilizes crewed vehicles and habitats on both the Lunar surface and in Lunar orbit. The exploration of the Lunar surface and buildup of a basecamp is meant to be a “Mars forward” approach to testing and refining new technologies and techniques for living and working far outside of Low Earth Orbit (LEO) and preparing for future Mars missions. The Lunar Surface Habitat is planned as a primary element for long duration crew habitation on the Moon and will be the primary testbed for ECLS system hardware in a partial gravity environment. The Mars Transit Habitat will be the crew vehicle for the roundtrip from Earth to Mars and spend a significant amount of time docked to the Gateway outfitting and testing its systems prior to making the first Mars mission transit. The Mars Transit Habitat will utilize closed loop ECLS system technologies while a Mars Surface Habitat could use either open loop, closed loop, or a mix of both. Better understanding the needs of both these system architectures operating for extended periods in the Lunar environment and outside LEO will help to establish the ECLS system architecture for the future Mars surface mission. There are many aspects to consider such as length of crew stay, level of autonomy and dormancy between crewed missions, power requirements, system mass, and overall system reliability and maintainability. Other considerations will include Mars gravity vs. Lunar gravity, Mars atmospheric pressure vs. hard vacuum, and possible use of in-situ resource utilization.

ECLSS↗

Environmental Control and Life Support (ECLS) System Options for Mars Transit and Mars Surface Missions

The NASA led Artemis campaign will take humanity back to the Moon and serve as an analog for continued deep space exploration to Mars. Artemis utilizes crewed vehicles and habitats on both the Lunar surface and in Lunar orbit. The exploration of the Lunar surface and buildup of a basecamp is meant to be a “Mars forward” approach to testing and refining new technologies and techniques for living and working far outside of Low Earth Orbit (LEO) and preparing for future Mars missions. The Lunar Surface Habitat is planned as a primary element for long duration crew habitation on the Moon and will be the primary testbed for ECLS system hardware in a partial gravity environment. The Mars Transit Habitat will be the crew vehicle for the roundtrip from Earth to Mars and spend a significant amount of time docked to the Gateway outfitting and testing its systems prior to making the first Mars mission transit. The Mars Transit Habitat will utilize closed loop ECLS system technologies while a Mars Surface Habitat could use either open loop, closed loop, or a mix of both. Better understanding the needs of both these system architectures operating for extended periods in the Lunar environment and outside LEO will help to establish the ECLS system architecture for the future Mars surface mission. There are many aspects to consider such as length of crew stay, level of autonomy and dormancy between crewed missions, power requirements, system mass, and overall system reliability and maintainability. Other considerations will include Mars gravity vs. Lunar gravity, Mars atmospheric pressure vs. hard vacuum, and possible use of in-situ resource utilization.

ECLSS↗

Cis-Lunar Base Camp

Historically, when mounting expeditions into uncharted territories, explorers have established strategically positioned base camps to pre-position required equipment and consumables. These base camps are secure, safe positions from which expeditions can depart when conditions are favorable, at which technology and operations can be tested and validated, and facilitate timely access to more robust facilities in the event of an emergency. For human exploration missions into deep space, cis-lunar space is well suited to serve as such a base camp. The outer regions of cis-lunar space, such as the Earth-Moon Lagrange points, lie near the edge of Earth s gravity well, allowing equipment and consumables to be aggregated with easy access to deep space and to the lunar surface, as well as more distant destinations, such as near-Earth Asteroids (NEAs) and Mars and its moons. Several approaches to utilizing a cis-lunar base camp for sustainable human exploration, as well as some possible future applications are identified. The primary objective of the analysis presented in this paper is to identify options, show the macro trends, and provide information that can be used as a basis for more detailed mission development. Compared within are the high-level performance and cost of 15 preliminary cis-lunar exploration campaigns that establish the capability to conduct crewed missions of up to one year in duration, and then aggregate mass in cis-lunar space to facilitate an expedition from Cis-Lunar Base Camp. Launch vehicles, chemical propulsion stages, and electric propulsion stages are discussed and parametric sizing values are used to create architectures of in-space transportation elements that extend the existing in-space supply chain to cis-lunar space. The transportation options to cis-lunar space assessed vary in efficiency by almost 50%; from 0.16 to 0.68 kg of cargo in cis-lunar space for every kilogram of mass in Low Earth Orbit (LEO). For the 15 cases, 5-year campaign costs vary by only 15% from 0.36 to 0.51 on a normalized scale across all campaigns. Thus the development and first flight costs of assessed transportation options are similar. However, the cost of those options per flight beyond the initial operational capability varies by 70% from 0.3 to 1.0 on a normalized scale. The 10-year campaigns assessed begin to show the effect of this large range of cost beyond initial operational capability as they vary approximately 25% with values from 0.75 to 1.0 on the normalized campaign scale. Therefore, it is important to understand both the cost of implementation and first use as well as long term utilization. Finally, minimizing long term recurring costs is critical to the affordability of future human space exploration missions. Finally minimizing long term recurring costs is critical to the affordability of future human space exploration missions.

Merrill, Raymond G.↗

Mars Exploration Architecture

The architecture of NASA's program of robotic Mars exploration missions received an intense scrutiny during the summer months of 1998. We present here the results of that scrutiny, and describe a list of Mars exploration missions which are now being proposed by the nation's space agency. The heart of the new program architecture consists of missions which will return samples of Martian rocks and soil back to Earth for analysis. A primary scientific goal for these missions is to understand Mars as a possible abode of past or present life. The current level of sophistication for detecting markers of biological processes and fossil or extant life forms is much higher in Earth-based laboratories than possible with remotely deployed instrumentation, and will remain so for at least the next decade. Hence, bringing Martian samples back to Earth is considered the best way to search for the desired evidence. A Mars sample return mission takes approximately three years to complete. Transit from Earth to Mars requires almost a single year. After a lapse of time of almost a year at Mars, during which orbital and surface operations can take place, and the correct return launch energy constraints are met, a Mars-to-Earth return flight can be initiated. This return leg also takes approximately one year. Opportunities to launch these 3-year sample return missions occur about every 2 years. The figure depicts schedules for flights to and from Mars for Earth launches in 2003, 2005, 2007 and 2009. Transits for less than 180 deg flight angle, measured from the sun, and more than 180 deg are both shown.

Jordan, James F.↗

Exploration Studies Technical Report - Volume 2: Studies Approach and Results

The NASA Office of Exploration has been tasked with defining and recommending alternatives for an early 1990's national decision on a focused program of human exploration of the solar system. The Mission Analysis and System Engineering (MASE) group, which is managed by the Exploration Studies Office at the Johnson Space Center, is responsible for coordinating the technical studies necessary for accomplishing such a task. This technical report describes the process that has been developed in a case study approach. The four case studies that were developed in FY88 include: 1. Human expedition to Phobos 2. Human expeditions to Mars 3. Lunar observatory 4. Lunar outpost to early Mars evolution The final outcome of this effort is a set of programmatic and technical conclusions and recommendations for the following year's work. Volume 2 describes the case study process, the technical results of each of the case studies, and opportunities for additional study. Included in the discussion of each case study is a description of the mission key features and profile. Mission definition and manifesting are detailed, followed by a description of the mission architecture and infrastructure. Systems concepts for the required orbital nodes, transportation systems, and planetary surface systems are discussed. Prerequisite implementation plans resulting from the synthesized case studies are described and in-depth assessments are presented.

Interplanetary flight↗

Results from the NASA Capability Roadmap Team for In-Situ Resource Utilization (ISRU)

On January 14, 2004, the President of the United States unveiled a new vision for robotic and human exploration of space entitled, "A Renewed Spirit of Discovery". As stated by the President in the Vision for Space Exploration (VSE), NASA must "... implement a sustained and affordable human and robotic program to explore the solar system and beyond " and ".. .develop new technologies and harness the moon's abundant resources to allow manned exploration of more challenging environments." A key to fulfilling the goal of sustained and affordable human and robotic exploration will be the ability to use resources that are available at the site of exploration to "live off the land" instead of bringing everything from Earth, known as In-Situ Resource Utilization (ISRU). ISRU can significantly reduce the mass, cost, and risk of exploration through capabilities such as: mission consumable production (propellants, fuel cell reagents, life support consumables, and feedstock for manufacturing & construction); surface construction (radiation shields, landing pads, walls, habitats, etc.); manufacturing and repair with in-situ resources (spare parts, wires, trusses, integrated systems etc.); and space utilities and power from space resources. On January 27th, 2004 the President's Commission on Implementation of U.S. Space Exploration Policy (Aldridge Committee) was created and its final report was released in June 2004. One of the report's recommendations was to establish special project teams to evaluate enabling technologies, of which "Planetary in situ resource utilization" was one of them. Based on the VSE and the commission's final report, NASA established fifteen Capability Roadmap teams, of which ISRU was one of the teams established. From Oct. 2004 to May 2005 the ISRU Capability Roadmap team examined the capabilities, benefits, architecture and mission implementation strategy, critical decisions, current state-of-the-art (SOA), challenges, technology gaps, and risks of ISRU for future human Moon and Mars exploration. This presentation will provide an overview of the ISRU capability, architecture, and implementation strategy examined by the ISRU Capability Roadmap team, along with a top-level review of ISRU benefits, resources and products of interest, and the current SOA in ISRU processes and systems. The presentation will also highlight the challenges of incorporating ISRU into future missions and the gaps in technologies and capabilities that need to be filled to enable ISRU.

Sanders, Gerald B.↗

Defining a Global Lunar Position, Navigation, and Timing System

As NASA seeks to fulfill its mission of extending humanity’s reach through exploration as delineated in the Moon to Mars Strategy and Objectives Development and the Moon to Mars Architecture Definition Document, accurate and timely position, navigation, and timing (PNT) services are critical in the architecture, identifying a need to expand a PNT capability to the full lunar proximity service volume. This is echoed in the White House Office of Science, Technology, and Policy Cislunar Science and Technology Strategy, which pinpoints the fundamental need for PNT infrastructure to enable and sustain a vibrant cislunar ecosystem. While the Human Lunar Return segment seeks commercial services to provide a PNT service over a South Pole service volume for a limited period per Earth day, meeting the Sustained Lunar Evolution segment requires a Lunar Navigation System (LNS) focused on delivery of precise and resilient PNT services across the lunar globe and near-Moon space. This presentation describes the pre-Phase A system concept for an orbital constellation, the requisite lunar surface-based in-situ monitor and control segment, and an Earth control segment to provide lunar PNT services out to 200km altitude above the surface. The LNS leverages the foundational efforts on lunar reference system components such as the Lunar Geodetic System, Lunar Time System, and lunar ephemeris and orientation critical to safe, accurate, and seamless navigation.

navigation↗

Long -Term Architecture Development For The Moon And M

Developing an enterprise-level architecture encompassing future human-robotic science and exploration at the Moon and Mars requires a visionary approach that ensures NASA is responsive to national priorities and global science and technology advancement objectives. While the initial capabilities needed to return humans to the Moon may be well understood, NASA is still formulating a long-term infrastructure at the Moon and working to narrow the trade space for the first human missions to Mars. This paper will focus on the formulation and current status of engineering and design applications for a long-term and robust lunar architecture that will implement the Artemis Base Camp concept, including pre-formulation activities and elements currently in formulation. Authors will demonstrate how the Moon-to-Mars campaign approach fosters commonality of requirements and standards across individual mission elements, as well as multi-destination systems and operations, to reduce risk and encourage healthy competition in the growing space market. Among the Artemis Base Camp elements discussed will be multiple surface mobility elements, a fixed, anchoring surface habitat, fission surface power, and an in-situ resource development pilot plant. The narrative will clearly illustrate the direct evolution of the base camp elements to a minimal Mars architecture concept, and also outline unique development efforts that will be required in the next decade to make it possible to send humans to the Red Planet as early as the 2030s.

Greg Chavers↗

Common Habitat Base Camp for Moon and Mars Surface Operations

The Common Habitat uses the SLS Core Stage Liquid Oxygen tank as the primary structure (similar to Skylab) and has an internal architecture compatible with microgravity, lunar gravity, and Mars gravity, such that identical versions of the same design can be used in all three environments. Applying the large dimensions and eight-person crew size of the Common Habitat to a surface architecture leads to a unique base camp configuration. A notional such base camp is described in this analysis. The base camp includes four distributed zones – habitation, landing, power, and resource production. The base camp is deployed and assembled in three phases: site preparation, element staging, and habitat delivery, each of which are briefly discussed. Crew arrival and departure is discussed, including variations caused by orbital mechanics-induced differences between the Moon and Mars base camps. Trash and logistics operations are described. Finally, crew operations within the base camp are described.

Lunar Outpost↗

International Coordination and Cooperation on LunaNet Spectrum

LunaNet is planned to be the network of networks operated by a set of cooperating organizations to provide interoperable Communications, networking, Position, Navigation, and Timing (CPNT) services to users on and around the Moon based on a framework of mutually agreed-upon standards, protocols, frequency bands and interface requirements. LunaNet follows a service-oriented architecture that is agnostic about the types of organizations that provide services, e.g., government, industry, or academia. LunaNet is open, scalable, resilient, secure, and extensible. To achieve these goals, LunaNet Service Providers (LNSP) must coordinate with each other to define and develop the architecture, to plan initial and evolved capabilities, and to operate their networks. One of the central LunaNet tenets is the use of shared spectrum. For example, the Lunar Augmented Navigation Service (LANS) acts like a Global Navigation Satellite System (GNSS) such as the US Global Positioning System (GPS) or European Galileo but the LNSPs’ contributions to LunaNet must use the same frequency band (2483.5 MHz-2500.0 MHz) and transmit the same waveform synchronized by highly accurate clocks so that Users ‘see’ one virtual network and use the same multilateration algorithm to determine their positions. This necessitates a high degree of spectrum coordination. NASA’s Lunar and Human Spaceflight Spectrum Management Team has been actively supporting development of the LunaNet Interoperability Specification (LNIS), soliciting inputs from spectrum policy and planning experts across NASA, ESA and JAXA. Cislunar spectrum use considerations have been studied and adjudicated within the Space Frequency Coordination Group (SFCG) and inform the ongoing discussion of a lunar communication and navigation architecture within the existing radio regulatory framework of the International Telecommunication Union, leading to the 2027 World Radiocommunication Conference (WRC-27). The frequency plan contained in the publicly released draft of the LunaNet Interoperability Specification reflects the initial phase of exploration (roughly to 2030) defining an optimal set of radio frequencies in appropriately allocated services consistent with WRC-23 decisions for use by known or planned CPNT applications, while striving to maximize coexistence and compatibility amongst cislunar systems and other systems within the near-Earth regime (< 2 million km from Earth). Important considerations include: protection of extremely sensitive receive-only radio astronomy systems on the lunar far side, known as the Shielded Zone of the Moon (SZM); compatibility between Direct with Earth (DWE) communications links and links needed to support relay satellites in lunar orbit with their customer systems on orbit or on the lunar surface; compatibility between multiple lunar surface communications systems and capabilities over varied and challenging terrain and distances; as well as ensuring compatibility and interoperability between navigation systems which either leverage Earth-based or in-situ lunar systems. In addition, the lunar CPNT architecture is envisioned to be the basis – with adjustments – of the future Mars CPNT architecture as we expand into the solar system using Interplanetary Networking (IPN). The second phase of lunar spectrum definition will address planned international capabilities for the next decade that will require action at WRC-27 and beyond. This paper will discuss each of these considerations in more depth and how the current LunaNet frequency plan addresses them.

LunaNet↗

Modular Growth NTR Space Transportation System for Future NASA Human Lunar, NEA and Mars Exploration Missions

The nuclear thermal rocket (NTR) is a proven, high thrust propulsion technology that has twice the specific impulse (I(sub sp) approx.900 s) of today's best chemical rockets. During the Rover and NERVA (Nuclear Engine for Rocket Vehicle Applications) programs, twenty rocket reactors were designed, built and ground tested. These tests demonstrated: (1) a wide range of thrust; (2) high temperature carbide-based nuclear fuel; (3) sustained engine operation; (4) accumulated lifetime; and (5) restart capability - everything required for affordable human missions beyond LEO. In NASA's recent Mars Design Reference Architecture (DRA) 5.0 study, the NTR was selected as the preferred propulsion option because of its proven technology, higher performance, lower IMLEO, versatile vehicle design, and growth potential. Furthermore, the NTR requires no large technology scale-ups since the smallest engine tested during the Rover program - the 25 klb(sub f) "Pewee" engine is sufficient for human Mars missions when used in a clustered engine configuration. The "Copernicus" crewed Mars transfer vehicle developed for DRA 5.0 was an expendable design sized for fast-conjunction, long surface stay Mars missions. It therefore has significant propellant capacity allowing a reusable "1-year" round trip human mission to a large, high energy near Earth asteroid (NEA) like Apophis in 2028. Using a "split mission" approach, Copernicus and its two key elements - a common propulsion stage and integrated "saddle truss" and LH2 drop tank assembly - configured as an Earth Return Vehicle / propellant tanker, can also support a short round trip (approx.18 month) / short orbital stay (60 days) Mars reconnaissance mission in the early 2030's before a landing is attempted. The same short stay orbital mission can be performed with an "all-up" vehicle by adding an "in-line" LH2 tank to Copernicus to supply the extra propellant needed for this higher energy, opposition-class mission. To transition to a reusable Mars architecture, Copernicus' saddle truss / drop tank assembly is replaced by an in-line tank and "star truss" assembly with paired modular drop tanks to further increase the vehicle's propellant capacity. Shorter "1-way" transit time fast-conjunction Mars missions are another possibility using this vehicle configuration but, as with reusability, increased launch mass is required. "Scaled down" versions of Copernicus (sized to a SLS lift capability of approx.70 t - 100 t) can be developed initially allowing reusable lunar cargo delivery and crewed landing missions, easy NEA missions (e.g., 2000 SG344 also in 2028) or an expendable mission to Apophis. Mission scenario descriptions, key vehicle features and operational characteristics are provided along with a brief discussion of NASA's current activities and its "pre-decisional" plans for future NTR development.

Borowski, Stanley K.↗

In Situ Resource Utilization (ISRU) on the Moon: Moessbauer Spectroscopy as a Process Monitor for Oxygen Production

Essential consumables like oxygen must to be produced from materials on the lunar surface to enable a sustained, long-term presence of humans on the Moon. The Outpost Precursor for ISRU and Modular Architecture (OPTIMA) field test on Mauna Kea, Hawaii, facilitated by the Pacific International Space Center for Exploration Systems (PISCES) of the University of Hawaii at Hilo, was designed to test the implementation of three hardware concepts to extract oxygen from the lunar regolith: Precursor ISRU Lunar Oxygen Testbed (PILOT) developed by Lockheed Martin in Littleton, CO; Regolith & Environmental Science and Oxygen & Lunar Volatiles Extraction (RESOLVE) developed at the NASA Kennedy Space Center in Cape Canaveral, FL; and ROxygen developed at the NASA Johnson Space Center in Houston, TX. The three concepts differ in design, but all rely on the same general principle: hydrogen reduction of metal cations (primarily Fe2+) bonded to oxygen to metal (e.g., Fe0) with the production of water. The hydrogen source is residual hydrogen in the fuel tanks of lunar landers. Electrolysis of the water produces oxygen and hydrogen (which is recycled). We used the miniaturized M ssbauer spectrometer MIMOS II to quantify the yield of this process on the basis of the quantity of Fe0 produced. Iron M ssbauer spectroscopy identifies iron-bearing phases, determines iron oxidation states, and quantifies the distribution of iron between mineral phases and oxidation states. The oxygen yield can be calculated by quantitative measurements of the distribution of Fe among oxidation states in the regolith before and after hydrogen reduction. A M ssbauer spectrometer can also be used as a prospecting tool to select the optimum feedstock for the oxygen production plants (e.g., high total Fe content and easily reduced phases). As a demonstration, a MIMOS II backscatter spectrometer (SPESI, Germany) was mounted on the Cratos rover (NASA Glenn Research Center in Cleveland, OH), which is one of several rover concepts designed to excavate and transfer regolith to the stationary hydrogen reduction plants. Spaceflight versions of the MIMOS II are part of the instrument payloads of NASA s Mars Exploration Rovers and still operating five years after landing on the surface of the planet. MIMOS II was also selected for Phobos-Grunt, a Russian sample return mission to the martian moon Phobos scheduled to launch in 2009, and ESA s ExoMars rover, an exobiology mission scheduled to launch in 2013. An advanced version of the instrument is currently under development. A new detector system with a higher energy resolution will not only reduce the necessary measurement time considerably, but also allow the simultaneous acquisition of an X-ray fluorescence spectrum to determine the elemental composition of samples.

Morris, R.V.↗

NASA’s Space Launch System: Building A Capability for Science and Exploration

NASA’s Space Launch System, designed for human exploration of deep space and offering enabling benefits for a variety of science missions, is entering the final stages of preparation for its first launch, while simultaneously making progress toward future missions. SLS offers robust payload mass, volume, and characteristic energy that can be used not only for human exploration but for a variety of science missions, including probes to the outer solar system and beyond. In addition, while the vehicle is optimized to be a super-heavy lifter for lunar orbit as a staging area for the lunar surface or Mars, the addition of commercially available propulsion systems as third and/or fourth stages allows SLS to deliver unmatched performance for ultra-high C3 missions. Studies show that while the baseline SLS Block 2 vehicle can deliver about 8 t directly to the Jovian system at a C3 of 83, the addition of a Centaur upper stage would raise that mass to more than 15 t. The New Horizons spacecraft, with mass less than 0.5 t, launched toward Pluto with a record C3 of 158 km2/sec2. By comparison, an SLS Block 2 with an Orion 30B and Star 48BV payload stages could launch equivalent mass to a C3 more than double that of the New Horizons launch. (While the study has been conducted based on contemporary cryo stages and solid stages, this analysis provides real-world data for the range of performance this capability enables even as the specific stages available evolve.) Studies have shown it may be possible to reach 80-90 AU within a decade. The initial Block 1 vehicle for the first launch, Artemis I, is completely manufactured and all the elements are at NASA’s Kennedy Space Center (KSC) with the exception of the core stage, and manufacturing is in progress for the next several flights. Following the completion of the Green Run test series at NASA’s Stennis Space Center, the Artemis I core stage will be refurbished and delivered to KSC for stacking for launch in the second half of 2021. With the Artemis I vehicle fully manufactured and assembly of solid rocket boosters beginning, NASA and its industry partners have made significant progress manufacturing successive vehicles. Hardware for the next two launches is currently in production. NASA is committed to SLS as a key component of its launch architecture. Agency planning manifests outline the launch vehicle’s role in human lunar exploration over the next decade as it moves from its Block1 configuration to its intermediate Block 1B configuration and its ultimate Block 2 configuration.In addition, NASA has issued contracts with prime contractors for SLS hardware for delivery well into the 2030s.

Robert W. Stough↗

Simultaneous Two-Way Doppler and Ranging for Multiple Spacecraft at Mars: Flight Radio Tracking System Design and Performance Simulations

Mars exploration requires multiple orbiters and surface infrastructures on Mars. Location determination is essential to support various human and robotic activities on the Mars surface and in orbits. Robust communication coverage is required for data transmission between assets on Mars surface and orbiters in addition to the communication between orbiters and Earth. We proposed a notional Mars Regional Navigation Satellite System (MRNSS) that provides continuous or near-continuous in-situ navigation and timing services for the robotic and human missions in the vicinity of a Mars landing site. For such a system, the Earth’s deep space stations have to perform orbit determination (OD) for the Mars orbiters so that their locations are known to a reasonable degree of accuracy. This provides the surface and orbiting user vehicles the ability to estimate their locations using the orbiter-vehicle range measurements. Two important inputs for accurate OD are 2-way Doppler and ranging measurements derived from the transmitted and received radio signals. We also introduced a new flight-ground collaborative architecture that provides simultaneous Doppler and ranging measurements for multiple spacecraft in the Mars vicinity, using an example of the Mars landing site Utopia Planitia and four Mars orbiters, all communicating with Earth via twoway communications in the X-band frequency range. One key component of this architecture is that each spacecraft uses a smart frequency sweeping algorithm that acquires and tracks the uplink signals with high Doppler and Doppler rate residuals. In this paper, we simulate the Doppler and Doppler rate profiles of the Mars orbiters of the MRNSS and assessed the acquisition and tracking performances.

Divsalar, Dariush↗

Advanced Communication and Networking Technologies for Mars Exploration

Next-generation Mars communications networks will provide communications and navigation services to a wide variety of Mars science vehicles including: spacecraft that are arriving at Mars, spacecraft that are entering and descending in the Mars atmosphere, scientific orbiter spacecraft, spacecraft that return Mars samples to Earth, landers, rovers, aerobots, airplanes, and sensing pods. In the current architecture plans, the communication services will be provided using capabilities deployed on the science vehicles as well as dedicated communication satellites that will together make up the Mars network. This network will evolve as additional vehicles arrive, depart or end their useful missions. Cost savings and increased reliability will result from the ability to share communication services between missions. This paper discusses the basic architecture that is needed to support the Mars Communications Network part of NASA's Space Science Enterprise (SSE) communications architecture. The network may use various networking technologies such as those employed in the terrestrial Internet, as well as special purpose deep-space protocols to move data and commands autonomously between vehicles, at disparate Mars vicinity sites (on the surface or in near-Mars space) and between Mars vehicles and earthbound users. The architecture of the spacecraft on-board local communications is being reconsidered in light of these new networking requirements. The trend towards increasingly autonomous operation of the spacecraft is aimed at reducing the dependence on resource scheduling provided by Earth-based operators and increasing system fault tolerance. However, these benefits will result in increased communication and software development requirements. As a result, the envisioned Mars communications infrastructure requires both hardware and protocol technology advancements. This paper will describe a number of the critical technology needs and some of the ongoing research activities.

Bhasin, Kul↗

Space Launch System Payload Stage Capability for Ultra-High Characteristic Energy Missions

The Space Launch System (SLS) vehicle is NASA’s cornerstone capability for a new era of human and robotic exploration of deep space. The unrivalled performance of SLS provides the capability to launch the first woman and next man to walk on the lunar surface and to support development of a sustained human presence in cislunar space, and ultimately human missions to Mars. As an evolvable capability with unique launch performance, the opportunities enabled by SLS also include game-changing benefits for science missions, including probes to the outer solar system and beyond. For the last two years, the SLS Program has worked with the Interstellar Probe team at the Johns Hopkins University Applied Physics Laboratory(APL) to provide data that describe how SLS could support a mission that would break through the boundary of the heliosphere and into pristine interstellar space only a decade after launch, enabling earlier science return and greatly increasing spacecraft life in the interstellar medium. In record-breaking time, the ISP as launched on SLS may answer questions raised by the extended mission of NASA’s Voyager spacecraft. While SLS and its efficient Exploration Upper Stage (EUS) offer benefits for exploration of the outer planets, adding one or more additional stages to this architecture makes it even more capable for missions beyond our solar system, offering more realistically appealing flight times that would allow the mission scientists to reap the rewards of exploration. During the time the SLS Program has been working with the Interstellar Probe team, it has identified an expedited path to the Block 2 capability planned for the Interstellar Probe mission, and further matured performance numbers for diverse multi-stage configurations using a combination of commercially available liquid hydrogen (LH2)/liquid oxygen (LOX) upper stages and solid motor kick stages. That work has demonstrated the SLS payload stage capability provides significant benefits and opens trade space for multiple missions in consideration during planning for the next Planetary Science and Astrobiology Decadal Survey. This presentation details the significant benefits SLS can provides for very high characteristic (C3) energy missions by coupling the capabilities of SLS to current commercial rocket propulsion stage systems. These capabilities are explored specifically in the context of an Interstellar Probe architecture in which a small, capable science probe, coupled with carefully tailored mission design trajectories, could be used to explore the outer solar system and the interstellar medium. The presentation will also address the operational logistics of integrating such a mission, explaining the options available for “non-standard” SLS payloads, including processing those with radioisotope power generators or additional propulsion stages. An SLS system overview and capabilities will be presented, along with vehicle configuration and orbit performance capability studies, explaining how SLS is enabling for a variety of high-energy science mission profiles, including launching an exploratory probe bound for interstellar space only a decade after launch.

Rob Stough↗