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NASA NTRS2018

Initial Results of the Software-Driven Navigation for Station Experiment

To enable the next generation of robotic and human exploration of the solar system, improvements are needed to enable robust and accurate autonomous navigation. The purpose of this work is to take advantage of the growth in and use of software-defined platforms to incorporate additional navigation capability on existing assets, while also incorporating with new vehicle designs. The Software-driven Navigation for Station Experiment focuses on implementing two soft solutions to this: transmitting pseudolite signals to perform ranging and Doppler measurements as part of the signal coding (similar to underlying Global Navigation Satellite System approaches), and the Multi-spacecraft Autonomous Positioning System, which uses existing communication protocols to embed navigation and timing information to be shared among all assets in a peer-to-peer network. These technologies were implemented on the SCaN Testbed onboard the International Space Station and exercised over the course of mid-June and late-July 2018. This paper will discuss the operational architecture, experiment plan, and initial results from the data collected. One of the key conclusions of this work is the strong need for stable accurate clock synchronization across the dispersed space network.

Anzalone, Evan J.↗
NASA NTRS2008

NASA Propulsion Investments for Exploration and Science

The National Aeronautics and Space Administration (NASA) invests in chemical and electric propulsion systems to achieve future mission objectives for both human exploration and robotic science. Propulsion system requirements for human missions are derived from the exploration architecture being implemented in the Constellation Program. The Constellation Program first develops a system consisting of the Ares I launch vehicle and Orion spacecraft to access the Space Station, then builds on this initial system with the heavy-lift Ares V launch vehicle, Earth departure stage, and lunar module to enable missions to the lunar surface. A variety of chemical engines for all mission phases including primary propulsion, reaction control, abort, lunar ascent, and lunar descent are under development or are in early risk reduction to meet the specific requirements of the Ares I and V launch vehicles, Orion crew and service modules, and Altair lunar module. Exploration propulsion systems draw from Apollo, space shuttle, and commercial heritage and are applied across the Constellation architecture vehicles. Selection of these launch systems and engines is driven by numerous factors including development cost, existing infrastructure, operations cost, and reliability. Incorporation of green systems for sustained operations and extensibility into future systems is an additional consideration for system design. Science missions will directly benefit from the development of Constellation launch systems, and are making advancements in electric and chemical propulsion systems for challenging deep space, rendezvous, and sample return missions. Both Hall effect and ion electric propulsion systems are in development or qualification to address the range of NASA s Heliophysics, Planetary Science, and Astrophysics mission requirements. These address the spectrum of potential requirements from cost-capped missions to enabling challenging high delta-v, long-life missions. Additionally, a high specific impulse chemical engine is in development that will add additional capability to performance-demanding space science missions. In summary, the paper provides a survey of current NASA development and risk reduction propulsion investments for exploration and science.

Smith, Bryan K.↗
NASA NTRS2010

Verification Challenges of Dynamic Testing of Space Flight Hardware

The Six Degree-of-Freedom Dynamic Test System (SDTS) is a test facility at the National Aeronautics and Space Administration (NASA) Johnson Space Center in Houston, Texas for performing dynamic verification of space structures and hardware. Some examples of past and current tests include the verification of on-orbit robotic inspection systems, space vehicle assembly procedures and docking/berthing systems. The facility is able to integrate a dynamic simulation of on-orbit spacecraft mating or demating using flight-like mechanical interface hardware. A force moment sensor is utilized for input to the simulation during the contact phase, thus simulating the contact dynamics. While the verification of flight hardware presents many unique challenges, one particular area of interest is with respect to the use of external measurement systems to ensure accurate feedback of dynamic contact. There are many commercial off-the-shelf (COTS) measurement systems available on the market, and the test facility measurement systems have evolved over time to include two separate COTS systems. The first system incorporates infra-red sensing cameras, while the second system employs a laser interferometer to determine position and orientation data. The specific technical challenges with the measurement systems in a large dynamic environment include changing thermal and humidity levels, operational area and measurement volume, dynamic tracking, and data synchronization. The facility is located in an expansive high-bay area that is occasionally exposed to outside temperature when large retractable doors at each end of the building are opened. The laser interferometer system, in particular, is vulnerable to the environmental changes in the building. The operational area of the test facility itself is sizeable, ranging from seven meters wide and five meters deep to as much as seven meters high. Both facility measurement systems have desirable measurement volumes and the accuracies vary within the respective volumes. In addition, because this is a dynamic facility with a moving test bed, direct line-of-sight may not be available at all times between the measurement sensors and the tracking targets. Finally, the feedback data from the active test bed along with the two external measurement systems must be synchronized to allow for data correlation. To ensure the desired accuracy and resolution of these systems, calibration of the systems must be performed regularly. New innovations in sensor technology itself are periodically incorporated into the facility s overall measurement scheme. In addressing the challenges of the measurement systems, the facility is able to provide essential position and orientation data to verify the dynamic performance of space flight hardware.

Winnitoy, Susan↗
NASA NTRS2012

Optical Frequency Optimization of a High Intensity Laser Power Beaming System Utilizing VMJ Photovoltaic Cells

An effective form of wireless power transmission (WPT) has been developed to enable extended mission durations, increased coverage and added capabilities for both space and terrestrial applications that may benefit from optically delivered electrical energy. The high intensity laser power beaming (HILPB) system enables long range optical 'refueling" of electric platforms such as micro unmanned aerial vehicles (MUAV), airships, robotic exploration missions and spacecraft platforms. To further advance the HILPB technology, the focus of this investigation is to determine the optimal laser wavelength to be used with the HILPB receiver, which utilizes vertical multi-junction (VMJ) photovoltaic cells. Frequency optimization of the laser system is necessary in order to maximize the conversion efficiency at continuous high intensities, and thus increase the delivered power density of the HILPB system. Initial spectral characterizations of the device performed at the NASA Glenn Research Center (GRC) indicate the approximate range of peak optical-to-electrical conversion efficiencies, but these data sets represent transient conditions under lower levels of illumination. Extending these results to high levels of steady state illumination, with attention given to the compatibility of available commercial off-the-shelf semiconductor laser sources and atmospheric transmission constraints is the primary focus of this paper. Experimental hardware results utilizing high power continuous wave (CW) semiconductor lasers at four different operational frequencies near the indicated band gap of the photovoltaic VMJ cells are presented and discussed. In addition, the highest receiver power density achieved to date is demonstrated using a single photovoltaic VMJ cell, which provided an exceptionally high electrical output of 13.6 W/sq cm at an optical-to-electrical conversion efficiency of 24 percent. These results are very promising and scalable, as a potential 1.0 sq m HILPB receiver of similar construction would be able to generate 136 kW of electrical power under similar conditions.

Raible, Daniel E.↗
NASA NTRS1989

Telescience at the University of California, Berkeley

The University of California at Berkeley (UCB) is a member of a university consortium involved in telescience testbed activities under the sponsorship of NASA. Our Telescience Testbed Project consists of three experiments using flight hardware being developed for the Extreme Ultraviolet Explorer project at UCB's Space Sciences Laboratory. The first one is a teleoperation experiment investigating remote instrument control using a computer network such as the Internet. The second experiment is an effort to develop a system for operation of a network of remote workstations allowing coordinated software development, evaluation, and use by widely dispersed groups. The final experiment concerns simulation as a method to facilitate the concurrent development of instrument hardware and support software. We describe our progress in these areas.

Telemetry/instrumentation/methods↗
NASA NTRS2024

Cost and Benefit Analysis of Mitigating, Tracking, and Remediating Orbital Debris

Orbital debris may collide with crewed and robotic spacecraft, placing them at risk. The wide range of debris, from 9,000-kilogram rocket bodies to millions of millimeter-size debris, has led to a similarly wide range of proposed actions for addressing the risks posed by debris. However, the costs and benefits of these actions have historically been unknown. This is a challenge for decision makers who are choosing which actions to support through technology development or policy changes. NASA’s Office of Technology, Policy, and Strategy is addressing these technical and economic uncertainties by building a capability to (1) complete rigorous calculations of the net present value of each action, (2) identify an optimal portfolio of actions to reduce risk, and (3) quantitatively analyze policies related to space sustainability. This report describes our progress toward that capability and to solicit feedback from the space and economic communities. Our previous work, referred to here as Phase 1, assessed the costs and benefits of performing debris remediation on operationally relevant timescales. The current analysis contains major updates to the risk model used in Phase 1 and expands the breadth of actions considered to include mitigating the creation of debris, improving the ability to track debris, and more methods for cleaning up existing debris. We demonstrate that our approach of measuring risks in dollars allows for the effectiveness of seemingly incommensurate actions to be compared and generates insights that other approaches to measuring risk have missed.

Jericho Locke↗
NASA NTRS2024

Cost and Benefit Analysis of Mitigating, Tracking, and Remediating Orbital Debris

Presentation accompanying the technical report with the same name. The abstract for the report and the full study is repeated below. Orbital debris may collide with crewed and robotic spacecraft, placing them at risk. The wide range of debris, from 9,000-kilogram rocket bodies to millions of millimeter-size debris, has led to a similarly wide range of proposed actions for addressing the risks posed by debris. However, the costs and benefits of these actions have historically been unknown. This is a challenge for decision makers who are choosing which actions to support through technology development or policy changes. NASA’s Office of Technology, Policy, and Strategy is addressing these technical and economic uncertainties by building a capability to (1) complete rigorous calculations of the net present value of each action, (2) identify an optimal portfolio of actions to reduce risk, and (3) quantitatively analyze policies related to space sustainability. This report describes our progress toward that capability and to solicit feedback from the space and economic communities. Our previous work, referred to here as Phase 1, assessed the costs and benefits of performing debris remediation on operationally relevant timescales. The current analysis contains major updates to the risk model used in Phase 1 and expands the breadth of actions considered to include mitigating the creation of debris, improving the ability to track debris, and more methods for cleaning up existing debris. We demonstrate that our approach of measuring risks in dollars allows for the effectiveness of seemingly incommensurate actions to be compared and generates insights that other approaches to measuring risk have missed.

Jericho Locke↗
NASA NTRS2014

Controlled Ascent From the Surface of an Asteroid

The National Aeronautics and Space Administration (NASA) is currently investigating a conceptual robotic mission to collect a small boulder up to 4 m in diameter resting on the surface of a large Near Earth Asteroid (NEA). Because most NEAs are not well characterized, a great range of uncertainties in boulder mass properties and NEA surface characteristics must be considered in the design of this mission. These uncertainties are especially significant when the spacecraft ascends with the boulder in tow. The most important requirement during ascent is to keep the spacecraft in an upright posture to maintain healthy ground clearances for the two large solar arrays. This paper focuses on the initial stage (the first 50 m) of ascent from the surface. Specifically, it presents a sensitivity study of the solar array ground clearance, control authority, and accelerations at the array tips in the presence of a variety of uncertainties including various boulder sizes, densities, shapes and orientations, locations of the true center of mass, and push-off force distributions. Results are presented, and appropriate operations are recommended in the event some of the off-nominal cases occur.

Shen, Haijun↗
NASA NTRSDate not supplied

The Gateway Program as Part of NASA’s Plans for Human Exploration Beyond Low Earth Orbit

This paper provides an overview and status of Gateway, humanity’s first space station in lunar orbit as a vital component of the NASA-led Artemis missions to return humans to the Moon as preparation for the first human missions to Mars. Gateway is an aggregation point in deep space for a variety of spacecraft, including the crewed Orion vehicle, the Human Landing System that will ferry astronauts to and from the lunar surface, logistics supply craft, and vehicles transiting further into deep space beyond the Earth-Moon system, such as to Mars. NASA is building on decades of partnership with space agencies on three continents and multiple commercial partners to design, build, and launch Gateway’s core elements to near-rectilinear halo orbit (NRHO) around the Moon, where it will operate for a minimum of 15 years. Gateway is humanity’s next in-space science utilization platform, and its first in deep space, with three science payloads already selected to study solar and cosmic radiation. This paper will provide an overview of the Gateway space station’s major components in various stages of development, including the Power and Propulsion Element (PPE), Habitation and Logistics Outpost (HALO), the International Habitation (I-Hab) module, ESPRIT Refueling Module (ERM), the planned airlock, advanced external robotics systems, Deep Space Logistics supply craft, and next-generation autonomous Vehicle System Manager software. It will also provide an overview of how Gateway will be utilized for science, and highlight the space station’s multilateral governance structure and international agreements.

Emma Lehnhardt↗
NASA NTRS1999

Architectural Design for a Mars Communications and Navigation Orbital Infrastructure

The planet Mars has become the focus of an intensive series of missions that span decades of time, a wide array of international agencies and an evolution from robotics to humans. The number of missions to Mars at any one time, and over a period of time, is unprecedented in the annals of space exploration. To meet the operational needs of this exploratory fleet will require the implementation of new architectural concepts for communications and navigation. To this end, NASA's Jet Propulsion Laboratory has begun to define and develop a Mars communications and navigation orbital infrastructure. This architecture will make extensive use of assets at Mars, as well as use of traditional Earth-based assets, such as the Deep Space Network, DSN. Indeed, the total system can be thought of as an extension of DSN nodes and services to the Mars in-situ region. The concept has been likened to the beginnings of an interplanetary Internet that will bring the exploration of Mars right into our living rooms. The paper will begin with a high-level overview of the concept for the Mars communications and navigation infrastructure. Next, the mission requirements will be presented. These will include the relatively near-term needs of robotic landers, rovers, ascent vehicles, balloons, airplanes, and possibly orbiting, arriving and departing spacecraft. Requirements envisioned for the human exploration of Mars will also be described. The important Mars orbit design trades on telecommunications and navigation capabilities will be summarized, and the baseline infrastructure will be described. A roadmap of NASA's plan to evolve this infrastructure over time will be shown. Finally, launch considerations and delivery to Mars will be briefly treated.

Ceasrone R. J.↗
NASA NTRS2010

Radiation Beamline Testbeds for the Simulation of Planetary and Spacecraft Environments for Human and Robotic Mission Risk Assessment

The Center for Radiation Engineering and Science for Space Exploration (CRESSE) at Prairie View A&M University, Prairie View, Texas, USA, is establishing an integrated, multi-disciplinary research program on the scientific and engineering challenges faced by NASA and the international space community caused by space radiation. CRESSE focuses on space radiation research directly applicable to astronaut health and safety during future long term, deep space missions, including Martian, lunar, and other planetary body missions beyond low earth orbit. The research approach will consist of experimental and theoretical radiation modeling studies utilizing particle accelerator facilities including: 1. NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory; 2. Proton Synchrotron at Loma Linda University Medical Center; and 3. Los Alamos Neutron Science Center (LANSCE) at Los Alamos National Laboratory. Specifically, CRESSE investigators are designing, developing, and building experimental test beds that simulate the lunar and Martian radiation environments for experiments focused on risk assessment for astronauts and instrumentation. The testbeds have been designated the Bioastronautics Experimental Research Testbeds for Environmental Radiation Nostrum Investigations and Education (BERT and ERNIE). The designs of BERT and ERNIE will allow for a high degree of flexibility and adaptability to modify experimental configurations to simulate planetary surface environments, planetary habitats, and spacecraft interiors. In the nominal configuration, BERT and ERIE will consist of a set of experimental zones that will simulate the planetary atmosphere (Solid CO2 in the case of the Martian surface.), the planetary surface, and sub-surface regions. These experimental zones can be used for dosimetry, shielding, biological, and electronic effects radiation studies in support of space exploration missions. BERT and ERNIE are designed to be compatible with the experimental areas associated with the above facilities. CRESSE has broad expertise in space radiation in the areas of space radiation environment modeling, Monte-Carlo radiation transport modeling, space radiation instrumentation and dosimetry, radiation effects on electronics, and multi-functional composite shielding materials. The BERT and ERNIE testbeds will be utilized in individual and collaborative research incorporating this expertise. The research goal is to maximize the technical readiness level (TRL) of radiation instrumentation for human and robotic missions, optimizing the return value of CRESSE for NASA exploration and international co-operative missions. Outcomes and knowledge from research utilizing BERT and ERNIE will be applied to a variety of scientific and engineering disciplines vital for safe and reliable execution of future space exploration missions, which can be negatively impacted by the space radiation environment. The testbeds will be central to a variety of university educational activities and educational goals of NASA. Specifically, BERT and ERNIE will enhance educational opportunities in science, technology, engineering and mathematics (STEM) disciplines for engineering and science students at PVAMU, a historically black college/university. Preliminary data on prototype testbed configurations, including simulated lunar regolith (JSC-1A stimulant based on Apollo 11 samples), regolith/polyethylene composites, and dry ice, will be presented to demonstrate the usefulness of BERT and ERNIE in radiation beam line experiments.

Wilkins, Richard↗
NASA NTRS2011

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 NASA's 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.

Hoffman, S. J.↗
NASA NTRS2017

NIAC Phase II Orbiting Rainbows: Future Space Imaging with Granular Systems

Inspired by the light scattering and focusing properties of distributed optical assemblies in Nature, such as rainbows and aerosols, and by recent laboratory successes in optical trapping and manipulation, we propose a unique combination of space optics and autonomous robotic system technology, to enable a new vision of space system architecture with applications to ultra-lightweight space optics and, ultimately, in-situ space system fabrication. Typically, the cost of an optical system is driven by the size and mass of the primary aperture. The ideal system is a cloud of spatially disordered dust-like objects that can be optically manipulated: it is highly reconfigurable, fault-tolerant, and allows very large aperture sizes at low cost. This new concept is based on recent understandings in the physics of optical manipulation of small particles in the laboratory and the engineering of distributed ensembles of spacecraft swarms to shape an orbiting cloud of micron-sized objects. In the same way that optical tweezers have revolutionized micro- and nano-manipulation of objects, our breakthrough concept will enable new large scale NASA mission applications and develop new technology in the areas of Astrophysical Imaging Systems and Remote Sensing because the cloud can operate as an adaptive optical imaging sensor. While achieving the feasibility of constructing one single aperture out of the cloud is the main topic of this work, it is clear that multiple orbiting aerosol lenses could also combine their power to synthesize a much larger aperture in space to enable challenging goals such as exo-planet detection. Furthermore, this effort could establish feasibility of key issues related to material properties, remote manipulation, and autonomy characteristics of cloud in orbit. There are several types of endeavors (science missions) that could be enabled by this type of approach, i.e. it can enable new astrophysical imaging systems, exo-planet search, large apertures allow for unprecedented high resolution to discern continents and important features of other planets, hyperspectral imaging, adaptive systems, spectroscopy imaging through limb, and stable optical systems from Lagrange-points. Furthermore, future micro-miniaturization might hold promise of a further extension of our dust aperture concept to other more exciting smart dust concepts with other associated capabilities. Our objective in Phase II was to experimentally and numerically investigate how to optically manipulate and maintain the shape of an orbiting cloud of dust-like matter so that it can function as an adaptable ultra-lightweight surface. Our solution is based on the aperture being an engineered granular medium, instead of a conventional monolithic aperture. This allows building of apertures at a reduced cost, enables extremely fault-tolerant apertures that cannot otherwise be made, and directly enables classes of missions for exoplanet detection based on Fourier spectroscopy with tight angular resolution and innovative radar systems for remote sensing. In this task, we have examined the advanced feasibility of a crosscutting concept that contributes new technological approaches for space imaging systems, autonomous systems, and space applications of optical manipulation. The proposed investigation has matured the concept that we started in Phase I to TRL 3, identifying technology gaps and candidate system architectures for the space-borne cloud as an aperture.

Quadrelli, Marco B.↗
NASA NTRS1994

Design of the MESUR/pathfinder microrover

The use of unmanned robotic vehicles to assist in the exploration of Mars and other planets has been of interest to the National Aeronautics and Space Administration (NASA) for several decades and has been the focus of an ongoing research program at the Jet Propulsion Laboratory (JPL) for a similar period of time. As a result of these research activities, JPL is in the process of designing and building a small (7-9 kg) microrover to be flown aboard the Mars Environmental Survey Mission (MESUR)/Pathfinder spacecraft, which is tentatively to be launched to Mars in late 1997. The microrover will perform a variety of technology experiments designed to provide information critical to the design of future planetary rovers. In addition, the microrover will perform several science and lander related experiments using specialized onboard instruments. To enable the microrover to perform these experiments at selected target areas and at the same time deal with the long time delays (and limited communications bandwidth), a control/navigation approach combining the use of operator-designated waypoints and onboard behavior control has been adopted. The design of the MESUR/Pathfinder microrover and the overall manner in which it is controlled are described herein.

Stone, Henry W.↗
NASA NTRSDate not supplied

A Cost and Benefit Analysis of Orbital Debris Remediation, Mitigation,Tracking, and Characterization

Orbital debris may collide with crewed and robotic spacecraft, placing them at risk. The wide range of debris, from 9,000-kilogram rocket bodies to millions of millimeter-size debris, has led to a similarly wide range of proposed actions for addressing the risks posed by debris. However, the costs and benefits of these actions have historically been unknown. This is a challenge for decision makers who are choosing which actions to support through technology development or policy changes. NASA’s Office of Technology, Policy, and Strategy is addressing these technical and economic uncertainties by building a capability to (1) complete rigorous calculations of the net present value of each action, (2) identify an optimal portfolio of actions to reduce risk, and (3) quantitatively analyze policies related to space sustainability. This report describes our progress toward that capability and to solicit feedback from the space and economic communities. Our previous work(Colvin, Karcz, and Wusk. 2023), referred to here as Phase 1, assessed the costs and benefits of performing debris remediation on operationally relevant timescales. The current paper summarizes the work of Locke and Colvin (2024), which contains major updates to the risk model used in Phase 1 and expands the breadth of actions considered to include mitigating the creation of debris, improving the ability to track debris, and more methods for cleaning up existing debris. We demonstrate that our approach of measuring risks in dollars allows for the effectiveness of seemingly incommensurate actions to be compared and generates insights that other approaches to measuring risk have missed.

Orbital Debris↗
NASA NTRS1990

Third Annual Workshop on Space Operations Automation and Robotics (SOAR 1989)

Papers presented at the Third Annual Workshop on Space Operations Automation and Robotics (SOAR '89), hosted by the NASA Lyndon 8. Johnson Space Center at Houston, Texas, on July 25-27, 1989, are documented herein. During the three days, approximately 100 technical papers wer3 presented by experts from NASA, the USAF, universities, and technical companies. Also held were panel discussions on Air Force/NASA AI Overview and Expert System Verification and Validation. Tutorial sessions included Neural Networks; Theory and Application of Back Propagation; Verification and Validation of Expert Systems/ Evaluation of Expert System Tools; and Technical Environment for Modular Architectures for Robotics in Space; and are not documented herein. Technical topics addressed included intelligent systems, robotics, human factors, and environment.

Knowledge representation↗
NASA NTRS2010

Human Exploration Using Real-Time Robotic Operations (HERRO)- Crew Telerobotic Control Vehicle (CTCV) Design

The HERRO concept allows real time investigation of planets and small bodies by sending astronauts to orbit these targets and telerobotically explore them using robotic systems. Several targets have been put forward by past studies including Mars, Venus, and near Earth asteroids. A conceptual design study was funded by the NASA Innovation Fund to explore what the HERRO concept and it's vehicles would look like and what technological challenges need to be met. This design study chose Mars as the target destination. In this way the HERRO studies can define the endpoint design concepts for an all-up telerobotic exploration of the number one target of interest Mars. This endpoint design will serve to help planners define combined precursor telerobotics science missions and technology development flights. A suggested set of these technologies and demonstrator missions is shown in Appendix B. The HERRO concept includes a crewed telerobotics orbit vehicle as well three Truck rovers, each supporting two teleoperated geologist robots Rockhounds (each truck/Rockhounds set is landed using a commercially launched aeroshell landing system.) Options include a sample ascent system teamed with an orbital telerobotic sample rendezvous and return spacecraft (S/C) (yet to be designed). Each truck rover would be landed in a science location with the ability to traverse a 100 km diameter area, carrying the Rockhounds to 100 m diameter science areas for several week science activities. The truck is not only responsible for transporting the Rockhounds to science areas, but also for relaying telecontrol and high-res communications to/from the Rockhound and powering/heating the Rockhound during the non-science times (including night-time). The Rockhounds take the place of human geologists by providing an agile robotic platform with real-time telerobotics control to the Rockhound from the crew telerobotics orbiter. The designs of the Truck rovers and Rockhounds will be described in other publications. This document focuses on the CTCV design.

Oleson, Steven R.↗
NASA NTRSDate not supplied

NASA's Space Launch System Begins Integration, Stacking in Preparation for Artemis I Launch

The Artemis era of human lunar exploration is nearing take-off as NASA’s new super heavy-lift launch vehicle, the Space Launch System (SLS), begins stack-ing and integration operations in mid-2020 at Kennedy Space Center (KSC) in Florida. With a planned upgrade path to progressively more powerful vehicles and availability in crew and cargo configurations, SLS provides a unique and flexible launch solution to send crew, large-scale infrastructure and robotic probes to deep space. The SLS Block 1 vehicle, the initial variant to fly, is optimized for lunar missions with a proven propulsion system consisting of four liquid hydrogen (LH2)/liquid oxygen (LOX)-fed RS-25 engines and twin five-segment solid rocket boosters (SRBs). The Block 1 vehicle can also be outfitted with an industry-standard 5 m-class payload fairing (the “cargo” configuration) and will launch at least 27 metric tons (t) of mass to trans-lunar injection (TLI). SLS is the backbone of NASA’s Artemis program, which will return the agency’s human spaceflight program to the Moon for the first time since 1972. For the Artemis I mission, SLS will send an uncrewed Orion spacecraft to TLI, where it will enter a distant retrograde lunar orbit and fly 38,000 nmi past the Moon – farther than any spacecraft built for humans has ever traveled. The SLS Block 1 vehicle for Artemis I completed manufacturing in 2019. Several elements, including the upper stage, have been delivered to the Exploration Ground Systems (EGS) program at KSC and are being prepped for integration and stack-ing. The five-segment solid rocket boosters – the largest and most powerful ever built for flight – are also complete. The booster motor segments for the Artemis I flight are scheduled to ship from prime contractor Northrop Grumman’s Utah facilities and begin stacking and integration at KSC in June 2020. The SLS core stage is the largest rocket stage NASA has ever built in terms of volume and height, and includes the avionics and the tanks that feed cryogenic propellant to the four RS-25s (formerly Space Shuttle Main Engines [SSMEs]). They have been modified with an updated controller and nozzle insulation to protect them from the hotter launch environment. The SLS core stage is currently being test-ed at NASA’s Stennis Space Center (SSC) in a series of “green run” tests to verify it meets design and performance requirements. Following the green run test series, which is scheduled to culminate with a full-duration hot-fire of the four RS-25 engines, the core stage will ship to KSC and be stacked between the sol-id rocket boosters in the Vehicle Assembly Building (VAB). Integration of the vehicle will continue with the upper stage, known as the Interim Cryogenic Propulsion Stage (ICPS) and the Launch Vehicle Stage Adapter (LVSA) on the core stage. Another adapter, the Orion Stage Adapter (OSA), connects SLS to Orion and provides housing for 13 6U CubeSat payloads manifested on Artemis I. The CubeSats will be released in deep space after Orion separates from the vehicle, and the flight marks the first ride share opportunity for independent small-sats to deep space. The second major SLS variant to come online, Block 1B, replaces the single-engine ICPS with a four-engine LH2/LOX Exploration Upper Stage (EUS). This more powerful upper stage, along with other vehicle up-grades, will enable the Block 1B vehicle to launch 38-42 t to TLI, depending on crew or cargo configuration. The final evolution of the vehicle, Block 2, will onramp evolved solid rocket boosters to increase mass to TLI to 43-46 t, de-pending on crew or cargo configuration. The Block 1B/Block 2 vehicles can be outfitted with an 8.4 m-diameter payload fairing in 19.1 m or 27.4 m lengths, to provide unprecedented volume for payloads. With the initial Block 1 vehicle completely manufactured and the core stage in final testing before shipping to KSC, the SLS Program and its industry partners have made significant progress manufacturing subsequent vehicles. For the second Block 1 vehicle, the solid rocket motor segments are complete, as are the RS-25 engines with controllers. All five major components of the Artemis II core stage – the forward skirt, LOX and LH2 tanks, intertank and engine section – are manufactured and technicians are installing subsystems at NASA’s rocket factory, Michoud Assembly Facility. The RL-10 engine for the Artemis II ICPS is complete and panels have been machined for its LH2 tank. In addition, panels are machined for the vehicle’s two adapters, with welding scheduled to begin in summer 2020. Flight hard-ware is also in production for the third SLS vehicle, with several booster motor segments cast. The pace of development on the EUS has increased, with the goal to complete Critical Design Review (CDR) in December 2020. Several EUS test rings have been machined at Michoud. The EUS is designed to exe-cute a variety of missions – human spaceflight, deployment of deep-space infra-structure, or high-C3 missions to the outer solar system – with crew and cargo configurations available beginning in the mid-2020s. The near-term goal for the nation’s powerful new space exploration asset, however, is to launch the Arte-mis program, and send the first woman and the next man to the lunar surface. At the Astrodynamics Specialist Conference, the SLS program will update the community on the progress of the initial Block 1 vehicle in final green run test-ing, integration and stacking. In addition, this paper will provide an update to the community on the manufacturing status of subsequent Block 1 and Block 1B vehicles.

Steve Creech↗