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NASA NTRSDate not supplied

The MOCHII ISS National Laboratory: The First Spacecraft Based Scanning Electron Microscope

Introduction: Scanning electron microscopy (SEM) in concert with element identification by energy dispersive Xray (EDX) spectroscopy has become an indispensable tool in the analyses of extraterrestrial materials. Nevertheless, to-date, SEM-EDX instrumentation has remained purely in the purview of terrestrial laboratories due to their size, complexity, and operational requirements. However, in January 2022 a miniaturized SEM-EDX called MOCHII became the first successful space-based instrument of its kind, following its deployment onboard the International Space Station (ISS). It represents the culmination of nearly 40 years of technological development. We have performed an on-orbit study with MOCHII with the goal of evaluating its potential as the progenitor of a new generation of spacecraftbased instruments for use in future manned and robotic planetary exploration missions. Out goal has been to validate the on-orbit investigation of samples relevant to astromaterials and astrobiology. We have performed in-situ analyses on standards and a freshly fractured fragment of the Martian meteorite Allan Hills 84001 which was first analyzed, prior to launch, using an engineering MOCHII ground unit located at Johnson Space Center in Houston. Results of both imaging and compositional analyses substantiates the utility of remote SEM-EDX analyses in low Earth orbit (LEO).

Miniature Scanning Electron Microscope↗
NASA NTRS2009

Spacecraft Thermal Management

In the 21st century, the National Aeronautics and Space Administration (NASA), the Russian Federal Space Agency, the National Space Agency of Ukraine, the China National Space Administration, and many other organizations representing spacefaring nations shall continue or newly implement robust space programs. Additionally, business corporations are pursuing commercialization of space for enabling space tourism and capital business ventures. Future space missions are likely to include orbiting satellites, orbiting platforms, space stations, interplanetary vehicles, planetary surface missions, and planetary research probes. Many of these missions will include humans to conduct research for scientific and terrestrial benefits and for space tourism, and this century will therefore establish a permanent human presence beyond Earth s confines. Other missions will not include humans, but will be autonomous (e.g., satellites, robotic exploration), and will also serve to support the goals of exploring space and providing benefits to Earth s populace. This section focuses on thermal management systems for human space exploration, although the guiding principles can be applied to unmanned space vehicles as well. All spacecraft require a thermal management system to maintain a tolerable thermal environment for the spacecraft crew and/or equipment. The requirements for human rating and the specified controlled temperature range (approximately 275 K - 310 K) for crewed spacecraft are unique, and key design criteria stem from overall vehicle and operational/programatic considerations. These criteria include high reliability, low mass, minimal power requirements, low development and operational costs, and high confidence for mission success and safety. This section describes the four major subsystems for crewed spacecraft thermal management systems, and design considerations for each. Additionally, some examples of specialized or advanced thermal system technologies are presented, which may be enabling to future space missions never before attempted like a crewed mission to Mars.

Hurlbert, Kathryn Miller↗
NASA NTRS2012

Science Benefits of Onboard Spacecraft Navigation

Primitive bodies (asteroids and comets), which have remained relatively unaltered since their formation, are important targets for scientific missions that seek to understand the evolution of the solar system. Often the first step is to fly by these bodies with robotic spacecraft. The key to maximizing data returns from these flybys is to determine the spacecraft trajectory relative to the target body-in short, navigate the spacecraft- with sufficient accuracy so that the target is guaranteed to be in the instruments' field of view. The most powerful navigation data in these scenarios are images taken by the spacecraft of the target against a known star field (onboard astrometry). Traditionally, the relative trajectory of the spacecraft must be estimated hours to days in advance using images collected by the spacecraft. This is because of (1)!the long round-trip light times between the spacecraft and the Earth and (2)!the time needed to downlink and process navigation data on the ground, make decisions based on the result, and build and uplink instrument pointing sequences from the results. The light time and processing time compromise navigation accuracy considerably, because there is not enough time to use more accurate data collected closer to the target-such data are more accurate because the angular capability of the onboard astrometry is essentially constant as the distance to the target decreases, resulting in better "plane-of- sky" knowledge of the target. Excellent examples of these timing limitations are high-speed comet encounters. Comets are difficult to observe up close; their orbits often limit scientists to brief, rapid flybys, and their coma further restricts viewers from seeing the nucleus in any detail, unless they can view the nucleus at close range. Comet nuclei details are typically discernable for much shorter durations than the roundtrip light time to Earth, so robotic spacecraft must be able to perform onboard navigation. This onboard navigation can be accomplished through a self- contained system that by eliminating light time restrictions dramatically improves the relative trajectory knowledge and control and subsequently increases the amount of quality data collected. Flybys are one-time events, so the system's underlying algorithms and software must be extremely robust. The autonomous software must also be able to cope with the unknown size, shape, and orientation of the previously unseen comet nucleus. Furthermore, algorithms must be reliable in the presence of imperfections and/or damage to onboard cameras accrued after many years of deep-space operations. The AutoNav operational flight software packages, developed by scientists at the Jet Propulsion Laboratory (JPL) under contract with NASA, meet all these requirements. They have been directly responsible for the successful encounters on all of NASA's close-up comet-imaging missions (see Figure !1). AutoNav is the only system to date that has autonomously tracked comet nuclei during encounters and performed autonomous interplanetary navigation. AutoNav has enabled five cometary flyby missions (Table!1) residing on four NASA spacecraft provided by three different spacecraft builders. Using this software, missions were able to process a combined total of nearly 1000 images previously unseen by humans. By eliminating the need to navigate spacecraft from Earth, the accuracy gained by AutoNav during flybys compared to ground-based navigation is about 1!order of magnitude in targeting and 2!orders of magnitude in time of flight. These benefits ensure that pointing errors do not compromise data gathered during flybys. In addition, these benefits can be applied to flybys of other solar system objects, flybys at much slower relative velocities, mosaic imaging campaigns, and other proximity activities (e.g., orbiting, hovering, and descent/ascent).

Autonomy↗
NASA NTRS2004

NASA's In-Space Propulsion Technology Program: Overview and Update

NASA's In-Space Propulsion Technology Program is investing in technologies that have the potential to revolutionize the robotic exploration of deep space. For robotic exploration and science missions, increased efficiencies of future propulsion systems are critical to reduce overall life-cycle costs and, in some cases, enable missions previously considered impossible. Continued reliance on conventional chemical propulsion alone will not enable the robust exploration of deep space - the maximum theoretical efficiencies have almost been reached and they are insufficient to meet needs for many ambitious science missions currently being considered. The In-Space Propulsion Technology Program s technology portfolio includes many advanced propulsion systems. From the next-generation ion propulsion system operating in the 5- to 10-kW range to aerocapture and solar sails, substantial advances in spacecraft propulsion performance are anticipated. Some of the most promising technologies for achieving these goals ase the environment of space itself for energy and propulsion and are generically called 'propellantless' because they do not require onboard fuel to achieve thrust. Propellantless propulsion technologies include scientific innovations such as solar sails, electrodynamic and momentum transfer tethers, aeroassist, and aerocapture. This paper will provide an overview of both propellantless and propellant-based advanced propulsion technologies, as well as NASA s plans for advancing them as part of the In-Space Propulsion Technology Program.

Johnson, Les↗
NASA NTRS2004

NASA In-Space Propulsion Technology Program: Overview and Update

NASA's In-Space Propulsion Technology Program is investing in technologies that have the potential to revolutionize the robotic exploration of deep space. For robotic exploration and science missions, increased efficiencies of future propulsion systems are critical to reduce overall life-cycle costs and, in some cases, enable missions previously considered impossible. Continued reliance on conventional chemical propulsion alone will not enable the robust exploration of deep space - the maximum theoretical efficiencies have almost been reached and they are insufficient to meet needs for many ambitious science missions currently being considered. The In-Space Propulsion Technology Program's technology portfolio includes many advanced propulsion systems. From the next-generation ion propulsion system operating in the 5- to 10-kW range to aerocapture and solar sails, substantial advances in - spacecraft propulsion performance are anticipated. Some of the most promising technologies for achieving these goals use the environment of space itself for energy and propulsion and are generically called 'propellantless' because they do not require onboard fuel to achieve thrust. Propellantless propulsion technologies include scientific innovations such as solar sails, electrodynamic and momentum transfer.tethers, aeroassist and aerocapture. This paper will provide an overview of both propellantless and propellant-based advanced propulsion technologies, as well as NASA's plans for advancing them as part of the In-Space Propulsion Technology Program.

Johnson, Les↗
NASA NTRS2005

Trusted Autonomy for Space Flight Systems

NASA has long supported research on intelligent control technologies that could allow space systems to operate autonomously or with reduced human supervision. Proposed uses range from automated control of entire space vehicles to mobile robots that assist or substitute for astronauts to vehicle systems such as life support that interact with other systems in complex ways and require constant vigilance. The potential for pervasive use of such technology to extend the kinds of missions that are possible in practice is well understood, as is its potential to radically improve the robustness, safety and productivity of diverse mission systems. Despite its acknowledged potential, intelligent control capabilities are rarely used in space flight systems. Perhaps the most famous example of intelligent control on a spacecraft is the Remote Agent system flown on the Deep Space One mission (1998 - 2001). However, even in this case, the role of the intelligent control element, originally intended to have full control of the spacecraft for the duration of the mission, was reduced to having partial control for a two-week non-critical period. Even this level of mission acceptance was exceptional. In most cases, mission managers consider intelligent control systems an unacceptable source of risk and elect not to fly them. Overall, the technology is not trusted. From the standpoint of those who need to decide whether to incorporate this technology, lack of trust is easy to understand. Intelligent high-level control means allowing software io make decisions that are too complex for conventional software. The decision-making behavior of these systems is often hard to understand and inspect, and thus hard to evaluate. Moreover, such software is typically designed and implemented either as a research product or custom-built for a particular mission. In the former case, software quality is unlikely to be adequate for flight qualification and the functionality provided by the system is likely driven largely by the need to publish innovative work. In the latter case, the mission represents the first use of the system, a risky proposition even for relatively simple software.

Freed, Michael↗
NASA NTRS2016

Human Flight to Lunar and Beyond - Re-Learning Operations Paradigms

For the first time since the Apollo era, NASA is planning on sending astronauts on flights beyond LEO. The Human Space Flight (HSF) program started with a successful initial flight in Earth orbit, in December 2014. The program will continue with two Exploration Missions (EM): EM-1 will be unmanned and EM-2, carrying astronauts, will follow. NASA established a multi-center team to address the communications, and related tacking/navigation needs. This paper will focus on the lessons learned by the team designing the architecture and operations for the missions. Many of these Beyond Earth Orbit lessons had to be re-learned, as the HSF program has operated for many years in Earth orbit. Unlike the Apollo missions that were largely tracked by a dedicated ground network, the HSF planned missions will be tracked (at distances beyond GEO) by the DSN, a network that mostly serves robotic missions. There have been surprising challenges to the DSN as unique modern human spaceflight needs stretch the experience base beyond that of tracking robotic missions in deep space. Close interaction between the DSN and the HSF community to understand the unique needs (e.g. 2-way voice) resulted in a Concept of Operations (ConOps) that leverages both the deep space robotic and the Human LEO experiences. Several examples will be used to highlight the unique challenges the team faced in establishing the communications and tracking capabilities for HSF missions beyond Earth Orbit, including: Navigation. At LEO, HSF missions can rely on GPS devices for orbit determination. For Lunar-and-beyond HSF missions, techniques such as precision 2-way and 3-way Doppler and ranging, Delta-Difference-of-range, and eventually possibly on-board navigation will be used. At the same time, HSF presents a challenge to navigators, beyond those presented by robotic missions - navigating a dynamic/"noisy" spacecraft. Impact of latency - the delay associated with Round-Trip-Light-Time (RTLT). Imagine trying to have a 2-way discussion (audio or video) with an astronaut, with a 2-3 sec or more delay inserted (for lunar distances) or 20 minutes delay (for Mars distances). Balanced communications link. For robotic missions, there has been a heavy emphasis on higher downlink data rates, e.g. bringing back science data. Higher uplink data rates were of secondary importance, as uplink was used only to send commands (and occasionally small files) to the spacecraft. The ratio of downlink-to-uplink data rates was often 10:1 or more. For HSF, a continuous forward link is established and rates for uplink and downlink are more similar.

Kenny, Edward (Ted)↗
NASA NTRS2016

Commercial Application of In-Space Assembly

In-Space assembly (ISA) expands the opportunities for cost effective emplacement of systems in space. Currently, spacecraft are launched into space and deploy into their operational configuration through a carefully choreographed sequence of operations. The deployment operation dictates the arrangement of the primary systems on the spacecraft, limiting the ability to take full advantage of launch vehicles volume and mass capability. ISA enables vastly different spacecraft architectures and emplacement scenarios to be achieved, including optimal launch configurations ranging from single launch and assembly to on-orbit aggregation of multiple launches at different orbital locations and times. The spacecraft can be visited at different orbital locations and times to effect expansion and maintenance of an operational capability. To date, the primary application of ISA has been in large programs funded by government organizations, such as the International Space Station. Recently, Space Systems Loral (SSL) led a study funded by the Defense Advanced Research Projects Agency (DARPA), called Dragonfly, to investigate the commercial applicability and economic advantages of ISA. In the study, it was shown that ISA enables SSL to double the capability of a commercial satellite system by taking advantage of alternate packaging approaches for the reflectors. The study included an ultra-light-weight robotic system, derived from Mars manipulator designs, to complete assembly of portions of the antenna system using a tool derived from DARPA orbital express and National Aeronautics and Space Administration (NASA) automated structural assembly experience. The mechanical connector that enables robotic ISA takes advantage of decades of development by NASA from the 1970's to 1980's during the Space Station Freedom program, the precursor to the ISS. The mechanical connector was originally designed for rapid astronaut assembly while also providing a high quality structural connection with linear load deflection response. The paper will discuss the business case for ISA, the general approach taken to exploit on-orbit assembly in the GEO communication satellite market, and the concept of operations associated with the ISA approach, thus laying the foundation for ISA to become an accepted operational approach for commercial in-space operations.

Lymer, John↗
NASA NTRS2016

Current Design Criteria for MMOD Impact of Metallic Pressurized Tanks

Most spacecraft have at least one pressurized vessel on board. For robotic spacecraft, it is usually a liquid propellant tank or battery. For human spacecraft, there are also pressurized living quarters and life-support systems. One of the design considerations of such spacecraft is the possible damage that might occur in the event of an on-orbit impact by a micrometeoroid or orbital debris (MMOD) particle. While considerable energy and effort has been expended in the study of the response of nonpressurized spacecraft components to these kinds of impacts, relatively few studies have been conducted on the pressurized elements of such spacecraft. In addition, the design criteria currently used by the National Aeronautics and Space Administration (NASA) for pressurized tanks operating in the MMOD environment have not been tested or scrutinized since they were first proposed nearly 45 years ago. This paper reviews current NASA design criteria for pressurized vessels and offers suggestions for next steps in their further development.

orbital debris↗
NASA NTRS1993

The instant sequencing task: Toward constraint-checking a complex spacecraft command sequence interactively

Robotic spacecraft are controlled by sets of commands called 'sequences.' These sequences must be checked against mission constraints. Making our existing constraint checking program faster would enable new capabilities in our uplink process. Therefore, we are rewriting this program to run on a parallel computer. To do so, we had to determine how to run constraint-checking algorithms in parallel and create a new method of specifying spacecraft models and constraints. This new specification gives us a means of representing flight systems and their predicted response to commands which could be used in a variety of applications throughout the command process, particularly during anomaly or high-activity operations. This commonality could reduce operations cost and risk for future complex missions. Lessons learned in applying some parts of this system to the TOPEX/Poseidon mission will be described.

Horvath, Joan C.↗
NASA NTRSDate not supplied

The first 300 sols of the SHERLOC investigation on the Mars 2020 rover

The Mars2020 mission is NASA’s latest flagship mission to Mars. The spacecraft launched in July 2020, and landed in Jezero crater on February 18, 2021 at the Octavia Butler Landing site. The rocks and sediments of Jezero crater have been argued to have preserved records of past, potentially habitable environments. The mission is characterizing the field site by analyzing chemistry, looking for organics and searching for potential biosignatures. The Scanning Habitable Environments with Ra-man and Luminescence for Organics and Chemicals (SHERLOC) is a robotic arm mounted instrument. SHERLOC combines imaging with UV resonance Raman and native deep UV fluorescence spectroscopy to identify potential biosignatures and understand the aqueous history of the Jezero Region. WATSON (Wide Angle Topographic Sensor for Operations and eNgineering), a refight of the Mars Hand Lens Imager (MAHLI) on the Curiosity rover is capable of color imaging over a wide range of resolutions (from infinity to 13.1 micron/pixel) and is used for both science and engineering. A second imager, the Autofocusing Con-textual Imager (ACI), produces gray scale images at 10.1 micron/pixel resolution at a 48 mm range.

A. E. Murphy↗
NASA NTRS2010

In Situ Biological Contamination Studies of the Moon: Implications for Planetary Protection and Life Detection Missions

NASA and ESA have outlined visions for solar system exploration that will include a series of lunar robotic precursor missions to prepare for, and support a human return to the Moan, and future human exploration of Mars and other destinations, including possibly asteroids. One of the guiding principles for exploration is to pursue compelling scientific questions about the origin and evolution of life. The search for life on objects such as Mars will require careful operations, and that all systems be sufficiently cleaned and sterilized prior to launch to ensure that the scientific integrity of extraterrestrial samples is not jeopardized by terrestrial organic contamination. Under the Committee on Space Research's (COSPAR's) current planetary protection policy for the Moon, no sterilization procedures are required for outbound lunar spacecraft, nor is there a different planetary protection category for human missions, although preliminary C SPAR policy guidelines for human missions to Mars have been developed. Future in situ investigations of a variety of locations on the Moon by highly sensitive instruments designed to search for biologically derived organic compounds would help assess the contamination of the Moon by lunar spacecraft. These studies could also provide valuable "ground truth" data for Mars sample return missions and help define planetary protection requirements for future Mars bound spacecraft carrying life detection experiments. In addition, studies of the impact of terrestrial contamination of the lunar surface by the Apollo astronauts could provide valuable data to help refine future: Mars surface exploration plans for a human mission to Mars.

Glavin, Daniel P.↗
NASA NTRS2010

26th Space Simulation Conference Proceedings. Environmental Testing: The Path Forward

Topics covered include: A Multifunctional Space Environment Simulation Facility for Accelerated Spacecraft Materials Testing; Exposure of Spacecraft Surface Coatings in a Simulated GEO Radiation Environment; Gravity-Offloading System for Large-Displacement Ground Testing of Spacecraft Mechanisms; Microscopic Shutters Controlled by cRIO in Sounding Rocket; Application of a Physics-Based Stabilization Criterion to Flight System Thermal Testing; Upgrade of a Thermal Vacuum Chamber for 20 Kelvin Operations; A New Approach to Improve the Uniformity of Solar Simulator; A Perfect Space Simulation Storm; A Planetary Environmental Simulator/Test Facility; Collimation Mirror Segment Refurbishment inside ESA s Large Space; Space Simulation of the CBERS 3 and 4 Satellite Thermal Model in the New Brazilian 6x8m Thermal Vacuum Chamber; The Certification of Environmental Chambers for Testing Flight Hardware; Space Systems Environmental Test Facility Database (SSETFD), Website Development Status; Wallops Flight Facility: Current and Future Test Capabilities for Suborbital and Orbital Projects; Force Limited Vibration Testing of JWST NIRSpec Instrument Using Strain Gages; Investigation of Acoustic Field Uniformity in Direct Field Acoustic Testing; Recent Developments in Direct Field Acoustic Testing; Assembly, Integration and Test Centre in Malaysia: Integration between Building Construction Works and Equipment Installation; Complex Ground Support Equipment for Satellite Thermal Vacuum Test; Effect of Charging Electron Exposure on 1064nm Transmission through Bare Sapphire Optics and SiO2 over HfO2 AR-Coated Sapphire Optics; Environmental Testing Activities and Capabilities for Turkish Space Industry; Integrated Circuit Reliability Simulation in Space Environments; Micrometeoroid Impacts and Optical Scatter in Space Environment; Overcoming Unintended Consequences of Ambient Pressure Thermal Cycling Environmental Tests; Performance and Functionality Improvements to Next Generation Thermal Vacuum Control System; Robotic Lunar Lander Development Project: Three-Dimensional Dynamic Stability Testing and Analysis; Thermal Physical Properties of Thermal Coatings for Spacecraft in Wide Range of Environmental Conditions: Experimental and Theoretical Study; Molecular Contamination Generated in Thermal Vacuum Chambers; Preventing Cross Contamination of Hardware in Thermal Vacuum Chambers; Towards Validation of Particulate Transport Code; Updated Trends in Materials' Outgassing Technology; Electrical Power and Data Acquisition Setup for the CBER 3 and 4 Satellite TBT; Method of Obtaining High Resolution Intrinsic Wire Boom Damping Parameters for Multi-Body Dynamics Simulations; and Thermal Vacuum Testing with Scalable Software Developed In-House.

Packard, Edward A.↗
NASA NTRS1993

NSSDC data listing

This document identifies, in a highly summarized way, all the data held at the NSSDC. These data cover astrophysics and astronomy, solar and space physics, planetary and lunar, and Earth science disciplines. They are primarily, but not exclusively, from past and ongoing NASA spaceflight missions. We first identify all the data electronically available through NSSDC's principal online (magnetic disk-based) and nearline (robotics jukebox-based) systems, and then those data available on CDROM's. Finally, we identify all NSSDC-held data, the majority of which are still offline on magnetic tape, film, etc., but including the electronically accessible and CD-ROM resident data of earlier sections. These comprehensive identifications are in the form of two listings, one for the majority of NSSDC-held data sets resulting from individual instruments flown on individual spacecraft, and the other listing for the remainder of NSSDC-held data sets which do not adhere to this spacecraft/experiment/dataset hierarchy. The latter listing is presented in two parts, one for the numerous source catalogs of the NSSDC-operated Astronomical Data Center, and the other for the remainder. Access paths to all these data, and to further information about each, are also given in the related sections of this Data Listing. Note that this document is a companion to the electronically accessible information files (in particular, the NASA Master Directory) at NSSDC which also identify NSSDC-resident (and other) data.

Horowitz, Richard↗
NASA NTRS2012

Benefits of a Single-Person Spacecraft for Weightless Operations

Historically, less than 20 percent of crew time related to extravehicular activity (EVA) is spent on productive external work. For planetary operations space suits are still the logical choice; however for safe and rapid access to the weightless environment, spacecraft offer compelling advantages. FlexCraft, a concept for a single-person spacecraft, enables any-time access to space for short or long excursions by different astronauts. For the International Space Station (ISS), going outside is time-consuming, requiring pre-breathing, donning a fitted space suit, and pumping down an airlock. For each ISS EVA this is between 12.5 and 16 hours. FlexCraft provides immediate access to space because it operates with the same cabin atmosphere as its host. Furthermore, compared to the space suit pure oxygen environment, a mixed gas atmosphere lowers the fire risk and allows use of conventional materials and systems. For getting to the worksite, integral propulsion replaces hand-over-hand translation or having another crew member operate the robotic arm. This means less physical exertion and more time at the work site. Possibly more important, in case of an emergency, FlexCraft can return from the most distant point on ISS in less than a minute. The one-size-fits-all FlexCraft means no on-orbit inventory of parts or crew time required to fit all astronauts. With a shirtsleeve cockpit, conventional displays and controls are used, there is no suit trauma and because the work is not strenuous, no rest days are required. Furthermore, there is no need to collect hand tools because manipulators are equipped with force multiplying end-effectors that can deliver the precise torque for the job. FlexCraft is an efficient solution for asteroid exploration allowing all crew to use one vehicle with no risk of contamination. And, because FlexCraft is a vehicle, its design offers better radiation and micro-meteoroid protection than space suits.

Griffin, Brand Norman↗
NASA NTRS2012

The Keys to Successful Extended Missions

Many of NASA's successful missions of robotic exploration have gone on to highly productive mission extensions, from Voyager, Magellan, Ulysses, and Galileo, to the Mars Exploration Rovers Spirit and Opportunity, a variety of Mars orbiters, Spitzer, Deep Impact / EPOXI, and Cassini. These missions delivered not only a high science return during their prime science phase, but a wealth of opportunities during their extensions at a low incremental cost to the program. The success of such mission extensions can be traced to demonstration of new and unique science achievable during the extension; reduction in cost without significant increase in risk to spacecraft health; close inclusion of the science community and approval authorities in planning; intelligent design during the development and prime operations phase; and well crafted and conveyed extension proposals. This paper discusses lessons learned collected from a variety of project leaders which can be applied by current and future missions to maximize their chances of approval and success.

mission lifetime↗
NASA NTRS2004

Miniature Robotic Spacecraft for Inspecting Other Spacecraft

A report discusses the Miniature Autonomous Extravehicular Robotic Camera (Mini AERCam)-- a compact robotic spacecraft intended to be released from a larger spacecraft for exterior visual inspection of the larger spacecraft. The Mini AERCam is a successor to the AERCam Sprint -- a prior miniature robotic inspection spacecraft that was demonstrated in a space-shuttle flight experiment in 1997. The prototype of the Mini AERCam is a demonstration unit having approximately the form and function of a flight system. The Mini AERCam is approximately spherical with a diameter of about 7.5 in. (.19 cm) and a weight of about 10 lb (.4.5 kg), yet it has significant additional capabilities, relative to the 14-in. (36-cm), 35-lb (16-kg) AERCam Sprint. The Mini AERCam includes miniaturized avionics, instrumentation, communications, navigation, imaging, power, and propulsion subsystems, including two digital video cameras and a high-resolution still camera. The Mini AERCam is designed for either remote piloting or supervised autonomous operations, including station keeping and point-to-point maneuvering. The prototype has been tested on an air-bearing table and in a hardware-in-the-loop orbital simulation of the dynamics of maneuvering in proximity to the International Space Station.

Fredrickson, Steven↗
NASA NTRSDate not supplied

The Comet Astrobiology Exploration Sample Return (CAESAR) Mission

The Comet Astrobiology Exploration Sample Return (CAESAR) mission will acquire and return to Earth for laboratory analysis a minimum of 80 grams of surface material from the nucleus of comet 67P/Chur-yumov-Gerasimenko (67P). CAESAR will characterize the surface region sampled, preserve the collected sample in a pristine state, and return evolved volatiles by capturing them in a separate gas reservoir. NASA Goddard Space Flight Center provides project management, systems engineering, safety and mission assurance, contamination control, mission operations, and many other important functions. Northrop Grumman Space Systems will build the spacecraft, based on Dawn mission heritage, which like CAESAR, uses solar electric propulsion. CAESAR was selected by for Phase A study in the New Frontiers 4 Competition and will be proposed to New Frontiers 5.Collection of a sample from the surface of comet 67P is facilitated by a set of cameras that together provide images to support sample site selection, perform optical navigation, and document the sample before, during, and after col-lection. The sample is collected at the end of an arm during a 5-second touch-and-go (TAG) maneuver with the Sample Acquisition System (SAS)designed by Honeybee Robotics for the surface properties of comet 67P observed by the Rosetta mission. After sample collection, and while the sample is still cold (< -80°C), the TAG Arm inserts the sample container into the Sample Containment System (SCS) mounted inside the Sample Return Capsule (SRC). The SCS is sealed, preventing the sample from escaping into space. The sample is slowly warmed inside the SCS to enable sublimation of volatiles, which are collected in the Gas Containment System (GCS), a passively cooled gas reservoir. Separating the volatiles from the solid sample protects the solid sample from alteration. Once all sublimated H2O is transferred to the GCS, the GCS is sealed to capture the volatile sit contains, and the SCS is vented to space to maintain the solid sample under vacuum. The SCS vent is closed before Earth entry to prevent atmospheric contamination. Detailed laboratory analyses of the sample from 67P will trace the history of volatile reservoirs, delineate the chemical pathways that led from simple interstellar species to complex molecules, constrain the evolution of the comet, and evaluate the role of comets in delivering water and prebiotic organics to the early Earth. CAESAR will achieve these goals by carrying out coordinated sample analyses that will link macroscopic properties of the comet with microscale mineralogy, chemistry, and isotopic studies of volatiles and solids. Most of the sample (≥75%) will be set aside for analyses by generations of scientists using continually advancing tools and methods, yielding an enduring scientific treasure that only sample return can provide. This presentation will review development conducted during NF4 Phase A and discuss the NF5 mission concept.

A G Hayes↗