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At least 955 records · Page 53

MSL EDL Entry Guidance using the Entry Terminal Point Controller

The Mars Science Laboratory will be the first Mars mission to attempt a guided entry with the objective of safely delivering the entry vehicle to a survivable parachute deploy state within 10 km of the pre-designated landing site. The Entry Terminal Point Controller guidance algorithm is derived from the final phase Apollo Command Module guidance and, like Apollo, modulates the bank angle to control range based on deviations in range, altitude rate, and drag acceleration from a reference trajectory. For application to Mars landers which must make use of the tenuous Martian atmosphere, it is critical to balance the lift of the vehicle to minimize the range while still ensuring a safe deploy altitude. An overview of the process to generate optimized guidance settings is presented, discussing improvements made over the last four years. Performance tradeoffs between ellipse size and deploy altitude will be presented, along with imposed constraints of entry acceleration and heating. Performance sensitivities to the bank reversal deadbands, heading alignment, attitude initialization error, and atmospheric delivery errors are presented. Guidance settings for contingency operations, such as those appropriate for severe dust storm scenarios, are evaluated.

Source record↗

Obtaining Public Opinion about sUAS Activity in an Urban Environment

The Unmanned Aircraft Systems (UAS) Traffic Management (UTM) research project has been developing and testing concept ideas for enabling small UAS (sUAS) operations in low altitude airspace (ground to 400 feet). To do this, a series of flight test demonstrations were organized over five years at seven test sites. Technology Capability Level-4 (TCL4), the most complex flight tests, were conducted in Texas, USA, during August 2019. This testing resulted in over 400 data collection flights using eight live rotorcraft, with nine flight crews flying pre-planned scenarios in the urban downtown and waterfront areas of Corpus Christi, Texas. Test scenarios were designed to include a variety of elements, including live and simulated vehicles, and personnel in many different roles, including flight crews and mission personnel. One group of people who did not have a role in the flight tests but will be affected by UAS operations as they become more ubiquitous, are the general public. What do the public think about sUAS operations in urban areas? In order to obtain a reference point that noted the public's view of the operations in the TCL4 demonstration, a short survey was developed and offered to members of the public who wished to comment on the sUAS activities they saw in their city during two weeks in August, 2019.Forty five people completed the online public opinion survey. Participants volunteered to take it, creating a self-selected sample. The survey included eleven questions that asked participants about their level of comfort and concerns with UAS activity; their knowledge of UAS operations; and, whether a traffic management system like UTM would increase their confidence in urban UAS activity. The general public in Corpus Christi showed a good level of knowledge of sUAS regulations, with almost half of their responses to the knowledge portion of the survey being correct. They expressed a moderate level of concern (x = 4.7 out of 7) at urban sUAS activity and, of those who cited a concern, the majority reported this was about privacy (54%), which are all responses in line with those reported in earlier research on public opinion. Views on UTM were mixed, with respondents indicating they thought the introduction of UTM will improve safety somewhat (5.2 out of 7) but it will also increase their concern a little (4.6 out of 7). This would indicate there needs to be more information and educational material about the UTM concept made available to the public with the aim to reduce public concerns about the system.

Caterina Grossi↗

Obtaining Public Opinion About sUAS Activity in an Urban Environment

The Unmanned Aircraft Systems (UAS) Traffic Management (UTM) research project has been developing and testing concept ideas for enabling small UAS (sUAS) operations in low altitude airspace (ground to 400 feet). To do this, a series of flight test demonstrations were organized over five years at seven test sites. Technology Capability Level-4 (TCL4), the most complex flight tests, were conducted in Texas, USA, during August 2019. This testing resulted in over 400 data collection flights using eight live rotorcraft, with nine flight crews flying pre-planned scenarios in the urban downtown and waterfront areas of Corpus Christi, Texas. Test scenarios were designed to include a variety of elements, including live and simulated vehicles, and personnel in many different roles, including flight crews and mission personnel. One group of people who did not have a role in the flight tests but will be affected by UAS operations as they become more ubiquitous, are the general public. What do the public think about sUAS operations in urban areas? In order to obtain a reference point that noted the public’s view of the operations in the TCL4 demonstration, a short survey was developed and offered to members of the public who wished to comment on the sUAS activities they saw in their city during two weeks in August, 2019. Forty five people completed the online public opinion survey. Participants volunteered to take it, creating a self-selected sample. The survey included eleven questions that asked participants about their level of comfort and concerns with UAS activity; their knowledge of UAS operations; and, whether a traffic management system like UTM would increase their confidence in urban UAS activity. The general public in Corpus Christi showed a good level of knowledge of sUAS regulations, with almost half of their responses to the knowledge portion of the survey being correct. They expressed a moderate level of concern (x = 4.7 out of 7) at urban sUAS activity and, of those who cited a concern, the majority reported this was about privacy (54%), which are all responses in line with those reported in earlier research on public opinion. Views on UTM were mixed, with respondents indicating they thought the introduction of UTM will improve safety somewhat (5.2 out of 7) but it will also increase their concern a little (4.6 out of 7). This would indicate there needs to be more information and educational material about the UTM concept made available to the public with the aim to reduce public concerns about the system.

UTM↗

The Plankton, Aerosol, Cloud, Ocean Ecosystem (Pace) Mission Overview: From Concept to Launch

Abstract for Technical Review: The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission is a strategic climate continuity mission that was defined in the 2010 document Responding to the Challenge of Climate and Environmental Change: NASA’s Plan for Climate-Centric Architecture for Earth Observations and Applications from Space (referred to as the “Climate Initiative”). Launched in February 2024, the PACE mission represents NASA’s next investment in ocean biology, clouds, and aerosol data records. PACE will extend the high quality ocean ecological, ocean biogeochemical, cloud, and aerosol particle data records begun by NASA in the 1990s, building on the exceptional heritages of the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS), the Moderate Resolution Imaging Spectroradiometer (MODIS), the Multi-angle Imaging SpectroRadiometer (MISR), and the Visible Infrared Imaging Radiometer Suite (VIIRS). NASA Headquarters directed the mission development and implementation to the NASA Goddard Space Flight Center (GSFC) with guidance to utilize a Design-to-Cost (DTC) process. Mission studies were conducted to define appropriate approaches within and across elements while maximizing science capabilities at a high cost confidence. Mission baseline requirements development is also embedded within the DTC process, as these requirements were not established at the onset of the mission concept development. The PACE project office at NASA’s GSFC was responsible for the satellite development, launch and commissioning. The NASA Headquarters PACE Program Science office is responsible for supporting the science data processing system and assembling competed community science teams, which includes field-based vicarious calibration and data product validation efforts to support the PACE Project Science team. The PACE observatory is comprised of three instruments, the Ocean Color Instrument (OCI) and two polarimeters, the Hyper-Angular Rainbow Polarimeter 2 (HARP2) and the Spectro-Polarimeter for Exploration (SPEXone) and the PACE spacecraft. The observatory has been commissioned and is performing on-orbit science data collection operations. Summary for Program: The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission is a strategic climate continuity mission that was defined in the 2010 document Responding to the Challenge of Climate and Environmental Change: NASA’s Plan for Climate-Centric Architecture for Earth Observations and Applications from Space (referred to as the “Climate Initiative”). Launched in February 2024 under the leadership of the NASA Goddard Space Flight Center (GSFC), the PACE mission represents NASA’s next investment in ocean biology, clouds, and aerosol data records. PACE will extend the high quality ocean ecological, ocean biogeochemical, cloud, and aerosol particle data records begun by NASA in the 1990s. The PACE observatory is comprised of the Ocean Color Instrument (OCI), the Hyper-Angular Rainbow Polarimeter 2 (HARP2) and the Spectro-Polarimeter for Exploration (SPEXone), along with the PACE spacecraft.

Robert H Estep, Jr↗

Mission Overview and Status from Concept to Launch

The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission is a strategic climate continuity mission that was defined in the 2010 document Responding to the Challenge of Climate and Environmental Change: NASA’s Plan for Climate-Centric Architecture for Earth Observations and Applications from Space (referred to as the “Climate Initiative”). Launched in February 2024, the PACE mission represents NASA’s next investment in ocean biology, clouds, and aerosol data records. PACE will extend the high quality ocean ecological, ocean biogeochemical, cloud, and aerosol particle data records begun by NASA in the 1990s, building on the exceptional heritages of the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS), the Moderate Resolution Imaging Spectroradiometer (MODIS), the Multi-angle Imaging SpectroRadiometer (MISR), and the Visible Infrared Imaging Radiometer Suite (VIIRS). NASA Headquarters directed the mission development and implementation to the NASA Goddard Space Flight Center (GSFC) with guidance to utilize a Design-to-Cost (DTC) process. Mission studies were conducted to define appropriate approaches within and across elements while maximizing science capabilities at a high cost confidence. Mission baseline requirements development is also embedded within the DTC process, as these requirements were not established at the onset of the mission concept development. The PACE project office at NASA’s GSFC was responsible for the satellite development, launch and commissioning. The NASA Headquarters PACE Program Science office is responsible for supporting the science data processing system and assembling competed community science teams, which includes field-based vicarious calibration and data product validation efforts to support the PACE Project Science team. The PACE observatory is comprised of three instruments, the Ocean Color Instrument (OCI) and two polarimeters, the Hyper-Angular Rainbow Polarimeter 2 (HARP2) and the Spectro-Polarimeter for Exploration (SPEXone) and the PACE spacecraft. The observatory has been commissioned and is performing on-orbit science data collection operations. Summary for Program: The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission is a strategic climate continuity mission that was defined in the 2010 document Responding to the Challenge of Climate and Environmental Change: NASA’s Plan for Climate-Centric Architecture for Earth Observations and Applications from Space (referred to as the “Climate Initiative”). Launched in February 2024 under the leadership of the NASA Goddard Space Flight Center (GSFC), the PACE mission represents NASA’s next investment in ocean biology, clouds, and aerosol data records. PACE will extend the high quality ocean ecological, ocean biogeochemical, cloud, and aerosol particle data records begun by NASA in the 1990s. The PACE observatory is comprised of the Ocean Color Instrument (OCI), the Hyper-Angular Rainbow Polarimeter 2 (HARP2) and the Spectro-Polarimeter for Exploration (SPEXone), along with the PACE spacecraft.

Robby Estep↗

Highly charged ions in a new era of high resolution X‐ray astrophysics

X‐ray astronomy and ground‐based atomic physics have a long history of fruitful collaboration: Sound understanding of the underlying atomic physics is the key to reliable interpretation of the spectra from celestial sources; conversely, astronomical spectra have been used to benchmark and advance atomic physics. This interplay is about to become even more important as we enter a new era of high‐resolution X‐ray astrophysics with large effective collection area. Although high‐resolution observations with the gratings on the Chandra and XMM‐Newton observatories continue to drive new science, upcoming planned and proposed missions will open up new discovery space in the near future that is currently challenging to access: high‐resolution spectroscopy on extended sources, in the Fe K band, and on short time scales. This review summarizes open questions in these areas and the design parameters for the Hitomi, XRISM, Athena, and Arcus observatories. The expected high quality of spectra taken with these observatories puts new constraints on the accuracy of atomic reference data required to take full advantage of the diagnostic potential of these spectra.

Hell, Natalie↗

Mars Science Laboratory Entry Guidance

The Mars Science Laboratory will be the first Mars mission to attempt a guided entry with the objective of safely delivering the entry vehicle to a survivable parachute deploy state within 12.5 km of the pre-designated parachute deploy coordinates. The Entry Terminal Point Controller guidance algorithm is derived from the final phase Apollo Command Module guidance and, like Apollo, modulates the bank angle to control range based on deviations in range, altitude rate, and drag acceleration from a reference trajectory. For application to Mars landers which must make use of the tenuous Martian atmosphere, it is critical to balance the lift of the vehicle to minimize the range while still ensuring a safe deploy altitude. An overview of the process to generate optimized guidance settings is presented, discussing improvements made over the last nine years. Performance tradeoffs between ellipse size and deploy altitude will be presented, along with imposed constraints of entry acceleration and heating. Performance sensitivities to the bank reversal deadbands, heading alignment, attitude initialization error, and entry delivery errors are presented.

Mendeck, Gavin F.↗

Highly Charged Ions in a New Era of High Resolution X-Ray Astrophysics

X‐ray astronomy and ground‐based atomic physics have a long history of fruitful collaboration: Sound understanding of the underlying atomic physics is the key to reliable interpretation of the spectra from celestial sources; conversely, astronomical spectra have been used to benchmark and advance atomic physics. This interplay is about to become even more important as we enter a new era of high‐resolution X‐ray astrophysics with large effective collection area. Although high‐resolution observations with the gratings on the Chandra and XMM‐Newton observatories continue to drive new science, upcoming planned and proposed missions will open up new discovery space in the near future that is currently challenging to access: high‐resolution spectroscopy on extended sources, in the Fe K band, and on short time scales. This review summarizes open questions in these areas and the design parameters for the Hitomi, XRISM, Athena, and Arcus observatories. The expected high quality of spectra taken with these observatories puts new constraints on the accuracy of atomic reference data required to take full advantage of the diagnostic potential of these spectra.

Natalie Hell↗

Spaceborne meteorological radar studies

Various radar designs and methods are studied for the estimation of rainfall parameters from space. An immediate goal is to support the development of the spaceborne radar that has been proposed for the Tropical Rain Measuring Mission (TRMM). The effort is divided into two activities: a cooperative airborne rain measuring experiment with the Radio Research Laboratory of Japan (RRL), and the modelling of spaceborne weather radars. An airborne rain measuring experiment was conducted at Wallops Flight Facility in 1985 to 1986 using the dual-wavelength radar/radiometer developed by RRL. The data are presently being used to test a number of methods that are relevant to spaceborne weather radars. An example is shown of path-averaged rain rates as estimated from three methods: the standard reflectivity rain rate method (Z-R), a dual-wavelength method, and a surface reference method. The results from the experiment shows for the first time the feasibility of using attenuation methods from space. The purposes of the modelling are twofold: to understand in a quantitative manner the relationships between a particular radar design and its capability for estimating precipitation parameters and to help devise and test new methods. The models are being used to study the impact of various TRMM radar designs on the accuracy of rain rate estimation as well as to test the performance of range-profiling algorithms, the mirror-image method, and some recently devised graphical methods for the estimation of the drop size distribution.

Meneghini, R.↗

Formations Near the Libration Points: Design Strategies Using Natural and Non-Natural Arcs

Space based observatory and interferometry missions, such as Terrestrial Planet Finder (TPF), Stellar Imager, and MAXIM, have sparked great interest in multi-spacecraft formation flight in the vicinity of the Sun-Earth/Moon (SEM) libration points. The initial phase of this research considered the formation keeping problem from the perspective of continuous control as applied to non-natural formations. In the present study, closer inspection of the flow, corresponding to the stable and center manifolds near the reference orbit, reveals some interesting natural relative motions as well as some discrete control strategies for deployment. A hybrid control strategy is also employed that combines both the natural formation dynamics with non-natural motions via input feedback linearization techniques.

Howell, K. C.↗

Interplanetary approach optical navigation with applications

The use of optical data from onboard television cameras for the navigation of interplanetary spacecraft during the planet approach phase is investigated. Three optical data types were studied: the planet limb with auxiliary celestial references, the satellite-star, and the planet-star two-camera methods. Analysis and modelling issues related to the nature and information content of the optical methods were examined. Dynamic and measurement system modelling, data sequence design, measurement extraction, model estimation and orbit determination, as relating optical navigation, are discussed, and the various error sources were analyzed. The methodology developed was applied to the Mariner 9 and the Viking Mars missions. Navigation accuracies were evaluated at the control and knowledge points, with particular emphasis devoted to the combined use of radio and optical data. A parametric probability analysis technique was developed to evaluate navigation performance as a function of system reliabilities.

Jerath, N.↗

PULSAUR 2

PULSAUR II is a sounding rocket experiment to investigate the pulsating aurora and related phenomena. The payload consists of a complementary set of instruments designed specifically to look at the pulsating aurora. The project will be managed by the Norwegian Space Center, with integration in Norway. The rocket is due for launch in January 1994 from the Andoya rocket range. Southwest Research Institute provided an electron sensor for this campaign. It is a 'top hat' electron spectrometer, referred to as AREA (Angle Resolving Energy Analyzer), and is based on the electron sensor developed for the CENTAUR mission.

Sharber, Jim↗

Power and Propulsion Element (PPE) Spacecraft Reference Trajectory Document

This document captures example reference trajectories for the PPE including a reference delivery orbit and orbit maintenance, an example cislunar orbit transfer and end-of-mission (EOM) disposal trajectory. The flexibility of electric propulsion offers, by its low thrust nature, multiple different trajectory options to transfer from one orbit to another. The trajectories captured in this document are representative examples of a low thrust transfer from the NRHO and to multiple cislunar orbits. This document provides a consistent set of data from mission design to be used in the design of the vehicle capable of flying the trajectory described. The data in this document will be used to create conference papers. In order to do so, we are ending this document through for external release.

Melissa L Mcguire↗

Improvements in the on-orbit response versus scan-angle characterization for the MODIS ocean color bands

On-orbit characterization of the response versus scan-angle (RVS) is one of the most challenging aspects of the reflective solar band (RSB) calibration for the MODIS instruments onboard the Terra and Aqua spacecraft. The degradation of the solar diffuser, together with the lack of onboard calibrators (OBCs) to cover additional scan angles, other than the one for the lunar observations, has resulted in the use of Earth view responses from the pseudo-invariant desert sites to track the on-orbit RVS changes. This approach has been implemented in Collection 6 (C6) and C6.1 for bands 1-4, 8 and 9 of both instruments and also band 10 of Terra MODIS. As the missions continue to operate over a decade beyond their designed life and the instrument optics continue to degrade, it is expected that the OBC based RVS currently applied to other bands, specifically the high-gain ocean bands, will be inadequate to maintain the long-term calibration stability. An interband calibration approach is formulated and implemented in this paper. The proposed approach relies on the use of a spectrally matching stable reference band to evaluate the long-term calibration stability of the high-gain ocean bands that typically saturate while viewing the selected calibration deserts. Results from this approach indicate a noticeable drift for Terra MODIS bands 11 and 12 whereas the Aqua bands continue to show excellent temporal stability. These results are consistent with the corrections derived by the NASA Ocean Biology Processing Group (OBPG) and are expected to have minimum impacts on the downstream science products.

MODIS↗

Architecture Options for Navigation in Cislunar Space for Human Landing System Vehicles

As part of architecture studies and insight analysis focused on requirements development into Human Landing System lunar architecture designs, multiple studies are underway to understand the sensitivities and options for achieving high precision landing on the lunar surface. The baseline approach utilizes a combination of multiple sensors to capture autonomous state observations of the lander with respect to the lunar surface. These systems are typically constrained in terms of operational altitudes by parameters such as onboard map size, camera focus, or sensor transmitted power (for altimeter observations). While these sensor suites do enable high precision landing, they are typically very complex and expensive. For a human-rated vehicle, fault detection algorithms are needed in addition to redundant sensors drive additional design complexity. Conversely, for these early missions, mass performance is key, so extended analysis is required to identify numbers of sensors, their ideal placement, and integration algorithms. A key part of this analysis is to help identify key sensor suites and options to help alleviate this design tension. An alternate approach is to take advantage and build out in-situ assets to allow for GPS-like navigation within the lunar regime through the use of navigation references or beacons. This can be achieved through the integration of navigation services into potential relays and pre-placed lunar surface assets. This research focuses on the capability of this infrastructure to support navigation in all areas of cislunar space such as: approach to the moon, in orbit around the moon, and ascent/descent operations to the surface. An augmented state linear covariance analysis (LinCov) and navigation state covariance analysis (NavCov) tools were used to assess a variety of navigation reference locations and how they can support vehicle operations through both understanding of state uncertainties and trajectory dispersions. This research helps to supplement existing studies focused on communication link analysis by providing additional insight into specific vehicle operational scenarios that are tied closely to potential Human Landing System scenarios. Key aspect of this analysis focus on the sensitivity to state knowledge of the references, the accuracy of inter-asset measurements, and placement in support of the various scenarios.

Evan J Anzalone↗

Future Homes in Space: Development of Concepts for Exploration Space Habitats

NASA’s Artemis campaign seeks to return humans to the moon and establish a sustained presence on the lunar surface. This session will emphasize how habitation capabilities on the moon and in cislunar space can potentially contribute to the sustainability objectives of Artemis. Habitable elements represent opportunities to enable longer duration stays, increase the number of crew members present, enhance science and utilization activities, drive technology development for future Mars exploration, perform analog missions, and fuel economic opportunities for US industry. Panelists include Paul Kessler (NASA Marshall Space Flight Center, deputy lead for lunar surface habitation); Andrew Choate (NASA Marshall Space Flight Center, Mars habitation lead); Krystofer Dudzinski (NASA Marshall Space Flight Center, a space architect within the MSFC Advanced Concepts Office); and Larry Toups (retired from NASA Johnson Space Center, currently an adjunct professor at University of Houston in space architecture). The panel is moderated by Tracie Prater (NASA Marshall Space Flight Center, Habitation Systems Development Office). The panel will begin with an overview of the history of habitation concepts and an academic perspective on general considerations in space habitat design (Larry Toups). Paul Kessler and Andrew Choate will introduce NASA’s principle of “architecting from the right” to help define objectives for Artemis missions, needs/characteristics, use cases, and functions (as published in the agency’s Architecture Definition Document) and provide perspective on how this principle informs habitation concept development work. NASA panelists will discuss key engineering challenges identified for developing, deploying, and operating habitable assets on the lunar surface and/or in deep space. These may include dust mitigation, outfitting of inflatable softgoods (for concepts which may use softgoods as a primary structural material), survival in lunar darkness, human health and performance considerations, maintenance/repair/sparing, and autonomy. These identified challenges represent risks for habitation systems development and relate closely to capability gaps identified by the agency. While the work of NASA Marshall Space Flight Center’s habitation development office is primarily focused on habitats which are launched from earth pre-integrated (referred to as Class I in the framework previously developed by NASA space architects Kennedy/Cohen) or launched from earth and deployed at the point of use (Class II), there is also extensive work in NASA, academia, and companies on constructed habitats, which would be built on a planetary surface using indigenous resources (Class III habitats). Panelist Krystopher Dudzinski will discuss potential evolutionary pathways from Class I and Class II habitats to Class III habitats, unique and common architectural challenges within each habitat class, and key gaps in implementing Class III habitats from an architectural perspective. NASA panelists and the moderator will also provide an overview of partnership opportunities and avenues for further engagement to advance habitation systems for the SpaceCom audience. NASA is currently developing notional concepts for a lunar surface habitat and Mars transit habitat, which will be discussed during this panel session and used as examples. These concepts represent options for habitation system design and are a point of departure. They do not represent a final plan or formal recommendation on the part of the agency. Based on the most recent analysis cycle, NASA’s lunar surface habitat (SH) concept nominally supports two crew members for 30 days, with the capacity to support four crew during a surge period where crew will swap between the SH and another surface asset, such as a pressurized rover. This example design has a metallic airlock for ingress/egress and the upper portion is an inflatable material system which serves as the habitation module. The notional interior of the habitat is a three-deck layout/configuration which supports all crew mission functions, including exercise, stowage, extravehicular activity (EVA), sleep, hygiene waste collection, maintenance and repair, and meal preparation. Under analysis assumptions for habitation, the Mars Transit Habitat (TH) concept would support four crew on an up to 1,200 day Mars mission. One option for the concept is to initially dock Transit Habitat at Gateway, where it can be used to increase the duration of crew stays in cislunar space and perform shakedown and analog missions prior to a Mars departure. One challenge in longer duration missions which involve both surface exploration and transit is understanding crew adaptation when transitioning between partial gravity and microgravity environments. TH at Gateway offers an opportunity to study this transition and in doing so reduce risks associated with future Mars exploration. Like lunar SH, the most recent analysis cycle concept of a Mars TH is a hybrid structure design, with a metallic section supporting EVAs, axial/radial docking, and Safe Haven capabilities, and an inflatable softgoods structure for the primary habitation function. Interior layouts to optimize crew usability and livability are currently under trade. The panel will include presentation material, but also seeks to engage the audience in a highly interactive conversation regarding the potential role for habitation in future exploration initiatives. Potential topics for discussion include the influence of the crew experience on habitation systems design and livability/usability considerations, the benefits of space habitation development in terrestrial applications, and challenges and opportunities in “feeding forward” lunar surface habitation systems development to Mars exploration.

space habitats↗

Aerocapture for manned Mars missions - Status and challenges

The current status for manned Mars missions and the associated challenges are summarized. Mission benefits are considered to increase with increasing Mars entry velocity. However, significant benefits accrue at moderate entry velocities between 7 and 8 km/sec, which is the realistically achievable range in view of g-limits and heating constraints. Blunt, low mass/drag coefficient (reference area) vehicles with L/Ds from 0.3 to 0.5 are found to be the preferred configurations, taking into account their adequate control authority and good payload packaging characteristics. The overall design characteristics of Mars aerocapture vehicles can be established with good confidence, using flight and ground test data and the state-of-the-art flow field analysis techniques. The principal challenges are identified as follows: to refine the knowledge of the Martian atmosphere in order to reduce design conservatism, to extend present stagnation region heating analyses to the entire vehicle forebody, and to develop reflective low-wall-catalycity TPS systems for enabling reusable vehicles.

Walberg, Gerald D.↗

Common lunar lander

This report focuses on the reference lander design developed at the Johnson Space Center, describing a small lunar soft lander with the capability to soft land about 64 kilograms of payload at any lunar latitude and longitude. The Artemis lander is a sun-pointing, three-axis vehicle that contributes to the translunar injection burn and performs the lunar orbit insertion, deorbit, descent and landing maneuvers with a single liquid bipropellant lander stage. Attention is given to mission profile and performance, the guidance, navigation and control subsystem, the propulsion subsystem, and the flight data subsystem.

Bailey, S.↗