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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 685 records · Page 38

Pointing and Tracking Concepts for Deep Space Missions

This paper summarizes part of a FY1998 effort on the design and development of an optical communications (Opcomm) subsystem for the Advanced Deep Space System Development (ADSSD) Project. This study was funded by the JPL X2000 program to develop an optical communications (Opcomm) subsystem for use in future planetary missions. The goal of this development effort was aimed at providing prototype hardware with the capability of performing uplink, downlink, and ranging functions from deep space distances. Such a system was envisioned to support future deep space missions in the Outer Planets/Solar Probe (OPSP) mission set such as the Pluto express and Europa orbiter by providing a significant enhancement of data return capability. A study effort was initiated to develop a flyable engineering model optical terminal to support the proposed Europa Orbiter mission - as either the prime telecom subsystem or for mission augmentation. The design concept was to extend the prototype lasercom terminal development effort currently conducted by JPL's Optical Communications Group. The subsystem would track the sun illuminated Earth at Europa and farther distances for pointing reference. During the course of the study, a number of challenging issues were found. These included thermo-mechanical distortion, straylight control, and pointing. This paper focuses on the pointing aspects required to locate and direct a laser beam from a spacecraft (S/C) near Jupiter to a receiving station on Earth.

Alexander, J. W.↗

SOLAR-B Mission Extreme Ultraviolet (EUV) Imaging Spectrometer (EIS) Instrument Components

This Monthly Progress Report covers the reporting period July 2001 of the Detailed Design and Development through Launch plus Thirty Days, Phase C/D, for selected components and subsystems of the Extreme Ultraviolet Imaging Spectrometer (EIS) instrument, hereafter referred to as EIS Instrument Components. This document contains the program status through the reporting period and forecasts the status for the upcoming reporting period.

Doschek, George A.↗

Solar-B Mission Extreme Ultraviolet (EUV) Imaging Spectrometer (EIS) Instrument Components

This Monthly Progress Report covers the reporting period August 2002 of the Detailed Design and Development through Launch plus Thirty Days, Phase C/D, for selected components and subsystems of the Extreme ultraviolet Imaging Spectrometer (EIS) instrument, hereafter referred to as EIS Instrument Components. This document contains the program status through the reporting period and forecasts the status for the upcoming reporting period.

Doschek, George A.↗

Status of NASA’s Deep Space Optical Communication Technology Demonstration

With NASA funding, the Deep Space Optical Communication (DSOC) Project at JPL is planning a system level technology demonstration of optical communications from deep space. A 22 cm diameter flight laser transceiver (FLT) is being developed for space flight. The FLT will be designed to transmit an average laser power of 4W at 1550 nm and receive a weak 1064 nm laser signal (> 100 femtowatts). Use of the Hale telescope at Palomar Mountain, CA, retrofitted with a photoncounting receiver to detect the downlink from space, is planned. The Optical Communication Telescope Laboratory (OCTL) at Table Mountain, CA will transmit a 1064 nm laser beacon to serve as a pointing reference for the FLT and support low-rate uplink data-rates. The DSOC FLT is part of the baseline payload for the Psyche mission spacecraft recently selected for flight by NASA, providing link demonstration opportunities during the mission cruise phase. Link demonstration opportunities at distances of approximately 0.1 to 2 astronomical units (AU) are expected. The DSOC system is being designed to support downlink data-rates of 0.2 to > 200 Mb/s and uplink data rates of approximately 1.6 kb/s. A status update of DSOC Project activities on flight and ground development will be summarized in this paper.

Biswas, Abhijit↗

Nano-Newton Electrostatic Force Actuators for Femto-Newton-Sensitive Measurements: System Performance Test in the LISA Pathfinder Mission

Electrostatic force actuation is a key component of the system of geodesic reference test masses (TM) for the LISA orbiting gravitational wave observatory and in particular for performance at low frequencies, below 1 mHz, where the observatory sensitivity is limited by stray force noise. The system needs to apply forces of order 10 −9 N while limiting fluctuations in the measurement band to levels approaching 10 −15 N=Hz 1/2 . We present here the LISA actuation system design, based on audio-frequency voltage carrier signals, and results of its in-flight performance test with the LISA Pathfinder test mission. In LISA, TM force actuation is used to align the otherwise free-falling TM to the spacecraft-mounted optical metrology system, without any forcing along the critical gravitational wave-sensitive interferometry axes. In LISA Pathfinder, on the other hand, the actuation was used also to stabilize the TM along the critical x axis joining the two TM, with the commanded actuation force entering directly into the mission’s main differential acceleration science observable. The mission allowed demonstration of the full compatibility of the electrostatic actuation system with the LISA observatory requirements, including dedicated measurement campaigns to amplify, isolate, and quantify the two main force noise contributions from the actuation system, from actuator gain noise and from low frequency “in band” voltage fluctuations. These campaigns have shown actuation force noise to be a relevant, but not dominant, noise source in LISA Pathfinder and have allowed performance projections for the conditions expected in the LISA mission.

M. Armanos↗

Evaluating Extravehicular Activity Access Options for a Lunar Surface Habitat

NASA’s upcoming return to the moon includes a plan for longer duration lunar missions that prioritize science and surface exploration. The current Artemis Base Camp reference proposes a Surface Habitat (SH) that will support 2 to 4 crewmembers with adequate capability for living and working for 30 days or more. An important aspect of the SH’s design will be its ability to support a high frequency of Extravehicular Activities (EVAs) for scientific purposes. There are multiple airlock designs that can support EVA access from inside the SH out to the lunar surface. This paper explores three unique options for EVA access: a traditional airlock, a suitlock, and a suitport-airlock.A traditional airlock is accessed by use of a hatch, crewmembers don and doff their EVA suits inside the airlock, and it must be depressurized and repressurized for every EVA. A suitlock is also depressurized and repressurized for every EVA but thesuits are donned through a suitport attached to the airlock bulkhead. A suitport-airlock is access through suitports that are attached to the airlock bulkhead as well, but the suitport-airlock stays in vacuum, and it does not have to be depressurized and repressurized for each EVA. This study also evaluated the use of an Airlock Airsave System in the cases of a traditional airlock and suitlock. This system captures a fraction of the airlock gas instead of venting all of the gas pre-EVA. The captured gas isthen used to partially repressurize the airlock post-EVA.In this study, each option is evaluated based on seven different areas of analysis. The metrics include overhead time for EVAs, dust mitigation, consumables for resupply mass, systems mass, system power, safety and mission assurances, and programmatic considerations. The EVA access options are evaluated and compared under each area of analysis. While the baseline case assumes the SH is at 8.2 psia, the authors also investigate the impact of a 10.2 psia habitat as an alternative in this analysis. Following the conclusion of the analysis, the authors recommend the usage of a Suitport-Airlock for Lunar SH missions and detail the reasoning behind the recommendation.

EVA↗

Design for pressure regulating components

The design development for Pressure Regulating Components included a regulator component trade-off study with analog computer performance verification to arrive at a final optimized regulator configuration for the Space Storable Propulsion Module, under development for a Jupiter Orbiter mission. This application requires the pressure regulator to be capable of long-term fluorine exposure. In addition, individual but basically identical (for purposes of commonality) units are required for separate oxidizer and fuel pressurization. The need for dual units requires improvement in the regulation accuracy over present designs. An advanced regulator concept was prepared featuring redundant bellows, all metallic/ceramic construction, friction-free guidance of moving parts, gas damping, and the elimination of coil springs normally used for reference forces. The activities included testing of actual size seat/poppet components to determine actual discharge coefficients and flow forces. The resulting data was inserted into the computer model of the regulator. Computer simulation of the propulsion module performance over two mission profiles indicated satisfactory minimization of propellant residual requirements imposed by regulator performance uncertainties.

Wichmann, H.↗

Enterprise Mission Integration for Artemis Lunar Missions

Mission integration is an iterative process by which a specific mission is formulated, refined, planned, and executed within the established vehicle(s), architecture, and ground systems design. Mission integration includes the people, vehicle(s) and ground hardware/software, products, processes, analyses, schedules, facilities, Certification of Flight Readiness, etc. The Artemis Mission Integration Task Team (MITT) developed a series of products and processes to support the complex mission integration across various Programs within the Artemis Mission Campaign (Orion, Space Launch Systems, Exploration Ground Systems, Gateway, Human Landing System, and Extravehicular Activity and Human Surface Mobility). The Moon to Mars (M2M) Program is referred to as ‘the enterprise’ as it includes both the M2M organization and the Programs supporting the Artemis Mission Campaign. Artemis Mission Integration has five phases: mission capability, mission definition, mission preparation, mission execution, and post-mission assessment. This paper focuses on one of the enterprise-level mission checkpoints as a kick-off to the Mission Preparation phase, the Mission Integration Review (MIR), which occurs 18-24 months prior to launch. The MIR helps to confirm the defined mission technical baseline is within the existing analyzed design envelope. Details are provided on the identification of dependencies, issues, or gaps for mission-specific objectives and requirements, as well as the definition of the analysis, training, mission execution products, facilities, and detailed supporting operations requirements. The MIR was held for both Artemis I and II and this paper aims to share with the aerospace community its value as we prepare for upcoming Artemis Missions.

Mary Anne Plaza↗

Evaluating Extravehicular Activity Access Options for a Lunar Surface Habitat

NASA’s upcoming return to the moon includes a plan for longer duration lunar missions that prioritize science and surface exploration. The current Artemis Base Camp reference proposes a Surface Habitat (SH) that will support 2 to 4 crewmembers with adequate capability for living and working for 30 days or more. An important aspect of the SH’s design will be its ability to support a high frequency of Extravehicular Activities (EVAs) for scientific purposes. There are multiple airlock designs that can support EVA access from inside the SH out to the lunar surface. This paper explores three unique options for EVA access: a traditional airlock, a suitlock, and a suitport-airlock. A traditional airlock is accessed by use of a hatch, crewmembers don and doff their EVA suits inside the airlock, and it must be depressurized and repressurized for every EVA. A suitlock is also depressurized and repressurized for every EVA but the suits are donned through a suitport attached to the airlock bulkhead. A suitport-airlock is accessed through suitports that are attached to the airlock bulkhead as well, but the suitport-airlock stays in vacuum, and it does not have to be depressurized and repressurized for each EVA. This study also evaluated the use of an Airlock Airsave System in the cases of a traditional airlock and suitlock. This system captures a fraction of the airlock gas instead of venting all of the gas pre-EVA. The captured gas is then used to partially repressurize the airlock post-EVA. In this study, each option is evaluated based on seven different areas of analysis. The metrics include overhead time for EVAs, dust mitigation, consumables for resupply mass, systems mass, system power, safety and mission assurances, and programmatic considerations. The EVA access options are evaluated and compared under each area of analysis. While the baseline case assumes the SH is at 8.2 psia, the authors also investigate the impact of a 10.2 psia habitat as an alternative in this analysis. Following the conclusion of the analysis, the authors recommend the usage of a Suitport-Airlock for Lunar SH missions and detail the reasoning behind the recommendation.

EVA↗

Performance of Cassini Reaction Wheel Friction Compensation Scheme During Spin Rate Zero-Crossing and Drag Spikes

Cassini uses reaction wheels to achieve the spacecraft pointing stability that is needed during imaging operations of several science instruments. The Cassini flight software makes inflight estimates of reaction wheel bearing drag torque and the reaction wheel controller uses these estimates to achieve a high level of spacecraft pointing stability. However, the Cassini drag torque estimator was designed to accurately track the bearing drag torque only in the steady state. When the physical drag torque changes abruptly (for example, during a reaction wheel spin rate reversal or when wheel bearings experienced drag spikes), the drag estimator will not be able to track the physical drag closely. This will lead to a degradation in the spacecraft pointing stability performance. For Cassini, this was not a problem because of the significant performance margin in pointing stability. However, for missions that have very challenging pointing stability requirements and that must perform well in the presence of frequent wheel rate reversals, alternative drag-compensating control schemes must be considered. To this end, alternative drag torque compensating control schemes (such as the adaptive model reference control scheme) are briefly reviewed in this paper. Selected design features used in these friction compensation schemes may be incorporated in reaction wheel controller design to improve the robustness of spacecraft pointing stability performance with regard to a wide range of reaction wheel drag torque anomalous behavior.

Lee, Allan Y↗

Commonality of flight control systems for support of European telecommunications missions

This paper is concerned with the presentation of mission-independent software systems that provide a common software platform to ground data systems for mission operations. The objectives of such common software platforms are to reduce the cost of the development of mission-dedicated software systems and to increase the level of reliability of the ground data systems for mission operations. In accordance with this objective, the Multi-Satellite Support System (MSSS) was developed at the European Space Operations Center (ESOC). Between 1975 and 1992, the MSSS provided support to 16 European Space Agency (ESA) missions, among them very demanding science missions such as GEOS, EXOSAT, and Giotto. The successful support of these missions proved the validity of the MSSS concept with its extended mission-independent platform. This paper describes the MSSS concept and focuses on the wide use of MSSS as a flight control system for geosynchronous telecommunications satellites. Reference is made to more than 15 telecommunications missions that are operated from Western Europe using flight control systems with an underlying MSSS concept, demonstrating the benefits of a commonly used software platform. Finally, the paper outlines the design of the new generation of flight control systems, which is being developed at ESOC for this decade, following a period of more than 15 years of MSSS support.

Debatin, Kurt↗

Navigational demands of low-level helicopter flight

The present study was designed to assess the verbal references to map, terrain, direction, and position, that navigators and pilots communicate during a simulated low-level flight. Two-person crews were asked to communicate normally while negotiating six short flight missions that varied widely in regard to map-terrain characteristics. Half of the crews performed the exercises with fixed, north-up maps and the other half used movable maps that were adjusted to maintain a track-up correspondence to the flight route. An analysis was performed to compare differences in crew communication patterns between map orientations, characteristics, and navigation tasks. The results showed differences in the frequency of communication across categories for map characteristics but not for map orientations or tasks. A difference in the proportion of communications between pilot and navigator occurred when crew were lost. Pilots communicated more than navigators when crews were lost and the reverse was true when crews were not lost. The results support and extend findings from a distance error performance analysis performed on the same flight missions.

Delzell, Susanne↗

Flight Dynamics Analysis Branch End of Fiscal Year 2004 Report

This report summarizes the major activities and accomplishments carried out by the Flight Dynamics Analysis Branch (FDAB), Code 595, in support of flight projects and technology development initiatives in Fiscal Year (FY) 2004. The report is intended to serve as a summary of the type of support carried out by the FDAB, as well as a concise reference of key accomplishments and mission experience derived from the various mission support roles. The primary focus of the FDAB is to provide expertise in the disciplines of flight dynamics including spacecraft navigation (autonomous and ground based); spacecraft trajectory design and maneuver planning; attitude analysis; attitude determination and sensor calibration; and attitude control subsystem (ACS) analysis and design. The FDAB currently provides support for missions and technology development projects involving NASA, other government agencies, academia, and private industry.

DeLion, Anne↗

Cassini tour navigation strategy

The Cassini-Huygens spacecraft was launched on October 15, 1997 as a joint NASA/ESA mission to explore Saturn. After a 7 year cruise the spacecraft will enter orbit around Saturn on 1 July 2004 for a 4 year investigation of the Saturnian system. The Cassini Navigation Team is responsible for designing the reference trajectory and conducting operations to realize this design. This paper describes the strategy for achieving project requirements, the characteristics of the Cassini navigation challenge, and the underlying assumptions.

Saturn↗

Flight Dynamics Analysis Branch End of Fiscal Year 2005 Report

This report summarizes the major activities and accomplishments carried out by the Flight Dynamics Analysis Branch (FDAB), Code 595, in support of flight projects and technology development initiatives in Fiscal Year (FY) 2005. The report is intended to serve as a summary of the type of support carried out by the FDAB, as well as a concise reference of key accomplishments and mission experience derived from the various mission support roles. The primary focus of the FDAB is to provide expertise in the disciplines of flight dynamics including spacecraft navigation (autonomous and ground based), spacecraft trajectory design and maneuver planning, attitude analysis, attitude determination and sensor calibration, and attitude control subsystem (ACS) analysis and design. The FDAB currently provides support for missions and technology development projects involving NASA, other government agencies, academia, and private industry.

Source record↗

Flight Dynamics Analysis Branch 2005 Technical Highlights

This report summarizes the major activities and accomplishments carried out by the Flight Dynamics Analysis Branch (FDAB), Code 595, in support of flight projects and technology development initiatives in Fiscal Year (FY) 2005. The report is intended to serve as a summary of the type of support carried out by the FDAB, as well as a concise reference of key accomplishments and mission experience derived from the various mission support roles. The primary focus of the FDAB is to provide expertise in the disciplines of flight dynamics including spacecraft navigation (autonomous and ground based); spacecraft trajectory design and maneuver planning; attitude analysis; attitude determination and sensor calibration; and attitude control subsystem (ACS) analysis and design. The FDAB currently provides support for missions and technology development projects involving NASA, other government agencies, academia, and private industry.

Source record↗

Enabling Mission Flexibility to Battery Driven Deep Space Endeavors With Generalized Battery-Health-Monitoring Using Physics-Based and Data-Driven Reduced-Order Models

The needs and requirements for an electrochemical energy storage for deep space exploration is well explored. It is often understood that different mission sites and environmental conditions require different battery chemistries or technologies. Additionally, various engineering solutions are deployed to overcome specific chemical challenges. One often overlooked need is the “health” monitoring of an electrochemical storage system. The term generalized health monitoring, as envisioned in this work, refers to the monitoring of various aspects such as electrode health, electrolyte health, reaction pathway health, cooling system health, sensor health, and BMS health [1]. Generalized health monitoring allows mission leads, engineers, and scientists to incorporate flexibility in mission designs, make on-the-fly mission changes, and extend the duration of science missions. Moreover, it enables automation and data-driven decision-making without compromising safety and performance. Recently, our group developed a hierarchy of thermal reduced-order models (TROM) by combining a physics-based modeling approach and data-driven model reduction techniques applied to flight data [2]. The resulting TROMs were found to be not only accurate but also identifiable from the flight data. Consequently, the coefficient of variance of the model parameters is small over the course of hundreds of flights, allowing for monitoring the parameter evolution trajectories as the battery ages and degrades. These parameters constitute the metrics of the generalized health of a battery. Monitoring their evolution allows such models to be used for anomaly detection and prognostics, improving early detection of abnormal behavior and thus enabling timely maintenance, longer battery life, and enhanced battery safety. For this presentation, the practicality of the thermal model will be validated on a pack of 14cells under various topology configurations such as 1S14P, 2P7S, 7S2P, and 1P14S. It is well known that manufacturing and non-uniform aging lead to variability in the performance of a cell, which is exacerbated by cell balancing during active load. Additionally, in extreme scenarios, the paramount objective is to complete the mission, regardless of the stresses on the battery. Topology-induced balancing issues further stress the battery. The goal of this study is to determine if the noise (identifiability) in the reduced-order thermal model parameters is sensitive to topology, cell spacing, cooling strategy, and manufacturing or age variability. The variability in cells is considered by assuming a multimodal distribution for microscopic parameters of a cell (such as porosity, tortuosity, reaction kinetics, volumetric thermal conductivity, and volumetric heat capacity). The compounded effect of manufacturing variability, topological selection, cooling strategies, and cell balancing ages each cell in a battery differently. The study aims to clarify whether the challenge in extracting maximum information depends on the minimum number of sensors or models used for data extraction.

Automation↗

Motor Qualification for Long-Duration Mars Missions

Qualification of motors for deep space under extreme thermal environments to be encountered during the Mars Science Laboratory (MSL) mission is required to verify the reliability and validate mission assurance requirements. The motor assembly must survive all ground operations, plus the nominal 670 Martian-day (or sol) mission that includes summer and winter seasons of the Mars environment. The motor assembly was tested and characterized under extreme temperature conditions with reference to hardware requirements. The motor assembly has been proved to be remarkably robust and displayed no sign of degradation due to the 3 X (three times per JPL design principles) thermal environmental exposure to the punishing Mars surface operations cycles. The motor characteristics obtained before, during, and post-test comparisons for the surface operations cycles are within measurement error of one another. The motors withstood/survived 2,010 extreme temperature cycles with a Delta T of 190 C deep temperature cycles, representing three times the expected thermal cycling exposure during the MSL surface operations. The qualification test hardware elements (A200 motor assembly, encoders, and resolver) have not shown any signs of degradation due to the PQV (Package Qualification and Verification) testing. The test hardware has demonstrated sufficient life to survive the deep thermal cycles associated with MSL mission surface operations for three lives.

Ramesham, Rajeshuni↗