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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS2021

Magnetic Structure and Propagation of Two Interacting CMEs from the Sun to Saturn

One of the grand challenges in heliophysics is the characterization of coronal mass ejection (CME) magnetic structure and evolution from eruption at the Sun through heliospheric propagation. At present, the main difficulties are related to the lack of direct measurements of the coronal magnetic fi elds and the lack of 3D in-situ measurements of the CME body in interplanetary space. Nevertheless, the evolution of a CME magnetic structure can be followed using a combination of multi-point remote-sensing observations and multi-spacecraft in-situ measurements as well as modelling. Accordingly, we present in this work the analysis of two CMEs that erupted from the Sun on 28 April 2012. We follow their eruption and early evolution using remote-sensing data, fi nding indications of CME{CME interaction, and then analyse their interplanetary counterpart(s) using in-situ measurements at Venus, Earth, and Saturn. We observe a seemingly single flux rope at all locations, but find possible signatures of interaction at Earth, where high-cadence plasma data are available. Reconstructions of the in-situ flux ropes provide almost identical results at Venus and Earth but show greater discrepancies at Saturn, suggesting that the CME was highly distorted and/or that further interaction with nearby solar wind structures took place before 10 AU. This work highlights the difficulties in connecting structures from the Sun to the outer heliosphere and demonstrates the importance of multi-spacecraft studies to achieve a deeper understanding of the magnetic confi guration of CMEs.

Erika Palmerio↗
NASA NTRS1972

Mission analysis for design of a SEP multi-mission spacecraft.

Study of the multimission capability of a solar electric propulsion spacecraft. The study includes such factors as spacecraft constraints, payload variations with launch opportunity, propellant on-loading and off-loading requirements, and limitations in thrusting time, throttling range and steering. The study determined that a single spacecraft design, with P sub zero = 12 kW and I sub s = 3000 sec launched by a Titan IIIC or Titan IIID/Centaur can be used to conduct at least five diverse missions: Eros rendezvous, 1 AU out-of-ecliptic, Mercury orbiter, Jupiter flyby/probe, and Jupiter orbiter. Flight time and injection velocity vary as needed to achieve the desired payload capability. The mission analysis approach and results are presented.

Driver, J. M.↗
NASA NTRS1976

Economic analysis of standard interface modules for use with the multi-mission spacecraft. Volume 2: Appendices and drawings

The cost savings that could be obtained by the use of SIM to perform certain sensor electrical interfacing functions that were historically an integral part of the sensor are evaluated. Reduction in both the nonrecurring and recurring costs of this sensor interface hardware could be achieved through the use of SIM, and the study concludes that the development and use of certain power conditioning and data handling SIM units are economically justified.

Greenberg, J. S.↗
NASA NTRS1990

Multi-reactor configurations for multi-megawatt spacecraft power supplies

Several conceptual designs for a multimegawatt space nuclear power supply system were developed on the basis of hardware and technology from the existing multihundred kilowatt-class SP-100 reactor program. It is shown that net power outputs in the multimegawatt range can be achieved by using a modular multireactor configuration of several SP-100-derived nuclear power supplies. A variety of geometries were examined for their applicability to the multireactor configuration, showing that modular multireactor systems have the advantage of an increased redundancy in the power system, as compared with a single-reactor system, allowing higher reliabilities than those achievable with single-reactor systems. Results are presented on the Mars Cargo Mission analysis, showing that modularity allows the option of redeployment of power systems in Mars and facilitates refurbishment and turnaround of NEP transfer vehicles.

George, Jeffrey A.↗
NASA NTRS1992

Design of multi-mission spacecraft bus

This paper presents preliminary design of a multimission spacecraft bus for meteorological and communications payloads. The meteorological payload uses sun-synchronous circular orbit and the communications payload uses Molniya type orbit to provide communications for areas not covered by geosynchronous communications satellites. The launch vehicles are Pegasus for the meteorological payload and Taurus for the communications payload. The spacecraft bus uses three-axis stabilization consisting of a three reaction wheel system. The electric power system consists of single-axis tracking silicon solar array and Ni2 H2 batteries. The propulsion subsystem consists of six hydrazine thrusters and one propellant tank.

Agrawal, Brij N.↗
NASA NTRS1997

Series Connected Converter for Control of Multi-Bus Spacecraft Power Utility

The invention provides a power system using series connected regulators. Power from a source, such as a solar array, is processed through the regulators and provided to corresponding buses used to charge a battery and supply loads. The regulators employ a bypass loop around a DC-DC converter. The bypass loop connects a hot input of the converter to a return output, preferably though an inductor. Part of the current from the source passes through the bypass loop to the power bus. The converter bucks or boosts the voltage from the source to maintain the desired voltage at the bus. Thus, only part of the power is processed through the converter. The converter can also be used without the bypass loop to provide isolation. All of the converters can be substantially identical.

Beach, Raymond F.↗
NASA NTRS2007

Newton-Euler Dynamic Equations of Motion for a Multi-body Spacecraft

The Magnetospheric MultiScale (MMS) mission employs a formation of spinning spacecraft with several flexible appendages and thruster-based control. To understand the complex dynamic interaction of thruster actuation, appendage motion, and spin dynamics, each spacecraft is modeled as a tree of rigid bodies connected by spherical or gimballed joints. The method presented facilitates assembling by inspection the exact, nonlinear dynamic equations of motion for a multibody spacecraft suitable for solution by numerical integration. The building block equations are derived by applying Newton's and Euler's equations of motion to an "element" consisting of two bodies and one joint (spherical and gimballed joints are considered separately). Patterns in the "mass" and L'force" matrices guide assembly by inspection of a general N-body tree-topology system. Straightforward linear algebra operations are employed to eliminate extraneous constraint equations, resulting in a minimum-dimension system of equations to solve. This method thus combines a straightforward, easily-extendable, easily-mechanized formulation with an efficient computer implementation.

Stoneking, Eric↗
NASA NTRS2011

Cluster Observations of Multiple Dipolarization Fronts

We present Cluster observations of a series of dipolarization fronts (DF 1 to 6) at the central current sheet in Earth's magnetotail. The velocities of fast earthward flow following behind each DF 1-3, are comparable to the Alfven velocity, indicating that the flow bursts might have been generated by bursty reconnection that occurred tailward of the spacecraft. Based on multi-spacecraft timing analysis, DF normals are found to propagate mainly earthward at $160-335$ km/s with a thickness of 900-1500 km, which corresponds to the ion inertial length or gyroradius scale. Each DF is followed by significant fluctuations in the $x$ and $y$ components of the magnetic field whose peaks are found 1-2 minutes after the DF passage. These $(B_{x},B_{y} )$-fluctuations propagate dawnward (mainly) and earthward. Strongly enhanced field-aligned beams are observed coincidently with $(B_{x},B_{y})$ fluctuations, while an enhancement of cross-tail currents is associated with the DFs. From the observed pressure imbalance and flux-tube entropy changes between the two regions separated by the DF, we speculate that interchange instability destabilizes the DFs and causes the deformation of the mid-tail magnetic topology. This process generates significant field-aligned currents, and might power the auroral brightening in the ionosphere. However, this event is neither associated with the main substorm auroral breakup nor the poleward expansion, which might indicate that the observed multiple DFs have been dissipated before they reach the inner plasma sheet boundary.

Hwang, Kyoung-Joo↗
NASA NTRSDate not supplied

Advancing Autonomy in Distributed Space Systems: Insights From on-Orbit Testing with the Starling 1.0 Mission

Autonomous decision-making is crucial for enhancing mission effectiveness in Distributed Space Systems (DSS), particularly in multi-spacecraft operations where communication constraints and mission complexity pose challenges. The Distributed Spacecraft Autonomy (DSA) team at NASA’s Ames Research Center is advancing autonomy in DSS through five key technical areas: distributed resource and task management, reactive operations, system modeling and simulation, human-swarm interaction, and ad hoc network communications. The DSA experiment onboard the Starling 1.0 Mission showcases collaborative resource allocation for multi-point science data collection with four small spacecraft. Autonomy in decision-making is highlighted as a crucial factor for multi-spacecraft missions, enabling spacecraft to operate independently, reducing reliance on ground control. This capability is particularly significant for future deep-space missions, where communication delays and limited data transmission capacity make traditional command and control approaches impractical. This demonstration focuses on a GPS Channel Selection Experiment, leveraging emergent capabilities like "shared sampling" and "simultaneous sampling" to optimize channel selection across the spacecraft swarm. The experiment aims to capture ionospheric phenomena such as the Equatorial Ionization Anomaly and Polar Patches. The DSA system's autonomous reconfiguration ability is showcased, emphasizing its adaptability to natural phenomena without significant integration efforts. The GPS Channel Selection Experiment utilizes a dual-band GPS receiver to estimate plasma density in the ionosphere. Explorative and exploitative channel selections are employed based on the nature of observed phenomena. The performance of DSA algorithms is evaluated in terms of optimal channel allocations and responsiveness to changes in observed features. The DSA Flight Software utilizes the Core Flight System (cFS) framework, ensuring compatibility with the Starling 1.0 flight mission software. DSA showcases results from RTI’s Connext DDS Micro communication middleware, enabling message routing over the Ad-Hoc Network of Starling 1.0. This paper provides a comprehensive overview of the DSA experiment's initial results, emphasizing the advancements in autonomy for Distributed Space Systems and the successful collaboration with the Starling 1.0 mission.

Caleb Ashmore Adams↗
DOE OSTI2023

Physics of the Aurora: Laboratory Measurements of Electron Acceleration by Inertial Alfven Waves (Final Technical Report)

The physics of the aurora is one of the foremost unsolved problems of space physics. The mechanisms responsible for accelerating electrons that precipitate onto the ionosphere are not fully understood. For more than three decades, particle interactions with Alfven waves have been proposed as a possible means for accelerating electrons and generating auroras. Due to the limitations of spacecraft conjunction studies and other multi-spacecraft approaches, it is unlikely that it will ever be possible, through spacecraft observations alone, to confirm definitively the proposed electron acceleration mechanism by making simultaneous measurements of both the accelerated electrons and the inertial Alfven wave responsible for the acceleration. Here, we show laboratory measurements of the resonant transfer of energy from Alfven waves to electrons under conditions relevant to the auroral zone. Experiments are performed by launching Alfven waves and simultaneously recording the electron velocity distribution. Numerical simulations and analytical theory support that the measured energy transfer process produces accelerated electrons capable of reaching auroral energies. The experiments, theory, and simulations demonstrate a clear causal relationship between Alfven waves and accelerated electrons that directly cause auroras.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS2014

Approaching Solar Maximum 24 with Stereo-Multipoint Observations of Solar Energetic Particle Events

Since the beginning of the Solar Terrestrial Relations Observatory (STEREO) mission at the end of 2006, the two spacecraft have now separated by more than 130◦ degrees from the Earth. A 360-degree view of the Sun has been possible since February 2011, providing multipoint in situ and remote sensing observations of unprecedented quality. Combining STEREO observations with near-Earth measurements allows the study of solar energetic particle (SEP) events over a wide longitudinal range with minimal radial gradient effects. This contribution provides an overview of recent results obtained by the STEREO/IMPACT team in combination with observations by the ACE and SOHO spacecraft. We focus especially on multi-spacecraft investigations of SEP events. The large longitudinal spread of electron and 3He-rich events as well as unusual anisotropies will be presented and discussed.

observations↗
NASA NTRS2003

A Study of Learning Curve Impact on Three Identical Small Spacecraft

With an eye to the future strategic needs of NASA, the New Millennium Program is funding the Space Technology 5 (ST-5) project to address the future needs in the area of small satellites in constellation missions. The ST-5 project, being developed at Goddard Space Flight Center, involves the development and simultaneous launch of three small, 20-kilogram-class spacecraft. ST-5 is only a test drive and future NASA science missions may call for fleets of spacecraft containing tens of smart and capable satellites in an intelligent constellation. The objective of ST-5 project is to develop three such pioneering small spacecraft for flight validation of several critical new technologies. The ST-5 project team at Goddard Space Flight Center has completed the spacecraft design, is now building and testing the three flight units. The launch readiness date (LRD) is in December 2005. A critical part of ST-5 mission is to prove that it is possible to build these small but capable spacecraft with recurring cost low enough to make future NASA s multi- spacecraft constellation missions viable from a cost standpoint.

Chen, Guangming↗
NASA NTRSDate not supplied

The Distributed Spacecraft Autonomy (DSA)

NASA’s Distributed Spacecraft Autonomy (DSA) Project developed and demonstrated software to enhance multi-spacecraft mission adaptability, efficiently allocate tasks between spacecraft using ad-hoc networking, and enable human-swarm commanding of Distributed Space Missions.

Autonomy Distributed Space Missions↗
NASA NTRS2004

An Integrated Vision-Based System for Spacecraft Attitude and Topology Determination for Formation Flight Missions

With the space industry's increasing focus upon multi-spacecraft formation flight missions, the ability to precisely determine system topology and the orientation of member spacecraft relative to both inertial space and each other is becoming a critical design requirement. Topology determination in satellite systems has traditionally made use of GPS or ground uplink position data for low Earth orbits, or, alternatively, inter-satellite ranging between all formation pairs. While these techniques work, they are not ideal for extension to interplanetary missions or to large fleets of decentralized, mixed-function spacecraft. The Vision-Based Attitude and Formation Determination System (VBAFDS) represents a novel solution to both the navigation and topology determination problems with an integrated approach that combines a miniature star tracker with a suite of robust processing algorithms. By combining a single range measurement with vision data to resolve complete system topology, the VBAFDS design represents a simple, resource-efficient solution that is not constrained to certain Earth orbits or formation geometries. In this paper, analysis and design of the VBAFDS integrated guidance, navigation and control (GN&C) technology will be discussed, including hardware requirements, algorithm development, and simulation results in the context of potential mission applications.

Rogers, Aaron↗