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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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9 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Cassini Star Tracking and Identification Algorithms, Scene Simulation, and Testing

The Cassini mission will use autonomous star identification for initial attitude determination and a star tracking function for maintaining attitude. Because of the complexity of the StarID software, special software simulation tools were created to simulate the Stellar Reference Unit (SRU) output as a function of commands, spacecraft attitude, and star scene, and to allow the introduction of fault conditions. This paper gives the overview of the algorithm design and SRU simulation and a description of the simulation test results and a comparison with field test results obtained using the engineering model SRU.

Cassini↗
NASA NTRS1974

Description of the attitude control, guidance and navigation space replaceable units for automated space servicing of selected NASA missions

Control elements such as sensors, momentum exchange devices, and thrusters are described which can be used to define space replaceable units (SRU), in accordance with attitude control, guidance, and navigation performance requirements selected for NASA space serviceable mission spacecraft. A number of SRU's are developed, and their reliability block diagrams are presented. An SRU assignment is given in order to define a set of feasible space serviceable spacecraft for the missions of interest.

Chobotov, V. A.↗
NASA NTRS1996

Cassini Stellar Reference Unit: Performance Test Approach and Results

The Cassini Stellar Reference Unit (SRU) is the prime attitude determination sensor on the Cassini spacecraft...To ensure that the SRU will operate within specification for the entire mission, an extensive test program has been undertaken to characterize the SRU performance prior to launch and to quantify any expected performance degradation. Results from several eomplimentary test programs are presented and compared with pre-test performance predictions.

star↗
NASA NTRS1990

NASA Shuttle Logistics Depot (NSLD) - The application of ATE

The concept of the NASA Shuttle Logistics Depot (NSLD) developed for the Space Shuttle Orbiter Program is described. The function of the NSLD at Cape Canaveral is to perform the acceptance and diagnostic testing of the Shuttle's space-rated line-replaceable units and shop-replaceable units (SRUs). The NSLD includes a comprehensive electronic automatic test station, program development stations, and assorted manufacturing support equipment (including thermal and vibration test equipment, special test equipment, and a card SRU test system). The depot activities also include the establishment of the functions for manufacturing of mechanical parts, soldering, welding, painting, clean room operation, procurement, and subcontract management.

Simpkins, Lorenz G.↗
NASA NTRS2024

System Modeling of a Lunar Molten Regolith Electrolysis Plant

In-Situ Resource Utilization (ISRU) is the process of extracting local resources to produce commodities for propulsion, life support systems, and off-planet construction rather than transporting consumables from Earth. Molten Regolith Electrolysis (MRE) is a novel ISRU method of extracting oxygen gas and metal alloy from lunar regolith. The MRE process involves placing lunar regolith between two electrodes, through which current is passed, to melt the regolith and reduce the metal oxide constituents by direct electrolysis (e.g. FeO, SiO 2 , MgO, Al 2 O 3 ) into oxygen gas and metal alloys. The oxygen is liquefied and used as propellant for landers, while the metals (e.g. Ferro-alloys) are further processed and used in structural building materials and parts manufacturing. A system model was developed that accounted for the major processes of an MRE plant (from excavation of raw materials to storage of products) to assess the feasibility of a lunar MRE plant. The S ystem Engineering and Integration ( S E&I) I SRU M odeling and A nalysis (SIMA) team utilized its previously documented system sizing model, the Mission Analysis and Integration Tool (MAIT) as framework of the system model. MAIT uses MATLAB/Simulink to integrate subsystem models into a complete system model of the MRE plant. Total mass, volume, and power requirements were computed for numerous iterations of a MRE plant.

In-Situ Resource Utilization↗
NASA NTRS1996

An IRU for Cassini

The JPL Inertial Reference Unit (IRU) is the single most sophisticated assembly on the Cassini Spacecraft. At the core of the IRU is the state-of-the-art, Litton (formerly Delco) Hemispherical Resonator Gyroscope (HRG). Launched in October 1997, Cassini's trajectory utilizes gravity assist manuevers around Venus (twice), Earth, and Jupiter over a seven year period, arriving at Saturn in June 2004.

Cassini IRU Inertial Reference Unit attitude stabi↗
NASA NTRS1994

Cassini Tracking and Identification Architecture

The Cassini spacecraft will perform a detailed examination of the Saturnian system, including the release of a probe to study Saturn's largest satellite, Titan. The star tracker for the Cassini mission must provide accurate data during the entire flight including four years of measurement in a harsh radiation environment.

CCD base star camera Cassini star tracker Stellar ↗