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Results for “orbital operation requirements”

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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Electric propulsion

Electric propulsion (EP) is an attractive option for unmanned orbital transfer vehicles (OTV's). Vehicles with solar electric propulsion (SEP) could be used routinely to transport cargo between nodes in Earth, lunar, and Mars orbit. Electric propulsion systems are low-thrust, high-specific-impulse systems with fuel efficiencies 2 to 10 times the efficiencies of systems using chemical propellants. The payoff for this performance can be high, since a principal cost for a space transportation system is that of launching to low Earth orbit (LEO) the propellant required for operations between LEO and other nodes. Several aspects of electric propulsion, including candidate systems and the impact of using nonterrestrial materials, are discussed.

Garrison, Philip W.↗
NASA NTRS2018

GPM Orbital Maintenance Planning and Operations in Low Solar Activity Environment

The orbital maintenance operations of the GPM Core Observatory was predicted to have routine drag makeup maneuvers to maintain the mission orbit. The maneuver frequency and estimated fuel usage calculated prelaunch were very comparable to the actual values observed after launch for the first two years. However, when the solar minimum was being entered, instead of seeing the need for less frequent station keeping maneuvers the operations team had to adjust the maneuver plan operations in order to maintain orbit requirements during the low atmospheric drag period predicted to last as long as 2021. This paper will provide the original plan, requirements and restriction, and the plan changes that were made to adjust to this condition. The document will also discuss lessons learned.

flight dynamics↗
NASA NTRS2018

GPM Orbital Maintenance Planning and Operations in Low Solar Activity Environment

The orbital maintenance operations of the GPM Core Observatory was predicted to have routine drag makeup maneuvers to maintain the mission orbit. The maneuver frequency and estimated fuel usage calculated prelaunch were very comparable to the actual values observed after launch for the first two years. However, when the solar minimum was being entered, instead of seeing the need for less frequent station keeping maneuvers the operations team had to adjust the maneuver plan operations in order to maintain orbit requirements during the low atmospheric drag period predicted to last as long as 2021.

flight dynamics↗
NASA NTRS1977

Formulation of consumables management models. Guidelines for the development of consumables subsystem redlines for advanced spacecraft

Techniques developed for determining the safe operating range or condition of past space programs are inadequate to support requirements of highly repetitive and routine earth orbit operations of advanced spacecraft systems. General concepts are presented for establishing maximum and minimum limits (redlines) for the consumables subsystems of the space shuttle orbiter. Implementation of a redline status subprocessor is recommended as a substitute for methods employed in past programs. The algorithms developed are amenable for use in the Mission Control Center, the launch processing system, and the space shuttle onboard computer.

Zamora, M. A.↗
NASA NTRS1985

Primary propulsion of electrothermal, ion and chemical systems for space-based radar orbit transfer

An orbit transfer mission concept has been studied for a Space-Based Radar (SBR) where 40 kW required for radar operation is assumed available for orbit transfer propulsion. Arcjet, pulsed electrothermal (PET), ion, and storable chemical systems are considered for the primary propulsion. Transferring two SBR per shuttle flight to 1112 km/60 deg using electrical propulsion systems offers an increased payload at the expense of increased trip time, up to 2000 kg each, which may be critical for survivability. Trade offs between payload mass, transfer time, launch site, inclination, and height of parking orbits are presented.

Wang, S. Y.↗
NASA NTRS1985

Primary propulsion of electrothermal, ion, and chemical systems for space-based radar orbit transfer

An orbit transfer mission concept has been studied for a Space-Based Radar (SBR) where 40 kW required for radar operation is assumed available for orbit transfer propulsion. Arcjet, pulsed electrothermal (PET), ion, and storable chemical systems are considered for the primary propulsion. Transferring two SBR per shuttle flight to 1112 km/60 deg using eiectrical propulsion systems offers an increased payload at the expense of increased trip time, up to 2000 kg each, which may be critical for survivability. Trade offs between payload mass, transfer time, launch site, inclination, and height of parking orbits are presented.

Wang, S.-Y.↗
NASA NTRS1986

Investigation of nickel hydrogen battery technology for the RADARSAT spacecraft

The low Earth orbit (LEO) operations of the RADARSAT spacecraft require high performance batteries to provide energy to the payload and platform during eclipse period. Nickel Hydrogen cells are currently competing with the more traditional Nickel Cadmium cells for high performance spacecraft applications at geostationary Earth orbit (GEO) and Leo. Nickel Hydrogen cells appear better suited for high power applications where high currents and high Depths of Discharge are required. Although a number of GEO missions have flown with Nickel Hydrogen batteries, it is not readily apparent that the LEO version of the Nickel Hydrogen cell is able to withstand the extended cycle lifetime (5 years) of the RADARSAT mission. The problems associated with Nickel Hydrogen cells are discussed in the contex of RADARSAT mission and a test program designed to characterize cell performance is presented.

Mccoy, D. A.↗
NASA NTRS1975

Life sciences laboratory breadboard simulations for shuttle

Breadboard simulations of life sciences laboratory concepts for conducting bioresearch in space were undertaken as part of the concept verification testing program. Breadboard simulations were conducted to test concepts of and scope problems associated with bioresearch support equipment and facility requirements and their operational integration for conducting manned research in earth orbital missions. It emphasized requirements, functions, and procedures for candidate research on crew members (simulated) and subhuman primates and on typical radioisotope studies in rats, a rooster, and plants.

Taketa, S. T.↗
NASA NTRS1998

COOP 3D ARPA Experiment 109 National Center for Atmospheric Research

Coupled atmospheric and hydrodynamic forecast models were executed on the supercomputing resources of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado and the Ohio Supercomputing Center (OSC)in Columbus, Ohio. respectively. The interoperation of the forecast models on these geographically diverse, high performance Cray platforms required the transfer of large three dimensional data sets at very high information rates. High capacity, terrestrial fiber optic transmission system technologies were integrated with those of an experimental high speed communications satellite in Geosynchronous Earth Orbit (GEO) to test the integration of the two systems. Operation over a spacecraft in GEO orbit required modification of the standard configuration of legacy data communications protocols to facilitate their ability to perform efficiently in the changing environment characteristic of a hybrid network. The success of this performance tuning enabled the use of such an architecture to facilitate high data rate, fiber optic quality data communications between high performance systems not accessible to standard terrestrial fiber transmission systems. Thus obviating the performance degradation often found in contemporary earth/satellite hybrids.

Source record↗
NASA NTRS1988

Planetary operations for the Pioneer Venus Orbiter mission

The Pioneer Venus Orbiter was inserted into Venus orbit on December 4, 1974 and is expected to operate until 1992. This paper discusses the scientific objectives of the Pioneer Venus Orbiter Project components, i.e., the Orbiter spacecraft, the atmosphere entry Probes, and the probe Bus, together with the design and operation characteristics of the Orbiter. Consideration is also given to the science instruments of the Orbiter, to their requirements with respect to pointing, orientation, and timing, and to the ground operations system. The Probes, the Bus, and the Orbiter were selected to study Venus in complementary ways: the Probes by sounding through most of the atmosphere at four locations, the probe Bus by sounding through the upper atmosphere during entry, and the Orbiter by in situ planet-wide observations of the ionosphere and the extreme upper atmosphere, and by examining the surface and interior remotely. In addition, the Orbiter also observes the interactions of Venus with the solar environment.

Jackson, Robert W.↗
NASA NTRS2008

Orbit Control Operations for the Cassini-Huygens Mission

The Cassini-Huygens spacecraft was launched in 1997 as an international and collaborative mission to study Saturn and its many moons. After a seven-year cruise, Cassini began orbiting Saturn for a four- year tour. This tour consists of 157 planned maneuvers, and their back-up locations, designed to target 52 encounters, mostly of Saturn's largest moon Titan. One of the mission's first activities was to release the Huygens probe to Titan in December 2004. Currently in its last year of the prime mission, Cassini-Huygens continues to obtain valuable data on Saturn, Titan, and Saturn's other satellites. Return of this information is in large part due to a healthy spacecraft and successful navigation. A two-year extended mission, beginning July 2008, will offer the opportunity to continue science activities. With a demanding navigation schedule that compares with the prime tour, the Cassini Navigation team relies on operations procedures developed during the prime mission to carry-out the extended mission objectives. Current processes for orbit control operations evolved from the primary navigational requirement of staying close to predetermined targeting conditions according to Cassini science sequence planning. The reference trajectory is comprised of flyby conditions to be accomplished at minimal propellant cost. Control of the planned reference trajectory orbit, and any trajectory updates, is achieved with the execution of Orbit Trim Maneuvers (OTMs). The procedures for designing, processing, and analyzing OTMs during Cassini operations is presented. First, a brief overview of the Cassini-Huygens Mission is given, followed by a general description of navigation. Orbit control and maneuver execution methods are defined, along with an outline of the orbit control staffing and operations philosophy. Finally, an example schedule of orbit control operations is shown.

navigation↗
NASA NTRS1973

Mariner 9 Solar Array Design, Manufacture, and Performance

The mission of Mariner 9, the first spacecraft to orbit another planet, was to make scientific observations of the surface of Mars. Throughout this unique mission, the Mariner 9 solar array successfully supported the power requirements of the spacecraft without experiencing anomalies. Basically, the design of the solar array was similar to those of Mariners 6 and 7; however, Mariner 9 had the additional flight operational requirement to perform in a Mars orbit environment mode. The array special tests provided information on the current-voltage characteristics and array space degradation. Tests indicated that total solar array current degradation was 3.5 percent, which could probably be attributed to the gradual degradation of the cover glass and/or the RTV 602 adhesive employed to cement the cover glass to the solar cell.

Sequeira, E. A.↗
NASA NTRS1986

Conceptual planning for Space Station life sciences human research project

The Life Sciences Research Facility dedicated laboratory is currently undergoing system definition within the NASA Space Station program. Attention is presently given to the Humam Research Project portion of the Facility, in view of representative experimentation requirement scenarios and with the intention of accommodating the Facility within the Initial Operational Capability configuration of the Space Station. Such basic engineering questions as orbital and ground logistics operations and hardware maintenance/servicing requirements are addressed. Biospherics, calcium homeostasis, endocrinology, exercise physiology, hematology, immunology, muscle physiology, neurosciences, radiation effects, and reproduction and development, are among the fields of inquiry encompassed by the Facility.

Primeaux, Gary R.↗
NASA NTRSDate not supplied

Compatibility Between Exploration EVA System and Exploration Spacecraft

Over the life of the Extravehicular Mobility Unit (EMU), numerous products detailing “how to build Extravehicular Activity (EVA) System hardware”, “how to interface with EVA System hardware” and “how to design hardware EVA will access and utilize” were generated to provide interoperability between a suited crewmember and the specified vehicle’s EVA task. Since the inception of these products, some have continued to receive updates due to the necessity of an on-going program while others remained unchanged for years and have led to discrepancies between the current accepted values and those considered outdated. For EVA-suited crewmember tasks beyond Low Earth Orbit (LEO), new vehicles need a single consolidated location for the best practices and lessons learned from the EVA Community. This paper outlines what common EVA compatibility design requirements are expected of an Exploration spacecraft that has interactions between the vehicle and an EVA suited crewmember for and an approach for standardizing EVA compatibility across various vehicles at various destinations. The approach of standardization allows for flexibility by tailoring the applicability to meet the EVA tasks required for that vehicle’s operation beyond Low Earth Orbit. This paper will also describe the broad difference between microgravity and partial gravity EVA compatibility and how those requirements were identified and will be informed.

Compatibility↗
NASA NTRS1989

Operations considerations in Space Station Freedom assembly

The importance of planning the on-orbit operations inherent in the Space Station Freedom assembly sequence is discussed. Any solution to the assembly puzzle requires the simultaneous satisfaction of many diverse constraints, including: on-orbit assembly operations, NSTS (National Space Transportation System) payload bay constraints, NSTS performance capabilities, and provision of the requisite functionality for each on-orbit configuration. Because operations are in the critical path SSFP (Space Station Freedom Program) has chosen to carefully assess assembly operations as each launch manifest is developed and evaluated.

Doering, Stephen C.↗
DOE OSTI2023

Spin dynamics in quantum dots on liquid helium

Liquid He-4 is free from magnetic defects, making it an ideal substrate for electrons with long-lived spin states. Such states can serve as qubit states. Here, in this study, we consider the spin states of electrons electrostatically localized in quantum dots on a helium surface. Efficient gate operations in this system require spin-orbit coupling. It can be created by a nonuniform magnetic field from a current-carrying wire, can be turned on and off, and allows one to obtain large electrodipole moment and comparatively fast coupling of spins in neighboring dots. Of central importance is to understand spin decay due to the spin-orbit coupling. We establish the leading mechanism of such decay and show that the decay is sufficiently slow to enable high-fidelity single- and two-qubit gate operations.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗