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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 451 records · Page 25

Optimal aeroassisted transfer between coplanar elliptical orbits

An attempt is made to solve the problem of orbital transfer between coplanar elliptical orbits. Pure propulsive transfer is analyzed with the restriction of two impulses for the transfer. The optimal switching conditions are reviewed, and it is shown that the solution is obtained by solving a set of three nonlinear equations for three unknowns. A semianalytical solution is obtained to the problem of planar rotation of an orbit for the pure propulsive maneuver, and it is shown that, for high eccentricity and rotation angle, aeroassisted transfer is a fuel-saving maneuver. It is demonstrated that complete circularization of the intermediate orbit is not necessary in the optimal aeroassisted transfer. An analytical proof is presented, giving an explicit condition for noncircularization. A complete numerical solution is presented for a case of optimal aeroassisted transfer from a low-energy orbit to a high-energy orbit.

Vinh, N. X.↗

Satellite Power System (SPS) concept definition study (exhibit C)

The major outputs of the study are the constructability studies which resulted in the definition of the concepts for satellite, rectenna, and satellite construction base construction. Transportation analyses resulted in definition of heavy-lift launch vehicle, electric orbit transfer vehicle, personnel orbit transfer vehicle, and intra-orbit transfer vehicle as well as overall operations related to transportation systems. The experiment/verification program definition resulted in the definition of elements for the Ground-Based Experimental Research and Key Technology plans. These studies also resulted in conceptual approaches for early space technology verification. The cost analysis defined the overall program and cost data for all program elements and phases.

Haley, G. M.↗

Analysis of orbital heat transfer

Graphical representation of orbital heat balance in form of polar diagrams is obtained from integral expressions of orbital heat transfer whereby quantities of heat are represented as areas swept by ""thermal radii.''

Buna, T.↗

System Requirements and Operations Panel Workshop summary

The low Earth orbit (LEO) versus the geosynchronous Earth orbit (GEO) deployment systems were discussed. The following items are emphasized: (1) large area systems, such as deployment, altitude, orbit transfer, and on orbit operation; (2) propulsion oriented issues such as the orbit transfer vehicle and the auxiliary propulsion systems; (3) programmatic issues. The LEO versus GEO deployment is a significant driver on propulsion requirements for an orbit transfer vehicle. It is suggested that early systems will be deployed at LEO. The Shuttle remote manipulator system (RMS) will not be involved in early demonstration activities. It is concluded that an integrated large space system/propulsion approach is essential and that propulsion development requirements need to be established.

Schwarzberg, F. R.↗

Gateway: An earth orbiting transportation node

University of Texas Mission Design (UTMD) has outlined the components that a space based transportation facility must include in order to support the first decade of Lunar base buildup. After studying anticipated traffic flow to and from the hub, and taking into account crew manhour considerations, propellant storage, orbital transfer vehicle maintenance requirements, and orbital mechanics, UTMD arrived at a design for the facility. The amount of activity directly related to supporting Lunar base traffic is too high to allow the transportation hub to be part of the NASA Space Station. Instead, a separate structure should be constructed and dedicated to handling all transportation-related duties. UTMD found that the structure (named Gateway) would need a permanent crew of four to perform maintenance tasks on the orbital transfer and orbital maneuvering vehicles and to transfer payload from launch vehicles to the orbital transfer vehicles. In addition, quarters for 4 more persons should be allocated for temporary accommodation of Lunar base crew passing through Gateway. UTMD was careful to recommend an expendable structure that can adapt to meet the growing needs of the American space program.

Source record↗

Conceptual design of the subscale orbital fluid transfer experiment (SOFTE)

The Subscale Orbital Fluid Transfer Experiment is a planned space experiment with the objective of obtaining video and numerical data on fluid dynamics and thermal physics pertinent to on-orbit liquid acquisition and tank filling operations, particularly with cryogens. These data have significant application to space-based transportation systems, Space Station Freedom, and space defense systems. This paper presents the rationale for the experiment and a description of its design. The experiment will mount in two Get Away Special canisters that are connected to each other by an electrical umbilical. It involves transferring Freon 113 between two transparent plexiglass tanks. Axial and tangential no-vent fills will be done over a range of flow rates. The apparatus includes a screened-channel liquid acquisition device with plexiglass channels for examining vapor breakthrough and channel refill processes. Video cameras will monitor the transfer operations.

Jones, O. S.↗

Rideshare Strategies for Small Mars Missions

Frequent low-cost access to Mars can be enabled by taking advantage of the increasing number of rideshare-compatible launches. The cost to manifest a small spacecraft as a secondary can be a small fraction of the cost of a dedicated launch. However, not all rideshare opportunities are equally suitable for a mission to Mars. Much depends on the delivery orbit, mass available, launch date, and propulsion strategy. This paper outlines various mission starting points along with corresponding methods to deliver payloads to Mars from each option. These starting points include low-Earth Orbit (LEO), geosynchronous transfer orbit (GTO), Lunar transfer orbit (LTO), and Earth escape.

Stamenkovic, Vlada↗

Tethered propellant resupply technique for space stations

One of the primary functions of the space station is related to the propellant resupply of orbital transfer vehicles, orbital maneuvering vehicles, and satellites. Difficulties arise in the case of an acquisition of cryogenic propellants by means of a use of zero-gravity techniques. The use of the 'tethered propellant resupply technique' is, therefore, considered. A study is being conducted to determine the feasibility, design requirements, and operational limitations of this technique. Attention is given to aspects of gravity feed, transfer method selection, requirements related to the orbital transfer vehicle, hazard clearance, attitude control, depot operations, end mass velocity, the microgravity laboratory, and concept evaluation activities.

Kroll, K. R.↗

Crew transfer in orbiting spacecraft

Problems of maneuverability, locomotion, and propulsion in zero gravity, and protection and support during astronaut transfer in orbiting spacecraft

ORBITAL TRANSFER↗

Thermal analogies to Kepler's laws and their application to orbital heat transfer calculations

Integral expressions of radiant transfer in Keplerian orbits are developed in which quantities of heat are represented by areas swept over by thermal radii (presently introduced). The integrals are shown to be analogous in form to the solutions provided by Kepler's laws in orbital mechanics, when the radiation field is concentric with the gravitational field and possesses spherical symmetry. The more general case involving aspherical radiation fields and multiple heat sources is treated by graphical integration, using polar diagrams. Applications pertaining to the solar system and to the thermal balance of a conceptual Venus Radar Mapper Spacecraft are discussed.

Buna, T.↗

The NASA/USAF arcjet research and technology program

Direct current arcjets have the potential to provide specific impulses greater than 500 sec with storable propellants, and greater than 1000 sec with hydrogen. This level of performance can provide significant benefits for such applications as orbit transfer, station keeping, orbit change, and maneuvering. The simplicity of the arcjet system and its elements of commonality with state-of-the-art resistojet systems offer a relatively low risk transition to these enhanced levels of performance for low power (0.5 to 1.5 kW) station keeping applications. Arcjets at power levels of 10 to 30 kW are potentially applicable to orbit transfer missions. Furthermore, with the anticipated development of space nuclear power systems, arcjets at greater than 100 kW may become attractive. This paper describes the ongoing NASA/USAF program and describes major recent accomplishments.

Stone, James R.↗

The NASA/USAF arcjet research and technology program

Direct current arcjets have the potential to provide specific impulses greater than 500 sec with storable propellants, and greater than 1000 sec with hydrogen. This level of performance can provide significant benefits for such applications as orbit transfer, station keeping, orbit change, and maneuvering. The simplicity of the arcjet system and its elements of commonality with state-of-the-art resistojet systems offer a relatively low risk transition to these enhanced levels of performance for low power (0.5 to 1.5 kW) station keeping applications. Arcjets at power levels of 10 to 30 kW are potentially applicable to orbit transfer missions. Furthermore, with the anticipated development of space nuclear power systems, arcjets at greater than 100 kW may become attractive. This paper describes the ongoing NASA/USAF program and describes major recent accomplishments.

Stone, James R.↗

Moon Base Transportation - Deliveries to the Lunar Surface

Development of the Moon Base will enable a home away from home for astronauts who will live and work at humanity’s first lunar outpost. In this effort, NASA’s Moon Transportation Office is responsible for enabling the transformational missions required to deliver habitats, supplies, science payloads, and all other elements needed to cultivate a permanent presence on the Lunar Surface. The Mission Concept (MC) is characterized through evaluation of an end-to-end architecture that can successfully deliver a generalized heavy large-volume payload, in excess of 4000 kg, to a precision landing and touchdown on the lunar surface. The mission architecture utilizes a single launch configuration of a Lunar Lander (LL) with a unique propellant system. The LL has an integral orbital transfer capability and features jettisonable elements. The design circumvents the need for prop transfer on orbit and multiple launch configurations. The launch vehicle (LV) for this work will assume the capability to deliver a payload in excess of 40,000 kg to orbit, affording multiple LV solutions. Considerations for the LL and payload deployment from the fairing are assumed to be handled through compliance with a launch providers’ Interface Requirements Document (IRD). The MC will span from launch at Kennedy Space Center (KSC) to terminal descent and touchdown on the lunar surface, requiring a total ΔV on the order of 6 km/s beyond what is required to get the vehicle stack to a 200 km circular Low Earth Orbit (LEO). Major mission phases include: launch and launch vehicle separation, transfer operations, pre-landing navigation, and lunar descent and touchdown. A Concept of Operations (ConOps) is used as the primary design driver for defining architecture of the vehicles necessary to achieve final payload delivery. Numerous ground rules and assumptions will be provided for each phase of the mission. Concept designs for the LL is presented. An emphasis of the design maximizes a feasible path for maturation, manufacturing, and operation. A self-imposed practical consideration for this effort is the incorporation of legacy designed hardware to minimize expensive, time-intensive, and high-risk hardware development cycles. The propulsion system of the LL adopts a conventional storable bipropellant configuration of monomethyl hydrazine (MMH) and mixed oxides of nitrogen (MON3). This effort will showcase a unique propellant delivery system to minimize the reliance on propellant management devices (PMDs) during descent. Numerous key constraints have been considered, across the multiple segments of the mission. These include the unique aspects of center of gravity (CG) management, thruster plume effects including self-impingement, propulsion system hardware limitations, navigation during multiple mission phases, and landing gear geometry for uneven terrain. These constraints shape the trades necessary for precision landing of heavy cargo and ensure compatibility with broader Moon Base Transportation concepts. The resulting insights inform future transportation strategies for the Moon and beyond; directly contributing to the development of cargo‑delivery standards that will support the long‑term buildup of a sustainable, continuously inhabited Moon Base.

Lunar Habitat↗