Engineering topics

Carroll, Joseph A.

Publications and source records attributed to Carroll, Joseph A..

11 records

NASA NTRS2007

Multilayer Impregnated Fibrous Thermal Insulation Tiles

The term "secondary polymer layered impregnated tile" ("SPLIT") denotes a type of ablative composite-material thermal- insulation tiles having engineered, spatially non-uniform compositions. The term "secondary" refers to the fact that each tile contains at least two polymer layers wherein endothermic reactions absorb considerable amounts of heat, thereby helping to prevent overheating of an underlying structure. These tiles were invented to afford lighter-weight alternatives to the reusable thermal-insulation materials heretofore variously used or considered for use in protecting the space shuttles and other spacecraft from intense atmospheric-entry heating.

Tran, Huy K.↗

NASA NTRS2005

Secondary polymer layered impregnated tile

A low density organic polymer impregnated preformed fibrous ceramic article includes a plurality of layers. A front layer includes ceramic fibers or carbon fibers or combinations of ceramic fibers and carbon fibers, and is impregnated with an effective amount of at least one organic polymer. A middle layer includes polymer impregnated ceramic fibers. A back layer includes ceramic fibers or carbon fibers or combinations of ceramic fibers and carbon fibers, and is impregnated with an effective amount of at least one low temperature pyrolyzing organic polymer capable of decomposing without depositing residues.

Tran, Huy K.↗

NASA NTRS2004

Optical Diagnostic System for Solar Sails: Phase 1 Final Report

NASA's In-Space Propulsion program recently selected AEC-ABLE Engineering and L'Garde, Inc. to develop scale-model solar sail hardware and demonstrate its functionality on the ground. Both are square sail designs with lightweight diagonal booms (<100 g/m) and ultra-thin membranes (<10 g/sq m). To support this technology, the authors are developing an integrated diagnostics instrumentation package for monitoring solar sail structures such as these in a near-term flight experiment. We refer to this activity as the "Optical Diagnostic System (ODS) for Solar Sails" project. The approach uses lightweight optics and photogrammetric techniques to measure solar sail membrane and boom shape and dynamics, thermography to map temperature, and non-optical sensors including MEMS accelerometers and load cells. The diagnostics package must measure key structural characteristics including deployment dynamics, sail support tension, boom and sail deflection, boom and sail natural frequencies, sail temperature, and sail integrity. This report summarizes work in the initial 6-month Phase I period (conceptual design phase) and complements the final presentation given in Huntsville, AL on January 14, 2004.

Pappa, Richard S.↗

NASA NTRS1998

A Station Tethered Express Payload System (STEPS)

Most capsules designed to return payloads from earth orbit use rockets for deorbit. They have modest payload mass & volume fractions. Active attitude control raises costs, and the deorbit rocket imposes risks which increase development and operational costs. This note describes an alternative concept now being developed under NASA funding. It uses a tether to both deorbit and orient the capsule. This allows simultaneous reduction of capsule complexity, cost, loads, hazards, and reentry errors. The flight of SEDS-1 in 1993 proved out the basic concepts. A 20 km tether slung a 26 kg payload back to earth from a 74O x 19O km orbit, accurately enough for a pre-positioned observer to videotape the reentry. As air drag built up just before reentry, the tether was blown back and became a kite-tail, with tension increasing as predicted before flight. The tether was still attached at approx. 110 km, when telemetry was lost.

Carroll, Joseph A.↗

NASA NTRS1993

Tether Deployer And Brake

Design concept promises speed, control, and reliability. Scheme for deploying tether provides for fast, free, and snagless payout and fast, dependable braking. Developed for small, expendable tethers in outer space, scheme also useful in laying transoceanic cables, deploying guidance wires to torpedoes and missiles, paying out rescue lines from ship to ship via rockets, deploying antenna wires, releasing communication and power cables to sonobuoys and expendable bathythermographs, and in reeling out lines from fishing rods.

Carroll, Joseph A.↗

NASA NTRS1992

Tethers

A tether of sufficient strength, capable of being lengthened or shortened and having appropriate apparatuses for capturing and releasing bodies at its ends, may be useful in propulsion applications. For example, a tether could allow rendezvous between spacecraft in substantially different orbits without using propellant. A tether could also allow co-orbiting spacecraft to exchange momentum and separate. Thus, a reentering spacecraft (such as the Shuttle) could give its momentum to one remaining on orbit (such as the space station). Similarly, a tether facility could gain momentum from a high I(sub sp)/low thrust mechanism (which could be an electrodynamics tether) and transfer than momentum by means of a tether to payloads headed for many different orbits. Such a facility would, in effect, combine high I(sub sp) with high thrust, although only briefly. An electrodynamic tether could propel a satellite from its launch inclination to a higher or lower inclination. Tethers could also allow samples to be taken from bodies such as the Moon. Three types of tether operations are illustrated. The following topics are discussed: (1) tether characteristics; (2) tether propulsion methods--basics, via momentum transfer, and electrodynamic tether propulsion; and (3) their use in planetary exploration.

Cutler, Andrew Hall↗

NASA NTRS1990

In-orbit experimentation with the Small Expendable-Tether Deployment System

The Small Expendable-Tether Deployment System (SEDS) is a light-weight deployer capable of deploying instrumented packages and other tethered payloads up to a distance of 20 km. The system is simple and inexpensive because it does not retrieve the tethered payloads. The deployer is attached to the second stage of a Delta II which acts as a stabilized platform for the deployment of tethered payloads. SEDS is particularly suitable for complementing the Tethered Satellite missions by providing a flexible system for experimenting with the tether-in-space technology. SEDS can also provide a convenient way for testing instruments and/or procedures which require the use of long tethers.

Lorenzini, Enrico C.↗

NASA NTRS1990

SEDS experiment design definition

The Small Expendable-tether Deployment System (SEDS) was developed to design, build, integrate, fly, and safely deploy and release an expendable tether. A suitable concept for an on-orbit test of SEDS was developed. The following tasks were performed: (1) Define experiment objectives and requirements; (2) Define experiment concepts to reach those objectives; (3) Support NASA in experiment concept selection and definition; (4) Perform analyses and tests of SEDS hardware; (5) Refine the selected SEDS experiment concept; and (6) Support interactive SEDS system definition process. Results and conclusions are given.

Carroll, Joseph A.↗

NASA NTRS1989

Small Expendable-tether Deployer System (SEDS) development status

Plans for proposed flight of the Small Expendable-tether Deployer System (SEDS) on a Delta II launch vehicle are discussed. The SEDS tether concept and mission requirements are outlined. Results are presented from calculations of the tether dynamics and computer modeling to determine tether behavior. The tether's thermal characteristics, electronics system, material, data collection procedure, payload, and orbital trace are described.

Harrison, James K.↗

NASA NTRS1988

The Small Expendable Deployment System (SEDS)

A Small Expendable-tether Deployment System (SEDS) has been developed for use with the Space Shuttle, expendable launch vehicles, and the Space Station. The basic SEDS concept and work done on it to date are reviewed. Control issues, the advantages and disadvantages of this deployment concept, some generic tether safety issues, simulation programs, and testing are described. Potential SEDS applications are reviewed.

Carroll, Joseph A.↗

NASA NTRS1988

Some tether applications with small launch vehicles

This paper describes four potentially useful tether applications that are best suited to or even limited to small launch vehicles and their payloads. The first application uses a Small Expendable-tether Deployment System (SEDS) to deploy a 20-40 km tether which transfers momentum from the spent final stage to its payload. This de-orbits the stage and boosts the payload. The other concepts are endo-atmospheric applications specific to various kinds of boosters. In one, a large helicopter gently recovers a reusable booster while it is descending by parachute. Another improves the performance of a small single-stage-to-orbit launch vehicle, by lifting it by helicopter to an altitude of about 3 kilometers before ignition. The last tows an air-breathing launch vehicle to high speed behind a supersonic aircraft, to eliminate any need for low-speed propulsion on the launch vehicle.

Carroll, Joseph A.↗