Engineering topics

Kroll, K.

Publications and source records attributed to Kroll, K..

5 records

NASA NTRS1986

US gravity utilization of tethers activity

The feasibility, requirements, and limitations of fluid transfer on a tethered system is evaluated. The study is conducted to simplify fluid transfer and to improve safety. The effects of gravity on these factors is also noted. Tether orbital refueling is used to settle fluid and to overcome the surface tension forces that are in space with the gravity level. It also allows a separation, when on the space station, from contamination and also from explosion hazards. Once the cryogenic propellant is settled the most important thing is the fluid slosh. Future plans of a gravity laboratory and a demonstration of gravity utilization using a TSS type of deployer are considered.

Kroll, K.↗

NASA NTRS1986

Orbital-Transfer Vehicle With Aerodynamic Braking

Vehicle includes airbrake for deceleration into lower orbit. Report describes vehicle for carrying payloads between low and high orbits around Earth. Vehicle uses thin, upper atmosphere for braking when returning to low orbit. Since less propellant needed than required for full retrorocket braking, vehicle carries larger payload and therefore reduces cost of space transportation.

Scott, C. D.↗

NASA NTRS1985

Report of the Artificial Gravity Panel

Tethers can be embodied into NASA's future space station development both as an experimental facility and as a technology for systems enhancement. Early action should be taken to ensure that the basic tether system be baselined into the initial space station architecture and that further concept studies be arranged to embody this basic capability. Space station tethered satellite operations would be continuous, subject to need and occasional association with local spacecraft operations in the proximity of the space station. The use of the tether principles would be further explored for attitude control and/or attitude stabilization damping, and proximity operations. For new tether uses, action should be taken to look at the tether for holding storage uses, proximity operations, and for extension of the capabilities of attached payloads systems. These applications should emphasize dynamic off-vertical tethers, rapid deployment, active-steered tethers, tether-boom combinations, and other concepts.

Butler, G.↗

NASA NTRS1984

Propellant transfer: Tethered depot

Spacebasing of orbital transfer vehicles at a space station requires a depot that safely and efficiently stores and transfers the resupply propellants. In order to transfer propellants, a method effectively acquire only liquid and vent only gas must exist. A method that produces a low gravity to settle propellants would bypass these weaknesses, while allowing ground-like operations. This low gravity can be passively produced using gravity gradient techniques. A satellite with a large length to diameter ratio, such as a depot attached to a space station with a tether, stabilizes along on Earth radial because of an outward acceleration proportional to the distance from the satellite's center of gravity. Analysis indicates that liquid can be setteled with relatively short tether lengths. The feasibility, design requirements, and operational limitations of a tethered refueling depot were investigated with special emphasis on slosh control.

Kroll, K.↗

NASA NTRS1979

Flow measurements in a turbine scroll

The paper presents a study conducted to determine experimentally the flow behavior in the combined scroll nozzle assembly of a radial inflow turbine. It is shown that hot film anemometry was used to measure the flow velocity in the scroll.

Tabakoff, W.↗