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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Dynamic Charging Rendezvous and Motion Planning for a Multi-AGV Team Including a Mobile Charging Host

Teams of automated battery-powered electric vehicles have the potential to execute complex mission tasks in off-road environments for agriculture, military, and other applications. Limited onboard energy reserves hinder their adoption in large-scale resource-constrained environments, where recharging is a necessity. It may be infeasible to install a network of static charging stations in off-road environments. For this reason, dedicated mobile host vehicles with charging capabilities are proposed as a means to increase range and capabilities of the multivehicle team. Here, in this study, we consider an ad hoc planning framework, where results from a high-confidence trajectory planner are leveraged to plan charging rendezvous between a host and other worker vehicles in a receding horizon fashion to provide high confidence that energy reserves will not be prematurely exhausted. The core problem is posed so as to minimize the impact of recharging on the mission in terms of task delays, overall energy utilization, and costs of fast charging. Through extensive Monte Carlo simulations of an off-road mission, we show a decrease in task delays without substantial increases in energy needs by updating the charging rendezvous plan during the mission. However, if updates are made too often, model mismatch may cause unnecessary cycling and mission failure.

Energy constraints↗
NASA NTRS1967

Onboard operations for rendezvous

An overall plan for onboard rendezvous operations for the Gemini missions was developed in parallel with the mission plan. The purpose of this plan was to make optimum use of crew time in orbit to maximize the probability of a successful rendezvous. The evolution of the plan began with a preliminary time line of events based upon the known guidance-equipment requirements and upon the estimated crew timing. A preliminary set of flight charts was developed to aid the crew with primary and backup procedures and to establish a backup guidance capability. These charts, which consisted of a few simple graphs and tabulation sheets, enabled the crew to calculate accurate solutions for the terminal maneuvers even with an inoperative guidance-equipment component. As such, the charts significantly contributed to the probability of mission success. Following the development of the charts, an engineering evaluation was conducted on a realistic man-in-the-loop simulation. During this evaluation, the procedures and charts were subjected to the expected equipment errors and trajectory dispersions, and revisions were made as necessary to improve effectiveness. The resulting plan was presented to the flight crew; the charts were evaluated during a period of training on the simulator. The crew spent several weeks training on both the primary procedures and on the various failure modes.

structural integrity↗
NASA NTRS1970

Polynomial filter estimation of range and range rate for terminal rendezvous

A study was made of a polynomial filter for computing range rate information from CSM VHF range data. The filter's performance during the terminal phase of the rendezvous is discussed. Two modifications of the filter were also made and tested. A manual terminal rendezvous was simulated and desired accuracies were achieved for vehicles on an intercept trajectory, except for short periods following each braking maneuver when the estimated range rate was initially in error by the magnitude of the burn.

Philips, R.↗
NASA NTRS1972

Shuttle on-orbit rendezvous targeting: Circular orbits

The strategy and logic used in a space shuttle on-orbit rendezvous targeting program are described. The program generates ascent targeting conditions for boost to insertion into an intermediate parking orbit, and generates on-orbit targeting and timeline bases for each maneuver to effect rendezvous with a space station. Time of launch is determined so as to eliminate any plane change, and all work was performed for a near-circular space station orbit.

Bentley, E. L.↗
NASA NTRS1972

Atmospheric rendezvous feasibility study

A study was carried out to determine the feasibility of using atmospheric rendezvous to increase the efficiency of space transportation and to determine the most effective implementation. It is concluded that atmospheric rendezvous is feasible and can be utilized in a space transportation system to reduce size of the orbiter vehicle, provide a powered landing with go-around capability for every mission, and achieve lateral range performance that exceeds requirements. A significantly lighter booster and reduced launch fuel requirements are additional benefits that can be realized with a system that includes a large subsonic airplane for recovery of the orbiter. Additional reduction in booster size is possible if the airplane is designed for recovery of the booster by towing. An airplane about the size of the C-5A is required.

Schaezler, A. D.↗
NASA NTRS1972

Encounter trajectory design for SEP rendezvous with low mass celestial bodies.

This paper shows the considerations which precede and affect encounter trajectory design and the impact of this design on propulsion system performance requirements and interplanetary trajectory design. Representative missions selected to illustrate the problems and characteristics of encounter trajectory design are a Mercury Orbiter, Eros Rendezvous, Encke Rendezvous, and Ceres Orbiter. The paper shows that for SEP missions, particularly for low mass celestial bodies, the encounter trajectory may be freely specified to a large extent to satisfy mission goals rather than being dictated by a rigid interplanetary trajectory design.

Driver, J. M.↗
NASA NTRS1971

Comet rendezvous mission study

Four periodic comets with perihelia between 1980 and 1986 (Encke, d'Arrest, Kipff, and Halley) are used as candidates for the comet rendezvous mission study. All these comet apparitions are especially favorable for rendezvous missions, because of early earth-based comet recovery, good opportunities to view their activity from earth, and reasonable launch vehicle and trajectory requirements for nominal payloads.

Friedlander, A. L.↗
NASA NTRS1974

A feasibility study of unmanned rendezvous and docking in Mars orbit: Midterm review

The ascent, rendezvous, docking and sample transfer operations in a potential MSSR mission that uses the Mars orbital rendezvous mode are considered. In order that the design choices made for these operations remain compatible with the rest of the mission, the impact on the Earth launch, Mars landing and orbiting and Earth return phase are also being assessed. The selection and description of a preliminary baseline concept are presented.

Source record↗
NASA NTRS1973

Solar electric propulsion for terminal flight to rendezvous with comets and asteroids

A guidance algorithm that provides precise rendezvous in the deterministic case while requiring only relative state information is developed. A navigation scheme employing only onboard relative measurements is built around a Kalman filter set in measurement coordinates. The overall guidance and navigation procedure is evaluated in the face of measurement errors by a detailed numerical simulation. Results indicate that onboard guidance and navigation for the terminal phase of rendezvous is possible with reasonable limits on measurement errors.

Bennett, A.↗
NASA NTRS1975

Tracking techniques for space shuttle rendezvous

The space shuttle rendezvous radar has a requirement to track cooperative and non-cooperative targets. For this reason the Lunar Module (LM) Rendezvous Radar was modified to incorporate the capability of tracking a non-cooperative target. The modifications are discussed. All modifications except those relating to frequency diversity were completed, and system tests were performed to confirm proper performance in the non-cooperative mode. Frequency diversity was added to the radar and to the special test equipment, and then system tests were performed. This last set of tests included re-running the tests of the non-cooperative mode without frequency diversity, followed by tests with frequency diversity and tests of operation in the original cooperative mode.

Source record↗
NASA NTRS1974

Laser space rendezvous and docking tradeoff

A spaceborne laser radar (LADAR) was configured to meet the requirements for rendezvous and docking with a cooperative object in synchronous orbit. The LADAR, configurated using existing pulsed CO2 laser technology and a 1980 system technology baseline, is well suited for the envisioned space tug missions. The performance of a family of candidate LADARS was analyzed. Tradeoff studies as a function of size, weight, and power consumption were carried out for maximum ranges of 50, 100, 200, and 300 nautical miles. The investigation supports the original contention that a rendezvous and docking LADAR can be constructed to offer a cost effective and reliable solution to the envisioned space missions. In fact, the CO2 ladar system offers distinct advantages over other candidate systems.

Adelman, S.↗
NASA NTRS1977

Laser space rendezvous and docking system study continuation

Investigations were made of a configuration for a spaceborne laser radar (ladar) to meet the requirements for rendezvous and docking with a cooperative object in synchronous orbit. An analysis was completed of laser phase locking techniques, while experimental verification was made of pulse repetition frequency and resonant scanning control loops. Data measurements on a satellite mock-up were also made. The investigation supports the original contention that a rendezvous and docking ladar can be configured to offer a cost effective and reliable solution to envisioned space missions.

Adelman, S.↗
NASA NTRS1978

SEP ENCKE-87 and Halley rendezvous studies and improved S/C model implementation in HILTOP

Studies were conducted to determine the performance requirements for projected state-of-the-art SEP spacecrafts boosted by the Shuttle/IUS to perform a rendezvous with the comet Halley and a rendezvous with the comet Encke during its 1977 apparition. The spacecraft model of the standard HILTOP computer program was assumed. Numerical and graphical results summarizing the studies are presented.

Horsewood, J. L.↗
NASA NTRS1978

Halley comet rendezvous with a SEPS vehicle

An analysis of the performance of a Solar Electric Propulsion System (SEPS) vehicle rendezvousing with Halley's comet just prior to its Frebruary 1986 perihelion is described. A calculus of variations mathematical formulation is used to maximize Halley arrival mass while giving effect to the influence of solar array size, launch date, arrival date, and insertion hyperbolic excess velocity. Numerical sensitivity relief, thrust system modeling, trajectory characteristics and ion engine operating conditions are discussed and illustrated. Results indicate a rendezvous is feasible with a minimal advance in solar cell and ion engine technology.

Burrows, R. R.↗
NASA NTRS1977

A comparison of solar sail and ion drive trajectories for a Halley's comet rendezvous mission

According to the propulsion concept of solar sail spacecraft the thrust force is produced by the specular reflection of sunlight from a large, essentially flat, reflecting surface. The magnitude of this force is approximately 9 newtons for a perfectly reflecting sail with an area of 1 square kilometer oriented normal to the sunline at a distance of one astronomical unit from the sun. There exists a restriction in the types of orbit transfer trajectories which can be considered with this propulsion system. In the case of the second propulsion system being considered for the Halley's comet rendezvous mission, thrust is produced by the acceleration of ionized mercury atoms by an electric field. Power to the ion thrusters is supplied by lightweight solar arrays which can provide up to 100 kW of electrical power at a distance of 1 AU from the sun. Because of differing thrust constraints for the two propulsion systems, trajectories for a Halley's comet rendezvous mission are significantly different for the Ion Drive and Solar Sail spacecraft. Details concerning the trajectory characteristics are shown with the aid of a number of graphs.

Sauer, C. G., Jr.↗
NASA NTRS1977

A mission design for the Halley comet rendezvous using Ion Drive

The Ion Drive propulsion system, a derivative of the old Solar Electric Propulsion (SEP) technology is considered adequate to perform all mission objectives of a proposed Halley's comet rendezvous (scheduled for launch in 1982) except one: control of thermal energy from the concentrating solar arrays. This problem can be solved, however, by adding a separable tail probe to the baseline system. The system consists of an Ion Propulsion Module (IPM) and a Mission Module (MM). Scientific objectives include a determination of the structure of the comet nucleus, an evaluation of nucleus evolution, an assay of the comet's atmosphere and ionosphere, and a study of the interaction between the comet and the interplanetary medium. Attention is given to the navigation parameters necessary for heliocentric transfer and post-rendezvous circumnavigation of the comet.

Boain, R. J.↗