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Michael Cupples - One of the best experts on this subject based on the ideXlab platform.

  • low thrust trajectory optimization procedure for gravity assist outer planet missions
    Journal of Spacecraft and Rockets, 2006
    Co-Authors: Byoungsam Woo, Victoria L Coverstone, Michael Cupples
    Abstract:

    A hybrid trajectory optimization procedure for a class of Solar-Electric-Propulsion, gravity-assist, outer-planet missions is presented. The parameter space of a target mission is often nonconvex and a calculus-of-variations-based optimization algorithm suffers difficulties efficiently exploring this space. A hybrid procedure using a genetic algorithm to drive a calculus-of-variations program is developed to automate searching over a reduced parameter space. Employing the hybrid procedure, the delivered mass profiles of a Uranus and Pluto mission are generated more quickly than by using the calculus-of-variations optimization algorithm alone.

  • Application of Solar Electric Propulsion to a Comet Surface Sample Return Mission
    Journal of Spacecraft and Rockets, 2006
    Co-Authors: Byoungsam Woo, Victoria L Coverstone, Michael Cupples
    Abstract:

    Current NSTAR (planned for the Discovery Mission: Dawn) and NASA's Evolutionary Xenon Thruster based Propulsion systems were compared for a comet surface sample return mission to Tempe1 1. Mission and systems analyses were conducted over a range of array power for each Propulsion system with an array of 12 kW EOL at 1 AU chosen for a baseline. Engine configurations investigated for NSTAR included 4 operational engines with 1 spare and 5 operational engines with 1 spare. The NEXT configuration investigated included 2 operational engines plus 1 spare, with performance estimated for high thrust and high Isp throttling modes. Figures of merit for this comparison include Solar Electric Propulsion dry mass, average engine throughput, and net non-Propulsion payload returned to Earth flyby.

  • trajectory and system analysis for outer planet Solar Electric Propulsion missions
    Journal of Spacecraft and Rockets, 2005
    Co-Authors: Byoungsam Woo, Victoria L Coverstone, John W Hartmann, Michael Cupples
    Abstract:

    Outer-planet mission and systems analyses are performed using three next generation Solar-Electric ion thruster models. The impact of variations in thruster model, flight time, launch vehicle, Propulsion and power systems characteristics is investigated. All presented trajectories have a single Venus gravity assist and maximize the delivered mass to Saturn or Neptune. The effect of revolution ratio - the ratio of Venusian orbital period to the flight time between launch and flyby dates - is also discussed.

  • effects of gravity assist timing on outer planet missions using Solar Electric Propulsion
    Collection of Technical Papers - AIAA AAS Astrodynamics Specialist Conference, 2004
    Co-Authors: Byoungsam Woo, Victoria L Coverstone, Michael Cupples
    Abstract:

    Missions to the outer planets for spacecraft with a Solar-Electric Propulsion system (SEPS) and that utilize a single Venus gravity assist are investigated. The trajectories maximize the delivered mass to the target planet for a range of flight times. A comparison of the trajectory characteristics (delivered mass, launch energy and onboard propulsive energy) is made for various Venus gravity assist opportunities. Methods to estimate the delivered mass to the outer planets are developed.

  • factors influencing Solar Electric Propulsion vehicle payload delivery for outer planet missions
    Spaceflight Mechanics 2003: Proceedings of the AAS AIAA Space Flight Mechanics Meeting, 2003
    Co-Authors: Michael Cupples, Shaun E Green, Victoria L Coverstone
    Abstract:

    Systems analyses were performed for missions utilizing Solar Electric Propulsion systems to deliver payloads to outer-planet destinations. A range of mission and systems factors and their affect on the delivery capability of the Solar Electric Propulsion system was examined. The effect of varying the destination, the trip time, the launch vehicle, and gravity-assist boundary conditions was investigated. In addition, the affects of selecting Propulsion system and power systems characteristics (including primary array power variation, number of thrusters, thruster throttling mode, and thruster Isp) on delivered payload was examined.

Byoungsam Woo - One of the best experts on this subject based on the ideXlab platform.

  • low thrust trajectory optimization procedure for gravity assist outer planet missions
    Journal of Spacecraft and Rockets, 2006
    Co-Authors: Byoungsam Woo, Victoria L Coverstone, Michael Cupples
    Abstract:

    A hybrid trajectory optimization procedure for a class of Solar-Electric-Propulsion, gravity-assist, outer-planet missions is presented. The parameter space of a target mission is often nonconvex and a calculus-of-variations-based optimization algorithm suffers difficulties efficiently exploring this space. A hybrid procedure using a genetic algorithm to drive a calculus-of-variations program is developed to automate searching over a reduced parameter space. Employing the hybrid procedure, the delivered mass profiles of a Uranus and Pluto mission are generated more quickly than by using the calculus-of-variations optimization algorithm alone.

  • Application of Solar Electric Propulsion to a Comet Surface Sample Return Mission
    Journal of Spacecraft and Rockets, 2006
    Co-Authors: Byoungsam Woo, Victoria L Coverstone, Michael Cupples
    Abstract:

    Current NSTAR (planned for the Discovery Mission: Dawn) and NASA's Evolutionary Xenon Thruster based Propulsion systems were compared for a comet surface sample return mission to Tempe1 1. Mission and systems analyses were conducted over a range of array power for each Propulsion system with an array of 12 kW EOL at 1 AU chosen for a baseline. Engine configurations investigated for NSTAR included 4 operational engines with 1 spare and 5 operational engines with 1 spare. The NEXT configuration investigated included 2 operational engines plus 1 spare, with performance estimated for high thrust and high Isp throttling modes. Figures of merit for this comparison include Solar Electric Propulsion dry mass, average engine throughput, and net non-Propulsion payload returned to Earth flyby.

  • trajectory and system analysis for outer planet Solar Electric Propulsion missions
    Journal of Spacecraft and Rockets, 2005
    Co-Authors: Byoungsam Woo, Victoria L Coverstone, John W Hartmann, Michael Cupples
    Abstract:

    Outer-planet mission and systems analyses are performed using three next generation Solar-Electric ion thruster models. The impact of variations in thruster model, flight time, launch vehicle, Propulsion and power systems characteristics is investigated. All presented trajectories have a single Venus gravity assist and maximize the delivered mass to Saturn or Neptune. The effect of revolution ratio - the ratio of Venusian orbital period to the flight time between launch and flyby dates - is also discussed.

  • effects of gravity assist timing on outer planet missions using Solar Electric Propulsion
    Collection of Technical Papers - AIAA AAS Astrodynamics Specialist Conference, 2004
    Co-Authors: Byoungsam Woo, Victoria L Coverstone, Michael Cupples
    Abstract:

    Missions to the outer planets for spacecraft with a Solar-Electric Propulsion system (SEPS) and that utilize a single Venus gravity assist are investigated. The trajectories maximize the delivered mass to the target planet for a range of flight times. A comparison of the trajectory characteristics (delivered mass, launch energy and onboard propulsive energy) is made for various Venus gravity assist opportunities. Methods to estimate the delivered mass to the outer planets are developed.

Victoria L Coverstone - One of the best experts on this subject based on the ideXlab platform.

  • low thrust trajectory optimization procedure for gravity assist outer planet missions
    Journal of Spacecraft and Rockets, 2006
    Co-Authors: Byoungsam Woo, Victoria L Coverstone, Michael Cupples
    Abstract:

    A hybrid trajectory optimization procedure for a class of Solar-Electric-Propulsion, gravity-assist, outer-planet missions is presented. The parameter space of a target mission is often nonconvex and a calculus-of-variations-based optimization algorithm suffers difficulties efficiently exploring this space. A hybrid procedure using a genetic algorithm to drive a calculus-of-variations program is developed to automate searching over a reduced parameter space. Employing the hybrid procedure, the delivered mass profiles of a Uranus and Pluto mission are generated more quickly than by using the calculus-of-variations optimization algorithm alone.

  • Application of Solar Electric Propulsion to a Comet Surface Sample Return Mission
    Journal of Spacecraft and Rockets, 2006
    Co-Authors: Byoungsam Woo, Victoria L Coverstone, Michael Cupples
    Abstract:

    Current NSTAR (planned for the Discovery Mission: Dawn) and NASA's Evolutionary Xenon Thruster based Propulsion systems were compared for a comet surface sample return mission to Tempe1 1. Mission and systems analyses were conducted over a range of array power for each Propulsion system with an array of 12 kW EOL at 1 AU chosen for a baseline. Engine configurations investigated for NSTAR included 4 operational engines with 1 spare and 5 operational engines with 1 spare. The NEXT configuration investigated included 2 operational engines plus 1 spare, with performance estimated for high thrust and high Isp throttling modes. Figures of merit for this comparison include Solar Electric Propulsion dry mass, average engine throughput, and net non-Propulsion payload returned to Earth flyby.

  • trajectory and system analysis for outer planet Solar Electric Propulsion missions
    Journal of Spacecraft and Rockets, 2005
    Co-Authors: Byoungsam Woo, Victoria L Coverstone, John W Hartmann, Michael Cupples
    Abstract:

    Outer-planet mission and systems analyses are performed using three next generation Solar-Electric ion thruster models. The impact of variations in thruster model, flight time, launch vehicle, Propulsion and power systems characteristics is investigated. All presented trajectories have a single Venus gravity assist and maximize the delivered mass to Saturn or Neptune. The effect of revolution ratio - the ratio of Venusian orbital period to the flight time between launch and flyby dates - is also discussed.

  • effects of gravity assist timing on outer planet missions using Solar Electric Propulsion
    Collection of Technical Papers - AIAA AAS Astrodynamics Specialist Conference, 2004
    Co-Authors: Byoungsam Woo, Victoria L Coverstone, Michael Cupples
    Abstract:

    Missions to the outer planets for spacecraft with a Solar-Electric Propulsion system (SEPS) and that utilize a single Venus gravity assist are investigated. The trajectories maximize the delivered mass to the target planet for a range of flight times. A comparison of the trajectory characteristics (delivered mass, launch energy and onboard propulsive energy) is made for various Venus gravity assist opportunities. Methods to estimate the delivered mass to the outer planets are developed.

  • factors influencing Solar Electric Propulsion vehicle payload delivery for outer planet missions
    Spaceflight Mechanics 2003: Proceedings of the AAS AIAA Space Flight Mechanics Meeting, 2003
    Co-Authors: Michael Cupples, Shaun E Green, Victoria L Coverstone
    Abstract:

    Systems analyses were performed for missions utilizing Solar Electric Propulsion systems to deliver payloads to outer-planet destinations. A range of mission and systems factors and their affect on the delivery capability of the Solar Electric Propulsion system was examined. The effect of varying the destination, the trip time, the launch vehicle, and gravity-assist boundary conditions was investigated. In addition, the affects of selecting Propulsion system and power systems characteristics (including primary array power variation, number of thrusters, thruster throttling mode, and thruster Isp) on delivered payload was examined.

Jeannette Heiligers - One of the best experts on this subject based on the ideXlab platform.

  • trajectory design for a Solar sail mission to asteroid 2016 ho3
    Astrodynamics, 2019
    Co-Authors: Jeannette Heiligers, Juan M Fernandez, Olive R Stohlman, Keats W Wilkie
    Abstract:

    This paper proposes the use of Solar-sail technology currently under development at NASA Langley Research Center for a CubeSat rendezvous mission with asteroid 2016 HO3, a quasi-satellite of Earth. Time-optimal trajectories are sought for within a 2022–2023 launch window, starting from an assumed launcher ejection condition in the Earth-Moon system. The optimal control problem is solved through a particular implementation of a direct pseudo-spectral method for which initial guesses are generated through a relatively simple and straightforward genetic algorithm search on the optimal launch date and sail attitude. The results show that the trajectories take 2.16–4.21 years to complete, depending on the assumed Solar-sail reflectance model and Solar-sail technology. To assess the performance of Solar-sail Propulsion for this mission, the trajectory is also designed assuming the use of Solar Electric Propulsion. The resulting fuel-optimal trajectories take longer to complete than the Solar-sail trajectories and require a propellant consumption that exceeds the expected propellant capacity onboard the CubeSat. This comparison demonstrates the superior performance of Solar-sail technology for this mission.

  • Loosely-displaced geostationary orbits with hybrid sail Propulsion
    Aerospace Science and Technology, 2018
    Co-Authors: Jeannette Heiligers, Matteo Ceriotti
    Abstract:

    To overcome the congestion of geostationary orbit slots, previous work proposed to use vertically-displaced, non-Keplerian geostationary orbits by means of continuous low-thrust Propulsion in the form of hybrid Solar sail and Solar Electric Propulsion (hybrid sail). This work extends and generalizes that concept by loosening the position constraint and introducing a station-keeping box. Sub-optimal orbits are first found with an inverse method that still satisfy the geostationary position constraint (i.e., no station-keeping box), which will be referred to as ideal displaced geostationary orbits. For these sub-optimal orbits, it is found that the hybrid sail saves propellant mass compared to the pure Solar Electric Propulsion case: for Solar sail lightness numbers of up to a value of 0.2 and the most favorable time during the year (i.e., at summer solstice), the hybrid sail saves up to 71.6% propellant mass during a single day compared to the use of pure Solar Electric Propulsion. Subsequently, the sub-optimal orbits are used as a first-guess for a direct optimization algorithm based on Gauss pseudospectral transcription, which loosens the position constraint. This enables a more flexible trajectory around the ideal displaced geostationary orbit and lets the Solar sail contribute more efficiently to the required acceleration. It therefore leads to a further propellant savings of up to 73.8%. Finally, the mass budget shows that by using by using far-term Solar sail technology, the hybrid Propulsion system enables an evident reduction in the required initial mass of the spacecraft for a given payload mass with a relatively long mission duration.

  • Trajectory and spacecraft design for a pole-sitter mission
    Journal of Spacecraft and Rockets, 2014
    Co-Authors: Matteo Ceriotti, Jeannette Heiligers, Colin R. Mcinnes
    Abstract:

    This paper provides a detailed mission analysis and systems design of a pole-sitter mission. It considers a spacecraft that is continuously above either the North or South Pole and, as such, can provide real-time, continuous, and hemispherical coverage of the polar regions. Two different Propulsion strategies are proposed, which result in a near-term pole-sitter mission using Solar-Electric Propulsion and a far-term pole-sitter mission, in which the Electric thruster is hybridized with a Solar sail. For both Propulsion strategies, minimum propellant pole-sitter orbits are designed. Optimal transfers from Earth to the pole sitter are designed, assuming Soyuz and Ariane 5 launch options, and a controller is shown to be able to maintain the trajectory under unexpected conditions, such as injection errors. A detailed mass budget analysis allows for a tradeoff between mission lifetime and payload mass capacity, and candidate payloads for a range of applications are investigated. This results in a payload of ab...

  • displaced geostationary orbit design using hybrid sail Propulsion
    Journal of Guidance Control and Dynamics, 2011
    Co-Authors: Jeannette Heiligers, Matteo Ceriotti, Colin R. Mcinnes, James D. Biggs
    Abstract:

    Due to an increase in number of geostationary spacecraft and limits imposed by east-west spacing requirements, the geostationary orbit is becoming congested. To increase its capacity, this paper proposes to create new geostationary slots by displacing the geostationary orbit either out of or in the equatorial plane by means of hybrid Solar sail and Solar Electric Propulsion. To minimize propellant consumption, optimal steering laws for the Solar sail and Solar Electric Propulsion thrust vectors are derived and the performance in terms of mission lifetime is assessed. For comparison, similar analyses are performed for conventional Propulsion, including impulsive and pure Solar Electric Propulsion. It is shown that hybrid sails outperform these Propulsion techniques and that out-of-plane displacements outperform in-plane displacements. The out-of-plane case is therefore further investigated in a spacecraft mass budget to determine the payload mass capacity. Finally, two transfers that enable a further improvement of the performance of hybrid sails for the out-of-plane case are optimized using a direct pseudo-spectral method: a seasonally transit between orbits displaced above and below the equatorial plane and a transit to a parking orbit when geostationary coverage is not needed. Both transfers are shown to require only a modest propellant budget, outweighing the improvements they can establish.

Mcguire, Melissa L. - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of Near Rectilinear Halo Orbit Insertion with a 40-kW Solar Electric Propulsion System
    2018
    Co-Authors: Mcguire, Melissa L., Mccarty, Steven L., Sjauw, Waldy K., Burke, Laura M.
    Abstract:

    This paper examines low thrust trajectories for delivery of a 40-kW Solar Electric Propulsion spacecraft and potential additional payload to a desired NRHO. One option considered is a trans-lunar injection launch as a co-manifested payload on the Space Launch System. For this option, a reference trajectory is designed and a scan of launch dates is completed to understand the propellant mass sensitivity. A 15-day period cyclical variation in required propellant is observed that is attributed to Solar gravity effects. A second option considered is to launch on a smaller commercial launch vehicle to a less energetic elliptical orbit and use SEP to spiral out to NRHO. For this option, analysis is completed to understand the trades between delivered mass to NRHO, total propellant required, time of flight, and Solar array degradation. Results show that, while launching to lower altitudes can deliver greater payload mass to NRHO, significant Solar array degradation can be observed

  • Analysis of Cislunar Transfers from a Near Rectilinear Halo Orbit with High Power Solar Electric Propulsion
    2018
    Co-Authors: Burke, Laura M., Mccarty, Steven L., Mcguire, Melissa L.
    Abstract:

    As government and commercial interest in the exploration of the Moon and cislunar space has grown, Near Rectilinear Halo Orbits (NRHOs) have shown to be of particular interest as staging orbits for human exploration of the Moon. Once in such staging orbits, low thrust Solar Electric Propulsion (SEP) can enable efficient transfer to other orbits in cislunar space. This paper captures ongoing analysis to design efficient transfers of a massive spacecraft from a L2 Southern NRHO to a Distant Retrograde Orbit, L1 Northern NRHO, and Flat L2 Halo Orbit using low thrust SEP. For each transfer type, reference transfer is designed for an assumed 39 t spacecraft with 26.6 kW SEP system. For each reference transfer, analysis is completed to understand the sensitivity of the transfer to changes in initial mass and SEP power and identify the optimal number of thrusters to use for a given combination of mass and power

  • NASA GRC Compass Team Conceptual Point Design and Trades of a Hybrid Solar Electric Propulsion (SEP)/Chemical Propulsion Human Mars Deep Space Transport (DST) Vehicle
    2018
    Co-Authors: Newman J. Michael, Mcguire, Melissa L., Burke, Laura M., Martini, Michael C., Oleson, Steven R.
    Abstract:

    NASA has long been conducting studies which apply different in-space Propulsion technology assumptions to the mission of sending humans to Mars. Two of the technologies under study that are considered to be the most near-term with respect to technology readiness level (TRL) are traditional chemical Propulsion systems and high-power Solar Electric Propulsion (SEP) systems. The benefit of relatively low trip times inherent in using impulsive chemical Propulsion systems to perform the full round-trip delta V is hampered by the large propellant mass required to perform these burns for human Mars missions. SEP systems offer the benefit of much lower propellant requirements to perform the same round-trip missions, at the cost of longer trip times. Traditionally, impulsive chemical systems are better suited than SEP when used in a gravity well, and SEP systems are more efficient than traditional impulsive systems when used in interplanetary space. A mission to Mars includes both of these scenarios, and thus several NASA architecture studies performed over the last few years have looked to combine the use of both SEP and chemical Propulsion systems where they are the most beneficial to human Mars missions. This combined Propulsion system concept has been referred to as a SEP/Chem hybrid Mars Transfer Vehicle and is currently shown as the concept Deep Space Transport (DST) in the March 2017 NASA presentation to the National Aerospace Council (NAC)