The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform

David R. Perkins - One of the best experts on this subject based on the ideXlab platform.

  • Upper stage options for reusable launch vehicle “pop-up” missions
    Space technology and applications international forum (STAIF - 97), 1997
    Co-Authors: James B. Eckmann, Roy B. Cotta, Leo W. Matuszak, David R. Perkins
    Abstract:

    Suborbital separation of an expendable upper stage from a small, single-stage Reusable Launch Vehicle (RLV) to transfer Spacecraft into Geosynchronous Equatorial Orbit (GEO) was investigated and found to significantly increase Spacecraft Mass into GEO (over 400%) although operational issues exist. An assessment of propulsion system options for this “Pop-Up” Mission was performed to determine the propellant combinations, stage configurations, and propulsion technologies that maximize Spacecraft Mass and minimize size. Propellants included earth and space storable combinations, cryogenic LH2/LO2, and Class 1.3 solids. Stage configurations employing cylindrical metal and overwrapped tanks, isogrid tanks, and toroidal tanks were considered. Non-toxic earth storable propellants provided comparable performance (5–10%) to existing storables while the use of pressure-fed engines gave about 15% lower performance than pump-fed. Solid stage performance was within 5% of existing storable propellants. Stages employing...

  • Upper stage options for reusable launch vehicle {open_quotes}pop-up{close_quotes} missions
    1997
    Co-Authors: James B. Eckmann, Roy B. Cotta, Leo W. Matuszak, David R. Perkins
    Abstract:

    Suborbital separation of an expendable upper stage from a small, single-stage Reusable Launch Vehicle (RLV) to transfer Spacecraft into Geosynchronous Equatorial Orbit (GEO) was investigated and found to significantly increase Spacecraft Mass into GEO (over 400{percent}) although operational issues exist. An assessment of propulsion system options for this {open_quotes}Pop-Up{close_quotes} Mission was performed to determine the propellant combinations, stage configurations, and propulsion technologies that maximize Spacecraft Mass and minimize size. Propellants included earth and space storable combinations, cryogenic LH{sub 2}/LO{sub 2}, and Class 1.3 solids. Stage configurations employing cylindrical metal and overwrapped tanks, isogrid tanks, and toroidal tanks were considered. Non-toxic earth storable propellants provided comparable performance (5{endash}10{percent}) to existing storables while the use of pressure-fed engines gave about 15{percent} lower performance than pump-fed. Solid stage performance was within 5{percent} of existing storable propellants. Stages employing toroidal tanks packaged more efficiently in length constrained RLV payload bays than 4-cylindrical tank configurations, giving up to 30{percent} greater Mass into GEO. The use of Extendable Exit Cones (EEC) for length constrained cases resulted in about 5{endash}10{percent} higher stage performance. {copyright} {ital 1997 American Institute of Physics.}

M. Enoch - One of the best experts on this subject based on the ideXlab platform.

  • Optical communications for deep space missions
    IEEE Communications Magazine, 2000
    Co-Authors: K. Wilson, M. Enoch
    Abstract:

    The Jet Propulsion Laboratory has had a long interest in optical communications for use in deep space exploration missions. Laser communication technology offers the promise of significant advantages over RF in terms of communication system performance, and Spacecraft Mass and power savings. This paper describes the activities at JPL to evaluate optical communication systems for use on deep space exploration Spacecraft.

James B. Eckmann - One of the best experts on this subject based on the ideXlab platform.

  • Upper stage options for reusable launch vehicle “pop-up” missions
    Space technology and applications international forum (STAIF - 97), 1997
    Co-Authors: James B. Eckmann, Roy B. Cotta, Leo W. Matuszak, David R. Perkins
    Abstract:

    Suborbital separation of an expendable upper stage from a small, single-stage Reusable Launch Vehicle (RLV) to transfer Spacecraft into Geosynchronous Equatorial Orbit (GEO) was investigated and found to significantly increase Spacecraft Mass into GEO (over 400%) although operational issues exist. An assessment of propulsion system options for this “Pop-Up” Mission was performed to determine the propellant combinations, stage configurations, and propulsion technologies that maximize Spacecraft Mass and minimize size. Propellants included earth and space storable combinations, cryogenic LH2/LO2, and Class 1.3 solids. Stage configurations employing cylindrical metal and overwrapped tanks, isogrid tanks, and toroidal tanks were considered. Non-toxic earth storable propellants provided comparable performance (5–10%) to existing storables while the use of pressure-fed engines gave about 15% lower performance than pump-fed. Solid stage performance was within 5% of existing storable propellants. Stages employing...

  • Upper stage options for reusable launch vehicle {open_quotes}pop-up{close_quotes} missions
    1997
    Co-Authors: James B. Eckmann, Roy B. Cotta, Leo W. Matuszak, David R. Perkins
    Abstract:

    Suborbital separation of an expendable upper stage from a small, single-stage Reusable Launch Vehicle (RLV) to transfer Spacecraft into Geosynchronous Equatorial Orbit (GEO) was investigated and found to significantly increase Spacecraft Mass into GEO (over 400{percent}) although operational issues exist. An assessment of propulsion system options for this {open_quotes}Pop-Up{close_quotes} Mission was performed to determine the propellant combinations, stage configurations, and propulsion technologies that maximize Spacecraft Mass and minimize size. Propellants included earth and space storable combinations, cryogenic LH{sub 2}/LO{sub 2}, and Class 1.3 solids. Stage configurations employing cylindrical metal and overwrapped tanks, isogrid tanks, and toroidal tanks were considered. Non-toxic earth storable propellants provided comparable performance (5{endash}10{percent}) to existing storables while the use of pressure-fed engines gave about 15{percent} lower performance than pump-fed. Solid stage performance was within 5{percent} of existing storable propellants. Stages employing toroidal tanks packaged more efficiently in length constrained RLV payload bays than 4-cylindrical tank configurations, giving up to 30{percent} greater Mass into GEO. The use of Extendable Exit Cones (EEC) for length constrained cases resulted in about 5{endash}10{percent} higher stage performance. {copyright} {ital 1997 American Institute of Physics.}

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

  • Pulsed Plasma Thruster Technology
    2018
    Co-Authors: Nasa
    Abstract:

    The continuing emphasis on reducing costs and downsizing Spacecraft is forcing increased emphasis on reducing the subsystem Mass and integration costs. For many commercial, scientific, and Department of Defense space missions, onboard propulsion is either the predominant Spacecraft Mass or it limits the Spacecraft lifetime. Electromagnetic-pulsed-plasma thrusters (PPT's) offer the combined benefits of extremely low average electric power requirements (1 to 150 W), high specific impulse (approx. 1000 sec), and system simplicity derived from the use of an inert solid propellant. Potential applications range from orbit insertion and maintenance of small satellites to attitude control for large geostationary communications satellites.

  • Spacecraft Mass estimation, relationships and engine data: Task 1.1 of the lunar base systems study
    2013
    Co-Authors: Nasa
    Abstract:

    A collection of scaling equations, weight statements, scaling factors, etc., useful for doing conceptual designs of Spacecraft are given. Rules of thumb and methods of calculating quantities of interest are provided. Basic relationships for conventional, and several non-conventional, propulsion systems (nuclear, solar electric and solar thermal) are included. The equations and other data were taken from a number of sources and are not at all consistent with each other in level of detail or method, but provide useful references for early estimation purposes.

Austin Nicholas - One of the best experts on this subject based on the ideXlab platform.

  • Round-Trip Solar Electric Propulsion Missions for Mars Sample Return
    2014
    Co-Authors: Zachary J. Bailey, Erick J. Sturm, Theresa Kowalkowski, Robert E. Lock, Ryan Woolley, Austin Nicholas
    Abstract:

    Mars Sample Return (MSR) missions could benefit from the high specific impulse of Solar Electric Propulsion (SEP) to achieve lower launch Masses than with chemical propulsion. SEP presents formulation challenges due to the coupled nature of launch vehicle performance, propulsion system, power system, and mission timeline. This paper describes a SEP orbiter-sizing tool, which models Spacecraft Mass & timeline in conjunction with low thrust round-trip Earth-Mars trajectories, and presents selected concept designs. A variety of system designs are possible for SEP MSR orbiters, with large dry Mass allocations, similar round-trip durations to chemical orbiters, and reduced design variability between opportunities.