Benjamin Longmier

Benjamin Longmier

San Francisco Bay Area
10K followers 500+ connections

About

Connecting mobile phones to satellites around the world.

Activity

10K followers

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Experience

  • SpaceX Graphic
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    Mountain View, CA

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    Ann Arbor, MI

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    Cupertino, CA

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    Ann Arbor, MI

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    Pasadena, CA

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    Houston, Texas Area

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Education

Publications

  • Initial operation of the CubeSat Ambipolar Thruster

    2015 IEEE International Conference on Plasma Sciences (ICOPS)

    Operation and characterization of the CubeSat Ambipolar Thruster (CAT), a miniature helicon electric propulsion device, is presented.

    See publication
  • New Low-Power Plasma Thruster for Nanosatellites

    50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

    The CubeSat Ambipolar Thruster is a new, electrodeless, permanent magnet, helicon
    thruster specifically designed for the constraints of a nanosatellite. The design processes
    is outlined, indicating expected thrust, Isp, and efficiency of ~ 1 mN, ~ 1000 s, and 20%,
    respectively. The major components of the thruster - quartz plasma liner, helical half-twist
    antenna, permanent magnets, and Faraday shield - are described. Finite element magnetic
    field simulations were compared to…

    The CubeSat Ambipolar Thruster is a new, electrodeless, permanent magnet, helicon
    thruster specifically designed for the constraints of a nanosatellite. The design processes
    is outlined, indicating expected thrust, Isp, and efficiency of ~ 1 mN, ~ 1000 s, and 20%,
    respectively. The major components of the thruster - quartz plasma liner, helical half-twist
    antenna, permanent magnets, and Faraday shield - are described. Finite element magnetic
    field simulations were compared to magnetometer measurements of the prototype device
    and showed agreement to within 5%. Initial testing on xenon demonstrated ignition at
    < 50 W. The electrodeless design enables the use of a wide variety of propellants and a
    discussion of iodine's potential as a propellant is included.

    Paper No. AIAA 2014-3914

  • VASIMR® Spaceflight Engine System Mass Study and Scaling with Power.

    33rd International Electric Propulsion Conference

    Mission planners require mass values of electric propulsion systems with scaling formulas as a function of input power in order to develop full spacecraft mass models and mission architectures. We develop a simplified model for a complete VASIMR® single-core spaceflight engine system called TC-1. This model is valid in the power domain of 50 to 250 kW and maintains variable specific impulse control over the range of 3000 to 5000 s using argon propellant at a selected constant total power. The…

    Mission planners require mass values of electric propulsion systems with scaling formulas as a function of input power in order to develop full spacecraft mass models and mission architectures. We develop a simplified model for a complete VASIMR® single-core spaceflight engine system called TC-1. This model is valid in the power domain of 50 to 250 kW and maintains variable specific impulse control over the range of 3000 to 5000 s using argon propellant at a selected constant total power. The model is based on commercial and laboratory hardware, detailed designs, and parametric modeling. The resultant model for the specific mass,  = A + B/Pe , is a
    simple inverse linear relationship with a constant component, A = 1.2 ± 0.1 kg/kW, and a fixed mass component, B = 444 ± 44 kg, divided by the input electrical power, Pe [kW]. The system  ranges from 10 ± 1 down to 3 ± 0.3 kg/kW with 50 to 250 kW, respectively. If a fixed Isp is selected at 5000 s,  is as low as 2.7 ± 0.3 kg/kW at 250 kW.

    See publication
  • High Altitude

    Horizons Vol. 37 Number 2

Patents

Projects

  • Kickstarter - CAT: Launch a Water-Propelled Satellite into Deep Space

    Kickstarter crowdfunding project: Join the first crowdsourced mission to explore a destination of your choice in the far reaches of space. Goal $50k, fundraising in process Dec 2-20, 2013. Kickstarter "Project of the Day" and over 70% to funding goal on day 2 of campaign.

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    See project
  • High Altitude Balloon Club

    - Present

    A student organization designed to study the nature and dynamics of upper atmospheric and near space enviornnments by means of lighter-than-air transportation.

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  • HELIOS/PHOENIX Project

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    • Nominated to be Chief Engineer—collaborated with engineering sub teams to design rocket (HELIOS) and glider payload (PHOENIX)
    • Assisted with design and fabrication on all engineering sub teams
    o Structures: Fabricated PHOENIX’s fuselage using handmade composite materials
    o Aerodynamics: Designed parts for PHOENIX in NX used for wing deployment
    o Propulsion: Performed solid motor fabrication and testing
    • Competed in Intercollegiate Rocket Engineering Competition (IREC) for the…

    • Nominated to be Chief Engineer—collaborated with engineering sub teams to design rocket (HELIOS) and glider payload (PHOENIX)
    • Assisted with design and fabrication on all engineering sub teams
    o Structures: Fabricated PHOENIX’s fuselage using handmade composite materials
    o Aerodynamics: Designed parts for PHOENIX in NX used for wing deployment
    o Propulsion: Performed solid motor fabrication and testing
    • Competed in Intercollegiate Rocket Engineering Competition (IREC) for the first time, against university teams around the world, and placed 5th out of 20 teams with an altitude of 7,600 feet.

    At apogee, PHOENIX would ideally be deployed and autonomously controlled to fly back to the launch location. Unfortunately, we ran into technical difficulties with the glider so we weren't able to fly it during competition.

    Other creators
  • Project Aether Aurora Alaska

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    A student based project in collaboration with Project Aether to understand the nature of the aurora borealis in Fairbanks, Alaska. Students designed science experiments specifically designed to study properties of the auroras. This project was lead by Dr. Benjamin Longmier of Project Aether.

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    See project

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