Mr. Travis R. Brashears Profile

Travis R. Brashears

at SpaceX

SPIE Involvement:

Author

Publications (19)

Proceedings Article | 13 March 2024 Presentation

Achieving 99% link uptime on a fleet of 100G space laser inter-satellite links in LEO

Travis Brashears

Proceedings Volume 12877, 1287702 (2024) https://doi.org/10.1117/12.3005057

KEYWORDS: Free space optical communications, Telecommunications, Satellites, Reliability, Optical design, Optical actuators, Manufacturing, Internet, Design and modelling, Data transmission

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Proceedings Article | 2 October 2018 Presentation + Paper

Remote Laser Evaporative Molecular Absorption (R-LEMA) spectroscopy laboratory experiments

Jonathan Madajian, Gary Hughes, Benton Miller, Yu Wang, Dane Brouwer, Alexander Cohen, Jessie Su, William Strickland, Prashant Srinivasan, Travis Brashears, Nicholas Rupert, Philip Lubin

Proceedings Volume 10769, 107690N (2018) https://doi.org/10.1117/12.2322105

KEYWORDS: Spectroscopy, Infrared spectroscopy, FT-IR spectroscopy, Molecular spectroscopy, Molecules, Molecular lasers, Laser induced breakdown spectroscopy, Infrared radiation, Absorption, Black bodies

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Proceedings Article | 19 September 2017 Presentation

NEO deflection by laser ablation: experimental results (Conference Presentation)

Jessie Su, Nicholas Rupert, Jonathan Madajian, Travis Brashears, Gary Hughes, Philip Lubin

Proceedings Volume 10401, 1040103 (2017) https://doi.org/10.1117/12.2273588

KEYWORDS: Asteroids, Laser ablation, Directed energy weapons, Phased arrays, Defense and security, Telecommunications, Fiber optic communications, Defense technologies, Laser energy, Comets

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Proceedings Article | 5 September 2017 Presentation + Paper

Near-field optical model for directed energy-propelled spacecrafts

Amber Sucich, Tomas Snyder, Gary Hughes, Prashant Srinivasan, Philip Lubin, Qicheng Zhang, Alexander Cohen, Jonathan Madajian, Travis Brashears, Nic Rupert

Proceedings Volume 10401, 1040107 (2017) https://doi.org/10.1117/12.2274692

KEYWORDS: Space operations, Near field, Directed energy weapons, Geometrical optics, Near field optics, Phased array optics, Systems modeling, Wafer-level optics, Laser propulsion, Reflectivity

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Proceedings Article | 19 September 2016 Paper

LAST: Laser Array Space Telescope

Jonathan Madajian, Alexander Cohen, Rebecca Hwang, Chase Bishman, Rachel Reyes, Miguel Bautista, Ryan Tsukamoto, Brandon Pon, Dylan Vanmali, Xu Xu, Nicholas Rommelfanger, Ian Ho, Lucas Lin, Michael Prazak, Patrick Ruehl, Travis Brashears, Nic Rupert, Philip Lubin

Proceedings Volume 9981, 99810B (2016) https://doi.org/10.1117/12.2238453

KEYWORDS: Phased arrays, Space telescopes, Telescopes, Space operations, James Webb Space Telescope, Asteroids, Phase shifts, Computer aided design, Phased array optics, Optical instrument design

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Proceedings Article | 19 September 2016 Paper

Stability of laser-propelled wafer satellites

Prashant Srinivasan, Gary Hughes, Philip Lubin, Qicheng Zhang, Jonathan Madajian, Travis Brashears, Neeraj Kulkarni, Alexander Cohen, Janelle Griswold

Proceedings Volume 9981, 998105 (2016) https://doi.org/10.1117/12.2237715

KEYWORDS: Space operations, Semiconducting wafers, Laser stabilization, Satellites, Directed energy weapons, 3D modeling, Mirrors, Photons, Reflectivity, Motion models

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Proceedings Article | 19 September 2016 Paper

Target tracking and pointing for arrays of phase-locked lasers

Van Macasaet, Gary Hughes, Philip Lubin, Jonathan Madajian, Qicheng Zhang, Janelle Griswold, Neeraj Kulkarni, Alexander Cohen, Travis Brashears

Proceedings Volume 9981, 998102 (2016) https://doi.org/10.1117/12.2237694

KEYWORDS: Sensors, Asteroids, Reflectivity, Control systems, Phased arrays, Position sensors, Beam splitters, Fiber lasers, Fiber amplifiers, Photodiodes

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Proceedings Article | 19 September 2016 Paper

Remote laser evaporative molecular absorption spectroscopy

Gary Hughes, Philip Lubin, Alexander Cohen, Jonathan Madajian, Neeraj Kulkarni, Qicheng Zhang, Janelle Griswold, Travis Brashears

Proceedings Volume 9981, 99810J (2016) https://doi.org/10.1117/12.2242730

KEYWORDS: Absorption, Black bodies, Molecular lasers, Spectroscopy, Molecular spectroscopy, Asteroids, Space operations, Comets, Laser induced breakdown spectroscopy, Solar system

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Proceedings Article | 19 September 2016 Paper

Building the future of WaferSat spacecraft for relativistic spacecraft

Travis Brashears, Philip Lubin, Nic Rupert, Eric Stanton, Amal Mehta, Patrick Knowles, Gary Hughes

Proceedings Volume 9981, 998104 (2016) https://doi.org/10.1117/12.2238471

KEYWORDS: Space operations, Semiconducting wafers, Sensors, Prototyping, Electronics, Magnetometers, Laser communications, Silicon, Space telescopes, Telescopes

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Proceedings Article | 19 September 2016 Paper

Directed energy deflection laboratory measurements of common space based targets

Travis Brashears, Philip Lubin, Gary Hughes, Peter Meinhold, Payton Batliner, Caio Motta, Jonathan Madajian, Whitaker Mercer, Patrick Knowles

Proceedings Volume 9981, 998103 (2016) https://doi.org/10.1117/12.2238462

KEYWORDS: Asteroids, Directed energy weapons, Laser ablation, Numerical simulations, Sensors, Quartz, Fiber lasers, Mirrors, Fiber coupled lasers, 3D modeling

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We report on laboratory studies of the effectiveness of directed energy planetary defense as a part of the DE-STAR (Directed Energy System for Targeting of Asteroids and exploRation) program. DE-STAR and DE-STARLITE are directed energy “stand-off” and “stand-on” programs, respectively. These systems consist of a modular array of kilowatt-class lasers powered by photovoltaics, and are capable of heating a spot on the surface of an asteroid to the point of vaporization. Mass ejection, as a plume of evaporated material, creates a reactionary thrust capable of diverting the asteroid’s orbit. In a series of papers, we have developed a theoretical basis and described numerical simulations for determining the thrust produced by material evaporating from the surface of an asteroid. In the DESTAR concept, the asteroid itself is used as the deflection “propellant”. This study presents results of experiments designed to measure the thrust created by evaporation from a laser directed energy spot. We constructed a vacuum chamber to simulate space conditions, and installed a torsion balance that holds a common space target sample. The sample is illuminated with a fiber array laser with flux levels up to 60 MW/m² , which allows us to simulate a mission level flux but on a small scale. We use a separate laser as well as a position sensitive centroid detector to readout the angular motion of the torsion balance and can thus determine the thrust. We compare the measured thrust to the models. Our theoretical models indicate a coupling coefficient well in excess of 100 μN/W_optical, though we assume a more conservative value of 80 μN/W_optical and then degrade this with an optical “encircled energy” efficiency of 0.75 to 60 μN/W_optical in our deflection modeling. Our measurements discussed here yield about 45 μN/W_absorbed as a reasonable lower limit to the thrust per optical watt absorbed. Results vary depending on the material tested and are limited to measurements of 1 axis, so further tests must be performed.

Proceedings Article | 15 March 2016 Paper

A fast high-precision six-degree-of-freedom relative position sensor

Gary Hughes, Van Macasaet, Janelle Griswold, Claudia Sison, Philip Lubin, Peter Meinhold, Jonathan Suen, Travis Brashears, Qicheng Zhang, Jonathan Madajian

Proceedings Volume 9754, 975403 (2016) https://doi.org/10.1117/12.2211372

KEYWORDS: Reflectivity, Metrology, Photodiodes, Feedback control, Sensors, Photonic devices, Position sensors, Laser metrology, Laser systems engineering, Precision measurement, Reflectors, Target acquisition, Calibration, Laser interferometry

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Proceedings Article | 9 September 2015 Paper

Directed energy deflection laboratory measurements

Travis Brashears, Phillip Lubin, Gary Hughes, Peter Meinhold, Jonathan Suen, Payton Batliner, Caio Motta, Janelle Griswold, Miikka Kangas, Isbella Johansson, Yusuf Alnawakhtha, Kenyon Prater, Alex Lang, Jonathan Madajian

Proceedings Volume 9616, 961605 (2015) https://doi.org/10.1117/12.2187094

KEYWORDS: Asteroids, Laser ablation, Directed energy weapons, Sensors, Quartz, Fiber lasers, 3D modeling, Mirrors, Numerical simulations, Thermal modeling

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Proceedings Article | 8 September 2015 Paper

Simulations of directed energy thrust on rotating asteroids

Janelle Griswold, Jonathan Madajian, Isabella Johansson, Krysten Pfau, Philip Lubin, Gary Hughes, Aidan Gilkes, Peter Meinhold, Caio Motta, Travis Brashears, Qicheng Zhang

Proceedings Volume 9616, 961606 (2015) https://doi.org/10.1117/12.2188476

KEYWORDS: Asteroids, Medium wave, 3D modeling, Directed energy weapons, Thermal modeling, Optical spheres, Silica, Phase shifts, Phased arrays, Thermal effects

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Proceedings Article | 1 September 2015 Paper

Solar lens mission concept for interstellar exploration

Travis Brashears, Philip Lubin, Slava Turyshev, Michael Shao, Qicheng Zhang

Proceedings Volume 9616, 96160A (2015) https://doi.org/10.1117/12.2189019

KEYWORDS: Semiconducting wafers, Space operations, Sun, Directed energy weapons, Solar energy, Sensors, Stars, CMOS sensors, Computer aided design, Space reconnaissance

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Proceedings Article | 1 September 2015 Paper

Local phase control for a planar array of fiber laser amplifiers

Patrick Steffanic, Benjamin Johannes, Claudia Sison, Gary Hughes, Philip Lubin, Peter Meinhold, Jonathan Suen, Hugh O'Neill, Miikka Kangas, Travis Brashears, Qicheng Zhang, Janelle Griswold, Jordan Riley, Caio Motta

Proceedings Volume 9616, 961607 (2015) https://doi.org/10.1117/12.2189821

KEYWORDS: Control systems, Sensors, Fiber amplifiers, Fiber lasers, Phased arrays, Calibration, Beam splitters, Phased array optics, Feedback control, Asteroids

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Proceedings Article | 1 September 2015 Paper

Directed energy interstellar propulsion of wafersats

Travis Brashears, Philip Lubin, Gary Hughes, Kyle McDonough, Sebastian Arias, Alex Lang, Caio Motta, Peter Meinhold, Payton Batliner, Janelle Griswold, Qicheng Zhang, Yusuf Alnawakhtha, Kenyon Prater, Jonathan Madajian, Olivia Sturman, Jana Gergieva, Aidan Gilkes, Bret Silverstein

Proceedings Volume 9616, 961609 (2015) https://doi.org/10.1117/12.2189005

KEYWORDS: Semiconducting wafers, Space operations, Reflectors, Stars, Photovoltaics, Sensors, Solar system, Telecommunications, Microelectromechanical systems, Clouds

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In the nearly 60 years of spaceflight we have accomplished wonderful feats of exploration and shown the incredible spirit of the human drive to explore and understand our universe. Yet in those 60 years we have barely left our solar system with the Voyager 1 spacecraft launched in 1977 finally leaving the solar system after 37 years of flight at a speed of 17 km/s or less than 0.006% the speed of light. As remarkable as this is, we will never reach even the nearest stars with our current propulsion technology in even 10 millennium. We have to radically rethink our strategy or give up our dreams of reaching the stars, or wait for technology that does not exist. While we all dream of human spaceflight to the stars in a way romanticized in books and movies, it is not within our power to do so, nor it is clear that this is the path we should choose. We posit a technological path forward, that while not simple; it is within our technological reach. We propose a roadmap to a program that will lead to sending relativistic probes to the nearest stars and will open up a vast array of possibilities of flight both within our solar system and far beyond. Spacecraft from gram level complete spacecraft on a wafer (“wafer sats”) that reach more than ¼ c and reach the nearest star in 15 years to spacecraft with masses more than 10⁵ kg (100 tons) that can reach speeds of near 1000 km/s such systems can be propelled to speeds currently unimaginable with our existing propulsion technologies. To do so requires a fundamental change in our thinking of both propulsion and in many cases what a spacecraft is. In addition to larger spacecraft, some capable of transporting humans, we consider functional spacecraft on a wafer, including integrated optical communications, optical systems and sensors combined with directed energy propulsion. Since “at home” the costs can be amortized over a very large number of missions. The human factor of exploring the nearest stars and exo-planets would be a profound voyage for humanity, one whose non-scientific implications would be enormous. It is time to begin this inevitable journey beyond our home.

Proceedings Article | 1 September 2015 Paper

Stand-off molecular composition analysis

Gary Hughes, Philip Lubin, Peter Meinhold, Hugh O'Neill, Travis Brashears, Qicheng Zhang, Janelle Griswold, Jordan Riley, Caio Motta

Proceedings Volume 9616, 961603 (2015) https://doi.org/10.1117/12.2186795

KEYWORDS: Absorption, Asteroids, Directed energy weapons, Black bodies, Clouds, Solar system, Molecular lasers, Spectroscopy, Telescopes, Stars

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Proceedings Article | 17 September 2014 Paper

Effects of asteroid rotation on directed energy deflection

Isabella Johansson, Tatiana Tsareva, Janelle Griswold, Philip Lubin, Gary Hughes, Hugh O'Neill, Peter Meinhold, Jonathan Suen, Qicheng Zhang, Jordan Riley, Carl Melis, Kevin Walsh, Travis Brashears, Justin Bollag, Shana Mathew, J. Bible

Proceedings Volume 9226, 922607 (2014) https://doi.org/10.1117/12.2061368

KEYWORDS: Asteroids, Directed energy weapons, Mirrors, Silica, 3D modeling, Ions, Sun, Thermal modeling, Solids, Laser energy

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Proceedings Article | 17 September 2014 Paper

DE-STARLITE - A Directed Energy Planetary Defense Mission

Kelly Kosmo, Mark Pryor, Philip Lubin, Gary Hughes, Hugh O'Neill, Peter Meinhold, Jonathan Suen, Jordan Riley, Janelle Griswold, Brianna Cook, Isabella Johansson, Qicheng Zhang, Kevin Walsh, Carl Melis, Miikka Kangas, J. Bible, Caio Motta, Travis Brashears, Shana Mathew, Justin Bollag

Proceedings Volume 9226, 922604 (2014) https://doi.org/10.1117/12.2059959

KEYWORDS: Asteroids, Space operations, Ions, Phased arrays, Laser ablation, Directed energy weapons, Phased array optics, Laser amplifiers, Photovoltaics, Solar cells

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Showing 5 of 19 publications

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