Investigations on a LISA Telescope Spacer

ORAL

Abstract

The Laser Interferometer Space Antenna (LISA) is a space-based mission designed to observe gravitational waves from 0.1 mHz to 1 Hz. Using a triangular constellation of three spacecraft separated by 5x10$^{6}$ km, LISA will be able to detect the length changes between the spacecraft induced by gravitational waves. These length changes can be detected with pm/rtHz sensitivity using laser interferometry. Each spacecraft must contain two telescopes that can transmit and receive light between spacecraft. To expand and collimate the beam, a two-mirror system was designed with a primary and secondary mirror separated by a spacer. The noise requirements for LISA demand that the telescope spacer must be extremely stable. Two designs, on-axis and off-axis, are being considered for the telescope spacer. Various materials are also being examined. An on-axis silicon carbide telescope test structure was built to assess the stability of this configuration. A Michelson Interferometer was used to monitor length changes of the test structure while being cooled to space-like temperatures. Stability measurements are currently being made by locking the telescope laser to a cavity mounted on the test structure and then the beat note between the telescope laser and another cavity-locked laser is observed. A beat note between another laser locked to the Doppler-free spectral lines of iodine and the telescope laser will be used to determine the long term stability of the test structure.

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Authors

  • Aaron Spector

  • Philip Adams

    Department of Physics and Astronomy, Louisiana State University, ORNL, UT, ORNL/UT, UK, LSU, Louisiana State University, Zhejiang Normal University, Center for Computation and Technology, Louisiana State University, University of Tuebingen, Germany, Aristotle University of Thessaloniki, Greece, Max Planck Institute for Astrophysics, Max Plank Institute for Astrophysics, Laboratoire d'Astrophysique de Marseille, Albert Einstein Institute, California Institute of Technology, Dept. of Physics \& Astronomy, Louisiana State University, Baton Rouge, LA 70803, Dept. of Physics \& Astronomy, Louisiana State Univ., Baton Rouge, LA 70803, NASA Marshall Space Flight Center, Dept. of Physics \& Astronomy, Louisiana State University, Ohio State University, Wright State University, Department of Physics, North Carolina A\&T State University, Clark Atlanta University, Department of Electrical and Computer Engineering, Pennsylvania State University, University Park, P, Princeton University, University of New Orleans, Alabama A\&M University, Vanderbilt Univ., Konstanz Univ., Isik Univ., Department of Physics, Yale University

  • Philip Adams

    Department of Physics and Astronomy, Louisiana State University, ORNL, UT, ORNL/UT, UK, LSU, Louisiana State University, Zhejiang Normal University, Center for Computation and Technology, Louisiana State University, University of Tuebingen, Germany, Aristotle University of Thessaloniki, Greece, Max Planck Institute for Astrophysics, Max Plank Institute for Astrophysics, Laboratoire d'Astrophysique de Marseille, Albert Einstein Institute, California Institute of Technology, Dept. of Physics \& Astronomy, Louisiana State University, Baton Rouge, LA 70803, Dept. of Physics \& Astronomy, Louisiana State Univ., Baton Rouge, LA 70803, NASA Marshall Space Flight Center, Dept. of Physics \& Astronomy, Louisiana State University, Ohio State University, Wright State University, Department of Physics, North Carolina A\&T State University, Clark Atlanta University, Department of Electrical and Computer Engineering, Pennsylvania State University, University Park, P, Princeton University, University of New Orleans, Alabama A\&M University, Vanderbilt Univ., Konstanz Univ., Isik Univ., Department of Physics, Yale University