The Large Optical Test and Integration Site (LOTIS) Facility at Lockheed Martin Space Systems Company in Sunnyvale, CA has been design specifically to accommodate assembly, integration, and testing of optical payloads from as small as 1 meter class apertures to as large as 6 meters. The facility has successfully reached initial operational capability and a basic overview of the LOTIS Facility has been previously reported including wavefront performance [1], its potential for optical payload testing has been previously reported [2]. The facility has been engineered from the foundation up to provide an ideal single location for optical payloads including details such as crane access, clean room space and levels, vibration levels, and atmospheric turbulence levels within the facility especially the interior of the vacuum chamber containing the 6.5 meter collimator. This paper will present and overview of the facility in general and then present results of the vibration isolation bench performance and resulting line of sight jitter of the collimator, as well as atmospheric turbulence measurements within the chamber.
The Large Optical Test and Integration Site (LOTIS) at the Lockheed Martin Space Systems
Company in Sunnyvale, CA, has successfully reached Initial Operational Capability (IOC).
LOTIS is designed for the verification and testing of optical systems. The facility consists of a
large, temperature stabilized vacuum chamber that also functions as a class 10k cleanroom.
Within this chamber and atop an advanced vibration-isolation bench are the 6.5 meter diameter
LOTIS Collimator and Scene Generator, LOTIS alignment and support equipment. IOC included
completion of the entire facility as well as operation of the LOTIS collimator in air. Wavefront
properties of the collimator will be described as well as facility vibration isolation properties and
turbulence levels within the collimator test chamber. User-specific test capabilities will also be
addressed for two major areas of concern.
Lockheed Martin Space Systems Company has completed the Large Optical Test and Integration Site (LOTIS) at its
Sunnyvale, CA campus. Central to the LOTIS testing facility is a 6.5-meter diameter optical collimator housed in a
large, temperature controlled and vibration isolated high-vacuum chamber. A measurement has been made of the
atmospheric turbulence inside the LOTIS vacuum chamber testing environment at ambient pressure and temperature
near floor level where distorting turbulence may be most persistent. Turbulence is one of the many components that
define the overall LOTIS Collimator optical testing capabilities at ambient air pressure. Experimental measurements
have been made with a non-phase-shifting Fizeau interferometer along a 50-foot horizontal propagation path in double
pass. Results presented here represent root-mean-square (RMS) wavefront error over an 18-inch aperture and the
corresponding atmospheric coherence length, ro (Fried's parameter). In addition, an analysis was performed to calculate
the optical line-of-sight jitter response of the LOTIS Collimator system and facility due to base-level vibration
disturbances. Vibration survey measurements were made using accelerometers mounted to the vacuum chamber
foundation to create a Power Spectral Density (PSD) plot of the measured seismic and vacuum chamber mechanically
induced vibration disturbances. The measured PSD was used as the base input to a system-level finite element model
that included the LOTIS Collimator, the Flat Mirror Positioning structure and a generic Unit Under Test all mounted on
the LOTIS Vibration Isolation Bench to assess the whole system jitter response. Results presented here represent the
RMS jitter in nanoradians through the optical path of the LOTIS Collimator due to base-level induced seismic and
chamber mechanical vibrations.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.