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Advanced Electro-Optical System [AEOS]

Advanced Electro-Optical System [AEOS] is a 3.7 Meter dedicated Electro-Optical (E-O) telescope with the following major features

  • Adaptive Optics Imaging System provides high resolution imaging and metric data on Near Earth (NE) objects
  • Longwave Infrared (LWIR) sensor provides LWIR images / temperature maps and metric data on NE objects
  • Radiometric/photometric sensor provides visible Midwave Infrared (MWIR), LWIR and signature/temperature data on NE/Deep Space (DS) objects
  • System supports Space Intelligence through high resolution E-O SOI data

The Advanced ElectroOptical System (AEOS) is a 3.67 meter telescope space surveillance system specifically designed to improve the means of collecting, and the quality of, space data at the Maui Space Surveillance Complex facility in Hawaii. Primarily intended for Department of Defense space surveillance missions, the telescope is also used by scientific and academic astronomy communities from across the United States. The origins of AEOS began in the middle of the 1980s. At that time, the Air Force was trying to develop a groundbased laser antisatellite capability. Maui appealed to AEOS planners for several reasons. Its maritime location, coupled with its 10,000 foot altitude, clear visibility, and location near the equator, made Haleakala a very stable environmental candidate. Taken together, these advantages made the site superb for routine observation of space objects. Work in support of the Western Test Range out of Vandenberg Air Force Base, California, and Barking Sands Missile Range on Kauai Island, Hawaii, and restricted airspace in this part of the Pacific Ocean also enhanced the site’s ability to meet its mission.

The existing facilities at the Maui Space Surveillance Complex included the 1.6 meter telescope, 1.2 meter twin telescopes, Laser Beam Director, Beam Director/Tracker, and the Groundbased ElectroOptical Deep Space Surveillance System, as well as a proximity to the Maui High Performance Computing Center, made Maui even more attractive. Therefore, the AEOS would optimize Maui Space Surveillance System research and development capabilities, as well as improve the quality of images taken from the ground of space objects. With the support of Hawaii’s senior United States senator, Honorable Daniel K. Inouye, who was an important member of several Senate committees, AEOS could help Hawaii transition from a tourism based economy to a high technology based economy.

When the program started, AEOS’ mission was to support space test and tracking missions for U.S. Space Command. In the past, radarbased imaging techniques had been favored by U.S. Space Command over electrooptical methods. However, electrooptical systems could produce photographic images, while radar could not. These photographic images were more amenable to the human eye than those produced through radar signatures. Benefits expected from the AEOS and enhanced Maui Space Surveillance System included mission payload assessment and space object identification for Air Force Space Command, adaptive optic research for the Air Force Research Laboratory, and use by government agencies and the national and international astronomy communities.

In the fall of 1995, the AEOS retained its research and development mission for Air Force Materiel Command, while its Air Force Space Command mission had evolved into three main areas: space intelligence, space tracking, and space control. Space tracking called for detecting and tracking objects in space, which led to the development of metrics of space objects for the catalog that the Air Force developed for the nation. Space control demanded highresolution imagery as well as good signature data to ensure positive identification of an object in space. In addition, space debris, laser experimentation, and atmospheric science work would also be performed out of the AEOS. The Air Force Research Laboratory had a Memorandum of Agreement with the University of Hawaii for cooperative research in astronomy.

At the center of the AEOS is the 3.67 meter telescope, which is the largest in the Department of Defense. The telescope’s mirror is of the thin meniscus variety, and offers significant improvements (approximately twoandahalffold) in resolution over what the existing Maui Space Surveillance System mounts could achieve before AEOS. This resolution improvement meant smaller, dimmer objects in space could be seen more clearly after AEOS became operational.

The 3.67 meter telescope was constructed by Contraves USA, which is located in Pittsburgh, Pennsylvania. The company also fabricated the mirror for the telescope. AEOS’s design optimizes its ability to track satellites. Therefore, AEOS is able to slew up to 18 degrees per second in the azimuth direction. This allows the telescope to follow a very fast moving low earth orbit satellite. The 120 ton telescope has a 1 milliradian field of view at the bent Cassegrian position, and a 0.3milliradian field of view in the coude labs.

Like the 3.5 meter telescope at Kirtland Air Force Base, New Mexico, the AEOS is housed in a domed structure that connects to laboratory space. A standard astronomical dome is a major source of bad seeing, as the dome is heated during the day and at night the warm air is trapped inside of the dome. It can only escape through the slit, which the telescope is observing through.

The AEOS dome was designed to mitigate this problem. AEOS is an opentruss telescope enclosed in a unique dome that completely lowers during operations. This design maximizes imagery under dark conditions by alleviating the issue of dome-induced turbulence which degrades imagery, but provides no sun protection during daylight.

The dome consists of two concentric cylinders with an aperture at the top. For operations this aperture opens and the dome walls lower, until the telescope emerges from the aperture. The telescope is then fully exposed to the ambient night atmosphere. With this type of dome any warm air in the dome is quickly dispersed into the ambient air. This should eliminate the major cause of dome seeing that plagues standard dome designs. A down side of this dome design is that since the dome fully retracts, the telescope is not protected from wind buffeting; in high wind situations, the dome walls are left up and the telescope observes through the aperture. This restricts viewing to within 30 degrees of zenith.

The dome was contracted to COMSAT RSI, based in Fairfax, Virginia. The 40,000squarefoot AEOS facility features a centralized coude room, located in the basement of the facility directly below the telescope. The adaptive optics reside in this coude room, and distribute the light to one of seven optics experiment suites built concentrically around the coude room. The architects for the facility are Hawaii based Gima-Yoshimori-Miyabara.

The AEOS telescope facility was designed for high angular resolution imagery. Part of that design is the inclusion of several air handling systems to maximize dome seeing. Four air conditioning units chill the telescope and dome air to the predicted nighttime temperature. There is a mirror purge system, which prevents moisture from condensing on the mirror by blowing desiccated air into the mirror cell. A laminar air system counteracts the seeing degradation effects of a warm mirror by blowing air across the face of the primary. An hour before sunset the dome is partially opened and outside air is pulled through the telescope truss structure in an effort to remove any thermal differences caused by incorrect cooling. Finally a fan pulls air through the coude tube in order to remove rising air cells.

Facility construction was handled by Kiewit Pacific and overall responsibility for construction management at the site rested with the U.S. Army Corps of Engineers, Honolulu Engineering District.

There are three mission sensors associated with AEOS. The first sensor is a longwave infrared imager which produces spatially resolved thermal images of space objects. Hughes Aircraft Company of El Segundo, California, fabricated this imager. The second sensor, a radiometer, contracted to Mission Research Corporation of Santa Barbara, California, is a multispectral sensor instrument ranging from visible through the verylongwave infrared spectral range. The third sensor is a visible imaging camera constructed as part of the adaptive optics system built by Hughes Danbury Optical Systems. Requirements for these sensors derived from stated Air Force Space Command requirements.

The Air Force Research Laboratory awarded the adaptive optics contract to Hughes Danbury Optical Systems, Danbury, Connecticut, on August 22, 1994. This system has very broad system applications. It features a closed loop bandwidth capability up to 200 hertz. This allows both military and civilian users to meet their needs: military users slewing across the sky use the higher bandwidths, while civilians, staring at a point in the sky, use the lower bandwidths. The adaptive optics package also includes a deformable mirror with 940 actuators. This is the largest such mirror made, and also the greatest number of actuators on a single such mirror.

The Observatory Control System is a command, control, communication, and data system that integrates and connects the various elements of AEOS. In addition, this system provides for physical and electronic security for all the AEOS assets. Because this system is highly interoperable and well integrated throughout the Maui Space Surveillance System, the Laboratory program office and Air Force Space Command have coordinated closely to develop the specifications for this upgrade. This allows for the Laboratory to require a standardized data format as part of the contract, which allows new equipment brought to the facility in the future to be readily integrated with the Observatory Control System. The Observatory Control System contract was awarded to Rockwell Power Systems, later renamed Rocketdyne Technical Services, which is also the site contractor at Maui.

Other contractors were involved with AEOS as well. The University of Hawaii, for example, built one of the instruments AEOS uses for astronomical applications. Lincoln Laboratory has provided technical support, particularly in relation to the adaptive optics and the sensors for the AEOS. In Albuquerque, the Air Force Research Laboratory’s Directed Energy Directorate is supported by Pantera Consulting, a small business that provides scientific and technical advisory engineering support. Logicon RDA, another Albuquerquebased system engineering and technical advisory company, has provided AFRL support on the telescope, the adaptive optics system, system engineering, sensors and the Observatory Control System. Rocketdyne Technical Services, also provides support to the Air Force Research Laboratory for system engineering, integration and test.

A ribbon-cutting ceremony was held 21 August 2008 at the Institute for Astronomy (IFA), Advanced Technology Research Center, Pukalani, Maui to officially open the Corps of Engineers built Mirror Coating Facility. The Corps’ design-build construction of the Mirror Coating facility would support the Advance Electro-Optical System (AEOS) telescope at the Maui Space Surveillance Complex. This project was programmed as a Fiscal Year 2005 military construction congressional addition with the help of U.S. Senator Daniel K. Inouye and was awarded to San Juan Construction, Inc. of Honolulu in December 2005 for the design and construction of the facility for $4,607,000.

Upgrading AEOS to a daylight imaging asset required sun mitigation to prevent thermal damage to the telescope, to reduce sky background, and to prevent stray light degradation of collected imagery. The Air Force Research Laboratory Directed Energy Directorate designed a sun mitigation system to increase daytime use and significantly improve MSSC’s daylight imaging resolution capability.

Two sun mitigation options were investigated in a study 2012-2013 to determine which method best improved imagery by reducing stray and background light. The first option is the traditional approach for mitigating stray light, which is to retrofit AEOS with a baffle that covers the truss structure. Unfortunately, this solution requires a large sun exclusion zone, and would not protect the telescope from solar damage in the event of inadvertent sun exposure on the telescope mirror system, which has the potential to significantly damage the telescope.

Another approach is to decouple the sun mitigation from the telescope and construct a shading mechanism, referred to as a parasol, that serves as a physical barrier between the sun and the telescope. While this solution decreases the sun exclusion angle and protects the system in cases of inadvertent sun exposure, it is more complex and more costly than the baffle.

To compare these two sun mitigation options, a series of tests were conducted on a commercial small-scale telescope with a similar open truss design to AEOS in order to determine which solution best lowered sky background and best improved daylight imagery. Images were collected under identical conditions with the telescope in three configurations; telescope with no sun mitigation, telescope with a baffle, and telescope without the baffle but shading the telescope from direct sunlight with a disk referred to as a parasol. The parasol showed the most significant improvement.


    Develop World Class Telescope on Mount Haleakala, Maui, Hawaii
    Largest USAF optical Space Tracking Facility



    3.67-meter thin meniscus primary mirror
    Satellite tracking (17 degees/minute)
    Replaceable secondary mirror for alternative applications
    Field of View is 1 milliradian on telescope, 300 micro radian in coude' labs

    Support Facility

    Security segregation for shared use
    16-meter pier for turbulent boundary layer control
    Pier sized to support 8-meter telescope growth capability
    Seven coude' labs
    Thermal management is key design objective:
    -Extensive insulation
    -Minimize thermal pollution
    -Collapsible dome

    Adaptive optics

    Compensated imaging in all coude' labs
    -l0 centimeter resolution for 400 kilometer satellite

    Mount Control

    Minimal manning,
    Cooperative with Maui Space Surveillance Site


    Space surveillance contributing sensor --
    -Supports United States Space Command's
    -Space object Identification Statement of Need, 14-89I

    Atmospheric science -- military and environmental missions
    Astronomy -- University of Hawaii, Institute for Astronomy


    First light calendar year 1996


    Telescope & Mount Contraves USA
    Facility To be determined
    Adaptive optics To be determined,RFP--Dec 93
    Controls In-house effort
    Systems Engineering S Systems Corporation
    Maui Space Surveillance
    Site Integration Rockwell Power Systems

    Lasers & Imaging Directorate
    Air Force Phillips Laboratory
    Kirtland Air Force Base, New Mexico


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