The Mount Stromlo LGS facility includes two laser systems: a fiber-based sum-frequency laser designed and built by EOS Space Systems in Australia, and a Semiconductor Guidestar Laser designed and built by Aret´e Associates in the USA under contract with the Australian National University. The Beam Transfer Optics (BTO) enable either simultaneous or separate propagation of the two lasers to create a single LGS on the sky. This paper provides an overview of the Mount Stromlo LGS facility design, integration and testing of the two sodium guidestar lasers in the laboratory and on the EOS 1.8m telescope.
Optimal transmission of pulsed laser energy to a target is essential for the maximization of reflected signal power in Debris Laser Ranging (DLR) systems. We describe the use of the PPPP measurement technique to allow compensation for both wavefront aberration, tip/tilt and errors arising from misalignment of the transmit and receive optical axes. This paper provides an update on the bistatic Wavefronts Obtained by Measuring Beam-profiles through Atmospheric Turbulence (WOMBAT) trial1 conducted with the EOS Space Systems 1.8m DLR system2 on Mt Stromlo, Australia, using an adjacent telescope to observe the 170 Hz PPPP intensity profiles.
We report on the design and initial laboratory testing of the Adaptive Optics Imaging (AOI) system. AOI has been developed by the Research School of Astronomy and Astrophysics (RSAA) at the Australian National University (ANU), in partnership with the Space Environment Research Centre (SERC), for imaging satellites and debris in low Earth orbit (LEO) and geostationary orbit (GEO). From AO corrected images we will resolve features greater than 50 cm allowing size, shape and orientation characterisation.
As space debris in lower Earth orbits are accumulating, techniques to lower the risk of space debris collisions must be developed. Within the context of the Space Environment Research Centre (SERC), the Australian National University (ANU) is developing an adaptive optics system for tracking and pushing space debris. The strategy is to pre-condition a laser launched from a 1.8 m telescope operated by Electro Optics Systems (EOS) on Mount Stromlo, Canberra and direct it at an object to perturb its orbit. Current progress towards implementing this experiment, which will ensure automated operation between the telescope and the adaptive optics system, will be presented.
The Research School of Astronomy and Astrophysics have been developing adaptive optics systems for space situational awareness. As part of this program we have developed satellite imaging using compact adaptive optics systems for small (1-2 m) telescopes such as those operated by Electro Optic Systems (EOS) from the Mount Stromlo Observatory. We have focused on making compact, simple, and high performance AO systems using modern high stroke high speed deformable mirrors and EMCCD cameras. We are able to track satellites down to magnitude 10 with a Strehl in excess of 20% in median seeing.
Space debris in Low Earth Orbit (LEO) is becoming an increasing threat to satellite and spacecraft. A reliable and cost effective method for detecting possible collisions between orbiting objects is required to prevent an exponential growth in the number of debris. Current RADAR survey technologies used to monitor the orbits of thousands of space debris objects are relied upon to manoeuvre operational satellites to prevent possible collisions. A complimentary technique, ground-based laser LIDAR (Light Detection and Ranging) have been used to track much smaller objects with higher accuracy than RADAR, giving greater prediction of possible collisions and avoiding unnecessary manoeuvring. Adaptive optics will play a key role in any ground based LIDAR tracking system as a cost effective way of utilising smaller ground stations or less powerful lasers. The use of high power and high energy lasers for the orbital modification of debris objects will also require an adaptive optic system to achieve the high photon intensity on the target required for photon momentum transfer and laser ablation. EOS Space Systems have pioneered the development of automated laser space debris tracking for objects in low Earth orbit. The Australian National University have been developing an adaptive optics system to improve this space debris tracking capability at the EOS Space Systems Mount Stromlo facility in Canberra, Australia. The system is integrated with the telescope and commissioned as an NGS AO system before moving on to LGS AO and tracking operations. A pulsed laser propagated through the telescope is used to range the target using time of flight data. Adaptive optics is used to increase the maximum range and number or targets available to the LIDAR system, by correcting the uplink laser beam. Such a system presents some unique challenges for adaptive optics: high power lasers reflecting off deformable mirrors, high slew rate tracking, and variable off-axis tracking correction. A low latency real time computer system is utilised to control the systems, with a Shack-Hartmann wavefront sensor and deformable mirror running at 1500 frames per second. A laser guide star is used to probe the atmosphere and the tracked debris object is used as a natural guide star for tip-tilt correction.
The Australian National University and EOS Space Systems have teamed up to equip the EOS laser space debris tracking station on Mount Stromlo near Canberra, Australia, with sodium Laser Guide Star (LGS) Adaptive Optics (AO). The AO system is used to correct for laser beam degradation caused by the atmospheric turbulence on the upward infrared laser pulse used to illuminate space debris. As a result, the AO-equipped laser tracking station can track smaller and more distant debris. This paper presents the joint ANU/EOS AO Demonstrator LGS facility requirements, architecture, and performance at the time of the conference.
Space debris in low Earth orbit below 1500km is becoming an increasing threat to satellites and spacecrafts.
Radar and laser tracking are currently used to monitor the orbits of thousands of space debris and active satellites
are able to use this information to manoeuvre out of the way of a predicted collision. However, many satellites
are not able to manoeuvre and debris-on debris collisions are becoming a signicant contributor to the growing
space debris population. The removal of the space debris from orbit is the preferred and more definitive solution. Space debris removal may be achieved through laser ablation, whereby a high power laser corrected with an adaptive optics system could, in theory, allow ablation of the debris surface and so impart a remote thrust on the targeted object. The goal of this is to avoid collisions between space debris to prevent an exponential increase in the number of space debris objects. We are developing an experiment to demonstrate the feasibility of laser ablation for space debris removal. This laser ablation demonstrator utilises a pulsed sodium laser to probe the atmosphere ahead of the space debris and the sun reflection of the space debris is used to provide atmospheric tip{tilt information. A deformable mirror is then shaped to correct an infrared laser beam on the uplink path to the debris. We present here the design and the expected performance of the system.
This paper describes the preliminary optomechanical design and analysis of the Gemini Adaptive Optics Bench being built by EOS Technologies, Inc. The overall optical arrangement is described, the optical tolerances are discussed, and an overview of the optomechanical packaging is provided. Emphasis is placed on integrated modeling of the optomechanical system to predict the effect of mechanical deformation on optical performance
The NASA Outrigger Telescope Project is a ground-based component of NASA's Navigator Program. The proposed project would utilize four to six 1.8-meter telescopes with co-rotating domes configured as an interferometer. One of the project’s scientific goals is the detection of exoplanets, which would be accomplished with long baseline narrow-angle astrometry. This astrometry mode would be able to detect Uranus mass planets up to 60 light years away. The requirements of narrow-angle astrometry, both technically and operationally, levy requirements on the telescopes and enclosures, including, for example, wavefront quality, pivot stability, and slew speed. This paper will describe these requirements and how they were achieved in the design. It will also discuss the testing and verification of these requirements. Actual telescope performance as tested at EOS Technologies is presented elsewhere in these proceedings.
EOS Technologies has completed four 1.8m telescopes that are to be used in the NASA/JPL Interferometer. The 1.8m telescopes (Outriggers) will form the workhorse of the interferometric system. This paper presents some of the performance data obtained during the Telescope Factory Acceptance Tests showing some of the best telescope performance ever achieved with a telescope of this class.
We present the outline and the current status of the MAGNUM automated observation system. The operational objective of the MAGNUM Project is to carry out long-term multi-color monitoring observations of active galactic nuclei in the visible and near-infrared wavelength regions. In order to obtain these observations, we built a new 2 m optical-infrared telescope, and sited it at the University of Hawaii's Haleakala Observatory on the Hawaiian Island of Maui. Preliminary observations were started early in 2001. We are working toward the final form of the MAGNUM observation system, which is an unmanned, automated observatory. This system requirement was set by considering that the observation procedures are relatively simple, and the targets must be observed consistently over many years.
We describe a multi-element refractive corrector for the prime focus of the proposed Lowell four-meter telescope. The design provides sub-half arcsecond images over a two-degree field of view, with a flat image surface and images that are confocal across a broad wavelength band covering the U to I spectral range. Initial studies cover the feasibility of fabrication and explore the possibility of a simple atmospheric dispersion corrector.
In the year 2000, EOS Technologies, Inc. of Tucson, Arizona will complete six two-meter class telescopes for astronomy. Applications for these telescopes range from monitoring of active-galactic nuclei to the search for extra-solar planets. Four of the telescopes will form part of the Keck International Project. These telescopes meet the highest tracking and axis interaction specifications ever attempted in a two-meter class telescope. Each of these telescopes is capable of fully remote-control and semi-autonomous operation.
We have built an imaging polarimeter for use at mid-IR wavelengths (i.e. N band or 8 - 13 micrometers ). The detecting element is a 128 x 128 element Si:Ga Focal Plane Array, supplied by Amber Engineering, USA. The polarimeter itself provides diffraction limited images on a 4 m class telescope and has a field of view of about 32 arcseconds of sky with 1/4 arcsecond pixels. The two orthogonal planes of polarization can be imaged simultaneously so that each integration provides an independent measure of polarization. This instrument had a successful commissioning run in July 1993, and the polarization beam splitting assembly will be commissioned in May of this year.
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