Ifan Payne

The Magdalena Ridge Observatory interferometer: first light and deployment of the first telescope on the array

The Magdalena Ridge Observatory Interferometer (MROI) has been under development for almost two decades. Initial funding for the facility started before the year 2000 under the Army and then Navy, and continues today through the Air Force Research Laboratory. With a projected total cost of substantially less than

Towards integration of the Unit Telescope for the Magdalena Ridge Observatory interferometer

200M, it represents the least expensive way to produce sub-milliarcsecond optical/near-infrared images that the astronomical community could invest in during the modern era, as compared, for instance, to extremely large telescopes or space interferometers. The MROI, when completed, will be comprised of 10 x1.4m diameter telescopes distributed on a Y-shaped array such that it will have access to spatial scales ranging from about 40 milliarcseconds down to less than 0.5 milliarcseconds. While this type of resolution is not unprecedented in the astronomical community, the ability to track fringes on and produce images of complex targets approximately 5 magnitudes fainter than is done today represents a substantial step forward. All this will be accomplished using a variety of approaches detailed in several papers from our team over the years. Together, these two factors, multiple telescopes deployed over very long-baselines coupled with fainter limiting magnitudes, will allow MROI to conduct science on a wide range and statistically meaningful samples of targets. These include pulsating and rapidly rotating stars, mass-loss via accretion and mass-transfer in interacting systems, and the highly-active environments surrounding black holes at the centers of more than 100 external galaxies. This represents a subsample of what is sure to be a tremendous and serendipitous list of science cases as we move ahead into the era of new space telescopes and synoptic surveys. Additional investigations into imaging man-made objects will be undertaken, which are of particular interest to the defense and space-industry communities as more human endeavors are moved into the space environment. In 2016 the first MROI telescope was delivered and deployed at Magdalena Ridge in the maintenance facility. Having undergone initial check-out and fitting the system with optics and a fast tip-tilt system, we eagerly anticipate installing the telescope enclosure in 2018. The telescope and enclosure will be integrated at the facility and moved to the center of the interferometric array by late summer of 2018 with a demonstration of the performance of an entire beamline from telescope to beam combiner table shortly thereafter. At this point, deploying two more telescopes and demonstrating fringe-tracking, bootstrapping and limiting magnitudes for the facility will prove the full promise of MROI. A complete status update of all subsystems follows in the paper, as well as discussions of potential collaborative initiatives.

A new path to first light for the Magdalena Ridge Observatory interferometer

The Unit Telescope (UT) for the Magdalena Ridge Observatory (MROI) is composed of four major hardware components: The Unit Telescope Mount (UTM), Enclosure, Optics and the Fast Tip Tilt System (FTTS). Integration of the UT started in 2016 when the UTM arrived and its Assembly, Integration and Verification activities began. Critical activities included: installation at the Maintenance Facility, integration and alignment of the Optics and Wave Front Sensor (WFS) and finally the complete optical alignment. End-to-end UTM Site Acceptance Tests (SAT) were performed. Subsequent activities included receiving and integrating the FTTS. With the arrival and assembly of the Enclosure, the last component of the UT was ready for integration on a dedicated concrete pier. Specialized equipment will be used for the final integration of the UT, and for transportation to its final location on the array where SAT for the UT will take place.

Numerical simulations of MROI imaging of GEO satellites

The Magdalena Ridge Observatory Interferometer (MROI) was the most ambitious infrared interferometric facility conceived of in 2003 when funding began. Today, despite having suffered some financial short-falls, it is still one of the most ambitious interferometric imaging facilities ever designed. With an innovative approach to attaining the original goal of fringe tracking to H = 14th magnitude via completely redesigned mobile telescopes, and a unique approach to the beam train and delay lines, the MROI will be able to image faint and complex objects with milliarcsecond resolutions for a fraction of the cost of giant telescopes or space-based facilities. The design goals of MROI have been optimized for studying stellar astrophysical processes such as mass loss and mass transfer, the formation and evolution of YSOs and their disks, and the environs of nearby AGN. The global needs for Space Situational Awareness (SSA) have moved to the forefront in many communities as Space becomes a more integral part of a national security portfolio. These needs drive imaging capabilities ultimately to a few tens of centimeter resolution at geosynchronous orbits. Any array capable of producing images on faint and complex geosynchronous objects in just a few hours will be outstanding not only as an astrophysical tool, but also for these types of SSA missions. With the recent infusion of new funding from the Air Force Research Lab (AFRL) in Albuquerque, NM, MROI will be able to attain first light, first fringes, and demonstrate bootstrapping with three telescopes by 2020. MROI’s current status along with a sketch of our activities over the coming 5 years will be presented, as well as clear opportunities to collaborate on various aspects of the facility as it comes online. Further funding is actively being sought to accelerate the capability of the array for interferometric imaging on a short time-scale so as to achieve the original goals of this ambitious facility

The MROI's capabilities for imaging geosynchronous satellites

All of the design work and major construction has been completed for the Magdalena Ridge Observatory interferometer (MROI). The majority of the subsystems are currently (2012) being assembled. When completed, the array will consist of 10 fully transportable 1.4 m telescopes. These will support multiple array configurations, with baselines from 7.8 m to 346 m to give sub-milliarcsecond angular resolution. We provide an assessment of the potential imaging capability of the MRO interferometer with regard to geosynchronous targets. Our preliminary results suggest that a significant proportion of GEO targets may be accessible and that it may be possible to routinely extract key satellite diagnostics with an imaging capability that would be able to distinguish, for example, 70 cm features on a 5-meter satellite bus and payload, 30 cm features on a 2-meter satellite bus or similarly sized structure, as well as precise quantitative information on much larger structures such as 10 m long solar panels. Optimised observation and data reduction strategies are likely to allow these limits to be improved in due course.

Aperture synthesis imaging of colored GEO objects

Interferometry provides the only practicable way to image meter-scale structure in geosynchronous satellites. This capability represents a unique commercial opportunity for astronomical interferometry, but to date no interferometer has been able to make an image of such a satellite. We discuss the challenges of imaging these objects and present results of sensitivity calculations and imaging simulations which show that the Magdalena Ridge Observatory Interferometer is likely to be well-suited to this application. Our preliminary results suggest that a significant proportion of GEO targets may be accessible and that it may be possible to routinely extract key satellite diagnostics with an imaging capability that would be able to distinguish, for example, 70 cm features on a 5-meter satellite bus and payload, 30 cm features on a 2-meter satellite bus or similarly sized structure, as well as precise quantitative information on much larger structures such as 10 m long solar panels. Optimised observation and data reduction strategies are likely to allow these limits to be improved in due course.

MROI unit telescope enclosure manufacturing and tests

Interferometry provides the only practicable way to image satellites in Geosynchronous Earth Orbit (GEO) with sub-meter resolution. The Magdalena Ridge Observatory Interferometer (MROI) is being funded by the US Air Force Research Laboratory to deploy the central three unit telescopes in order to demonstrate the sensitivity and baseline-bootstrapping capability needed to observe GEO targets. In parallel, we are investigating the resolution and imaging fidelity that is achievable with larger numbers of telescopes. We present imaging simulations with 7- and 10- telescope deployments of the MROI, and characterize the impact of realistic spectral variations compared with a “gray” satellite.

MROI Array telescopes: the relocatable enclosure domes

The MROI – Magdalena Ridge Observatory is a project that comprises an array of 10 1.4m diameter mirror telescopes, arranged in a “Y” configuration. Each of these telescopes will be housed inside a Unit Telescope Enclosure (UTE) that is relocatable onto any of 28 stations. EIE Group Srl, based in Venice – Italy, was awarded the contract for the design, construction and erection on site of the MROI UTE by New Mexico Institute of Mining and Technology. The close-pack array of the MROI – including all 10 telescopes, several of which are at a relative distance of less than 8 meters center to center from each other – necessitated an original design for the UTE. February 2018 saw a series of Factory Acceptance Tests to verify that everything is working in a proper way, to guarantee the restricted performances in the sky. These performances will be respected only thanks to a detailed engineering design and special materials. The first enclosure is now on-site, in order to be assembled with the telescope, before its final positioning in the array.

High fidelity imaging of geosynchronous satellites with the MROI

The MROI - Magdalena Ridge Interferometer is a project which comprises an array of up to 10 1.4m diameter mirror telescopes arranged in a “Y” configuration. Each of these telescopes will be housed inside a Unit Telescope Enclosure (UTE) which are relocatable onto any of 28 stations. EIE GROUP Srl, Venice – Italy, was awarded the contract for the design, the construction and the erection on site of the MROI by the New Mexico Institute of Mining and Technology. The close-pack array of the MROI - including all 10 telescopes, several of which are at a relative distance of less than 8m center to center from each other - necessitated an original design for the Unit Telescope Enclosure (UTE). This innovative design enclosure incorporates a unique dome/observing aperture system to be able to operate in the harsh environmental conditions encountered at an altitude of 10,460ft (3,188m). The main characteristics of this Relocatable Enclosure Dome are: a Light insulated Steel Structure with a dome made of composites materials (e.g. glass/carbon fibers, sandwich panels etc.), an aperture motorized system for observation, a series of louvers for ventilation, a series of electrical and plants installations and relevant auxiliary equipment. The first Enclosure Dome is now under construction and the completion of the mounting on site id envisaged by the end of 2016. The relocation system utilizes a modified reachstacker (a transporter used to handle freight containers) capable of maneuvering between and around the enclosures, capable of lifting the combined weight of the enclosure with the telescope (30tons), with minimal impacts due to vibrations.

Operating observatories, the need for a new paradigm

Interferometry currently provides the only practicable way to image satellites in Geosynchronous Earth Orbit (GEO) with sub-meter spatial resolution. The Magdalena Ridge Observatory Interferometer (MROI) is being funded by the US Air Force Research Laboratory to demonstrate the 9.5 magnitude sensitivity (at 2.2 μm wavelength) and baseline-bootstrapping capability that will be needed to realize a useful turn-key GEO imaging capability. This program will utilize the central three telescopes of the MROI and will aim to validate routine acquisition of fringe data on faint well-resolved targets. In parallel with this effort, the University of Cambridge are investigating the spatial resolution and imaging fidelity that can be achieved with different numbers of array elements. We present preliminary simulations of snapshot GEO satellite imaging with the MROI. Our results indicate that faithful imaging of the main satellite components can be obtained with as few as 7 unit telescopes, and that increasing the number of telescopes to 10 improves the effective spatial resolution from 0.75 meter to 0.5 meter and enables imaging of more complex targets.