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The Space Interferometry Mission
In this paper we will present selected topics from the SIM science program focusing on some specific astronomical questions to be addressed.
Space Interferometry Mission: Measuring the Universe
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On Multidisciplinary Modeling of the Space Interferometry Mission
This paper provides an overview of the multidisciplinary integrated modeling methodology for SIM that encompasses the optics, structures, dynamics and control disciplines within a common software environment.
High-precision early mission narrow angle sciene with the Space Interferometry Mission
We have developed a technique that allows SIM to measure relative stellar positions with an accuracy of 1 micro-arcsecond at any time during its 5-yr mission. Unlike SIM's standard narrow-angle approach, Gridless Narrow Angle Astrometry (GNAA) does not rely on the global reference frame of grid stars that reaches full accuracy after 5 years. GNAA is simply the application of traditional single-telescope narrow angle techniques to SIM's narrow angle optical path delay measurements. In GNAA, a set of reference stars and a target star are observed at several baseline orientations. A linearized model uses delay measurements to solve for star positions and baseline orientations. A conformal transformation maps observations at different epochs to a common reference frame. The technique works on short period signals (P=days to months), allowing it to be applied to many of the known extra-solar planets, intriguing radio/X- ray binaries, and other periodic sources. The technique's accuracy is limited in the long-term by false acceleration due to a combination of reference star and target star proper motion. The science capability 1 micro-arcsecond astrometric precision - is unique to SIM.
The Practice of Astrometry in Space with the Space Interferometry Mission Instrument
A short tutorial covering the basics of astrometry and interferometry relating to the SIM mission is presented.
SCDU Testbed Automated In-Situ Alignment, Data Acquisition and Analysis
In the course of fulfilling its mandate, the Spectral Calibration Development Unit (SCDU) testbed for SIM-Lite produces copious amounts of raw data. To effectively spend time attempting to understand the science driving the data, the team devised computerized automations to limit the time spent bringing the testbed to a healthy state and commanding it, and instead focus on analyzing the processed results. We developed a multi-layered scripting language that emphasized the scientific experiments we conducted, which drastically shortened our experiment scripts, improved their readability, and all-but-eliminated testbed operator errors. In addition to scientific experiment functions, we also developed a set of automated alignments that bring the testbed up to a well-aligned state with little more than the push of a button. These scripts were written in the scripting language, and in Matlab via an interface library, allowing all members of the team to augment the existing scripting language with complex analysis scripts. To keep track of these results, we created an easily-parseable state log in which we logged both the state of the testbed and relevant metadata. Finally, we designed a distributed processing system that allowed us to farm lengthy analyses to a collection of client computers which reported their results in a central log. Since these logs were parseable, we wrote query scripts that gave us an effortless way to compare results collected under different conditions. This paper serves as a case-study, detailing the motivating requirements for the decisions we made and explaining the implementation process.
The Influence of Massive Companions on the SIM\\Celestial Reference
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Results from the TOM3 testbed: thermal deformation of optics at the picometer Level
We have discussed the TOM3 testbed developed to assess the thermo-opto-mechanical stability of optical assembly such as SIM's siderostat and telescope in flight-like thermal conditions. Although limited by the metrology sensor noise, test results show that optical wavefront stability of SIM's optical assembly is compatible with single micro-arcsecond astrometry.
Space Interferometry Mission Microarcsecond Precision Astrometry
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Analytical modeling of the white light fringe
We developed technique for extracting the phase, visibility and amplitude information as needed for interferometric astrometry with the Space Interferometry Mission.
The Space Interferometry Mission
In this paper we outline the design of the SIM Instrument, and how it will be used in the search for extrasolar planets. We also briefly describe some selected topics from the SIM astrometric science program.
SIM System Testbed III
The System Testbed III (STB-3) is the flagship testbed in JPL's Interferometry Technology Program for the Space Interferometry Mission, in which it holds a place as the piece of ground hardware that looks and acts most like the real SIM space system.
SIM: An end-to-end simulation of the Space Interferometer Mission
We present the basic elements and first results of an end-to-end simulation package whose purpose is to test the validity of the Space Interferometer Mission design. The fundamental simulation time step is one millisecond, with substructure at 118 ms, and the total duration of the simulation is five years. The end product of a given wide-angle astrometry run is an estimated grid star catalog over the entire sky with an accuracy of about 4 micro-arcseconds.
Science Goals for The Space Interferometry Mission
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Description of a proposed on-orbit calibration procedure for SIM based on spacecraft maneuver
The astrometric performance of the Space Interferometry Mission relies on precise measurements of the optical pathlength difference of the starlight through the arms of the interferometers that comprise the SIM instrument, and on precise relative distance between a set of fiducials that define the baselines of the interferometers.