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NASA NTRS2005

SIM-Planetquest Mission : overview and current status

This paper provides a broad overview of the SIM-PlanetQuest Mission, covering: history, science objectives, key top level requirements, how the mission will be implemented (technical and programmatic), technology development status, an assessment of where the project is today, and prognosis for the future. SIM-PlanetQuest supports the U.S. President's Vision for Space Exploration and is supported by the U.S. National Academy of Sciences.

interferometer↗
NASA NTRS2006

Precision Astrometry with SIM PlanetQuest: Science and Mission Update

This viewgraph presentation gives a science and mission update of precision Astrometry with the Space Interferometry Mission (SIM) PlanetQuest. The topics include: 1) SIM PlanetQuest - the World s First Long- Baseline Optical Interferometer in Space; 2) National Academy of Sciences / NRC endorses SIM PlanetQuest; 3) Astrometry with an Interferometer; 4) Overall Configuration (deployed); 5) SIM Planet Finding Capabilities; 6) Planet detection with SIM - minimum masses; 7) Searching for Terrestrial Planets with SIM; 8) Planets around Young Stars; 9) SIM PlanetQuest Science Team; 10) SIM Astrophysics; 11) SIM's Reach Extends Across our Entire Galaxy to do Precision Astrophysics; 12) Dynamics of Galaxy Groups within 5 Mpc; 13) Galactic tidal tails; 14) Dark Halo of our Galaxy; 15) Probing Active Galactic Nuclei with Astrometry; 16) Sample tile for relative astrometry; 17) Astrometric signatures of AGN; 18) Snapshot Observing Mode: Astrometry for the masses; and 19) SIM Technology Development is Complete.

space interferometry mission (SIM)↗
NASA NTRS2010

SIM Lite Astrometric Observatory Progress Report

The SIM Lite Astrometric Observatory (aka SIM Lite), a micro-arcsecond astrometry space mission, has been developed in response to NASA's indefinite deferral of the SIM PlanetQuest mission. The SIM Lite mission, while significantly more affordable than the SIM PlanetQuest mission concept, still addresses the full breadth of SIM science envisioned by two previous National Research Council (NRC) Astrophysics Decadal Surveys at the most stringent 'Goal' level of astrometric measurement performance envisioned in those surveys. Over the past two years, the project has completed the conceptual design of the SIM Lite mission using only the completed SIM technology; published a 250 page book describing the science and mission design (available at the SIM website: http://sim.jpl.nasa.gov); been subject to an independent cost and technical readiness assessment by the Aerospace Corporation; and submitted a number of information responses to the NRC Astro2010 Decadal Survey. The project also conducted an exoplanet-finding capability double blind study that clearly demonstrated the ability of the mission to survey 60 to 100 nearby sun-like dwarf stars for terrestrial, habitable zone planets in complex planetary systems. Additionally, the project has continued Engineering Risk Reduction activities by building brassboard (form, fit and function to flight) version of key instrument elements and subjecting them to flight qualification environmental and performance testing. This paper summarizes the progress over the last two years and the current state of the SIM Lite project.

exoplanet↗
NASA NTRS2006

SIM PlanetQuest: The TOM-3 (Thermo-Optical-Mechanical) Siderostat Mirror Test

This slide presentation reviews the Space Interferometry Mission (SIM) PlanetQuest mission. It describes the mission, shows diagrams of the instrument, the collector bays, the Siderostat mirrors, the COL bay thermal environment, the TOM-3 replicating COL Bay Environment, the thermal hardware for the SID heater control, and the results of the test are shown

Space Interferometry Mission (SIM)↗
NASA NTRS2006

Astrometeric Science with SIM PlanetQuest

This viewgraph presentation reviews Astrometry with the Space Interferometry Mission (SIM) PlanetQuest. The topics include: 1) SIM PlanetQuest - the World's First Long- Baseline Optical Interferometer in Space; 2) National Academy of Sciences / NRC endorses SIM PlanetQuest; 3) SIM Planet Search; 4) Planetary System Architectures & Diversity; 5) SIM Search for 1~10 M(sub Earth) Planets Around Nearby Stars; 6) Deep Search of 120 nearby stars; 7) Planets around Young Stars; 8) SIM PlanetQuest Science Team; 9) Dark Halo of our Galaxy; 10) Dynamics of Galaxy Groups within 5 Mpc; 11) Probing Active Galactic Nuclei with Astrometry; 12) Snapshot Observing Mode: Astrometry for the masses; 13) SIM Technology Development is Complete; and 14) SIM Hardware, Tested for Flight.

space interferometry mission (SIM)↗
NASA NTRS2006

Development and Validation of High Precision Thermal, Mechanical, and Optical Models for the Space Interferometry Mission

SIM Planetquest (SIM) is a large optical interferometer for making microarcsecond measurements of the positions of stars, and to detect Earth-sized planets around nearby stars. To achieve this precision, SIM requires stability of optical components to tens of picometers per hour. The combination of SIM s large size (9 meter baseline) and the high stability requirement makes it difficult and costly to measure all aspects of system performance on the ground. To reduce risks, costs and to allow for a design with fewer intermediate testing stages, the SIM project is developing an integrated thermal, mechanical and optical modeling process that will allow predictions of the system performance to be made at the required high precision. This modeling process uses commercial, off-the-shelf tools and has been validated against experimental results at the precision of the SIM performance requirements. This paper presents the description of the model development, some of the models, and their validation in the Thermo-Opto-Mechanical (TOM3) testbed which includes full scale brassboard optical components and the metrology to test them at the SIM performance requirement levels.

astronomy↗
NASA NTRS2006

SIM PlanetQuest: Mili-Kelvin Analysis of the Collector Sub-system Thermal Model

Space Interferometry Mission (SIM) PlanetQuest is part of the NASA Astronomical Search for Origins (ASO) program. It will use a Michelson Interferometer to locate extrasolar planets, among other objectives. The spacecraft's subsystems, temperature requirements, and thermal control approach are discussed. The current SIM thermal design is analyzed using a Milli-Kelvin approach and appears to meet temperature stability requirements on the OOPCC optic. SIM absolute temperature requirements are met through the robustness of the thermal design (i.e., PIC control).

PlanetQuest↗
NASA NTRS2008

Taking the Measure of the Universe : Precision Astrometry with SIM PlanetQuest

Precision astrometry at microarcsecond accuracy has application to a wide range of astrophysical problems. This paper is a study of the science questions that can be addressed using an instrument with flexible scheduling that delivers parallaxes at about 4 microarcsec (microns)as) on targets as faint as V = 20, and differential accuracy of 0.6 (microns)as on bright targets. The science topics are drawn primarily from the Team Key Projects, selected in 2000, for the Space Interferometry Mission PlanetQuest (SIM PlanetQuest). We use the capabilities of this mission to illustrate the importance of the next level of astrometric precision in modern astrophysics. SIM PlanetQuest is currently in the detailed design phase, having completed in 2005 all of the enabling technologies needed for the flight instrument. It will be the first space-based long baseline Michelson interferometer designed for precision astrometry. SIM will contribute strongly to many astronomical fields including stellar and galactic astrophysics, planetary systems around nearby stars, and the study of quasar and AGN nuclei. Using differential astrometry SIM will search for planets with masses as small as an Earth orbiting in the 'habitable zone' around the nearest stars, and could discover many dozen if Earth-like planets are common. It will characterize the multiple-planet systems that are now known to exist, and it will be able to search for terrestrial planets around all of the candidate target stars in the Terrestrial Planet Finder and Darwin mission lists. It will be capable of detecting planets around young stars, thereby providing insights into how planetary systems are born and how they evolve with time. Precision astrometry allows the measurement of accurate dynamical masses for stars in binary systems. SIM will observe significant numbers of very high- and low-mass stars, providing stellar masses to 1%, the accuracy needed to challenge physical models. Using precision proper motion measurements, SIM will probe the Galactic mass distribution, and through studies of tidal tails, the formation and evolution of the Galactic halo. SIM will contribute to cosmology through improved accuracy of the Hubble Constant. With repeated astrometric measurements of the nuclei of active galaxies, SIM will probe the dynamics of accretion disks around supermassive black holes, and the relativistic jets that emerge from them.

Quasars and Active Galactic Nuclei↗
NASA NTRS2005

VERSE - Virtual Equivalent Real-time Simulation

Distributed real-time simulations provide important timing validation and hardware in the- loop results for the spacecraft flight software development cycle. Occasionally, the need for higher fidelity modeling and more comprehensive debugging capabilities - combined with a limited amount of computational resources - calls for a non real-time simulation environment that mimics the real-time environment. By creating a non real-time environment that accommodates simulations and flight software designed for a multi-CPU real-time system, we can save development time, cut mission costs, and reduce the likelihood of errors. This paper presents such a solution: Virtual Equivalent Real-time Simulation Environment (VERSE). VERSE turns the real-time operating system RTAI (Real-time Application Interface) into an event driven simulator that runs in virtual real time. Designed to keep the original RTAI architecture as intact as possible, and therefore inheriting RTAI's many capabilities, VERSE was implemented with remarkably little change to the RTAI source code. This small footprint together with use of the same API allows users to easily run the same application in both real-time and virtual time environments. VERSE has been used to build a workstation testbed for NASA's Space Interferometry Mission (SIM PlanetQuest) instrument flight software. With its flexible simulation controls and inexpensive setup and replication costs, VERSE will become an invaluable tool in future mission development.

virtual real time↗
NASA NTRS2007

Quasar Astrophysics with the Space Interferometry Mission

Optical astrometry of quasars and active galaxies can provide key information on the spatial distribution and variability of emission in compact nuclei. The Space Interferometry Mission (SIM PlanetQuest) will have the sensitivity to measure a significant number of quasar positions at the microarcsecond level. SIM will be very sensitive to astrometric shifts for objects as faint as V = 19. A variety of AGN phenomena are expected to be visible to SIM on these scales, including time and spectral dependence in position offsets between accretion disk and jet emission. These represent unique data on the spatial distribution and time dependence of quasar emission. It will also probe the use of quasar nuclei as fundamental astrometric references. Comparisons between the time-dependent optical photocenter position and VLBI radio images will provide further insight into the jet emission mechanism. Observations will be tailored to each specific target and science question. SIM will be able to distinguish spatially between jet and accretion disk emission; and it can observe the cores of galaxies potentially harboring binary supermassive black holes resulting from mergers.

instrumentation↗
NASA NTRS2004

SIM PlanetQuest: Science with the Space Interferometry Mission

SIM - the Space Interferometry Mission - will perform precision optical astrometry on objects as faint as R magnitude 20. It will be the first space-based astrometric interferometer, operating in the optical band with a 10-m baseline. The Project is managed by the Jet Propulsion Laboratory, California Institute of Technology, in close collaboration with two industry partners, Lockheed Martin Missiles and Space, and TRW Inc., Space and Electronics Group. Launch of SIM is currently planned for 2009. In its wide-angle astrometric mode, SIM will yield 4 microarcsecond absolute position and parallax measurements. Astrometric planet searches will be done in a narrow-angle mode, with an accuracy of 4 microarcseconds or better in a single measurement. As a pointed rather than a survey instrument, SIM will maintain.its astrometric accuracy down to the faintest, magnitudes, opening up the opportunity for astrometry of active galactic nuclei to better than 10 pas. SIM will define a new astrometric reference frame, using a grid of approximately 1500 stars with positions accurate to 4 microarcseconds. The SIM Science Team comprises the Principal Investigators of ten Key Projects, and five Mission Scientists contributing their expertise to specific areas of the mission. Their science programs cover a wide range of topics in Galactic and extragalactic astronomy. They include: searches for low-mass planets - including analogs to our own solar system - tlie formation and dynamics of our Galaxy, calibration of the cosmic distance scale, and fundamental stellar astrophysics. All of the science observing on SIM is competitively awarded; the Science Team programs total about 40% of the total available, and the remainder will be assigned via future NASA competitions. This report is a compilation of science summaries by members of the Science Team, and it illustrates the wealth of scientific problems that microarcsecond-precision astrometry can contribute to. More information on SIM, including copies of this report, may be obtained from the project web site, at http://sim. jpl.nasa.gov.

Unwin, Stephen↗
NASA NTRS2006

SIM-PlanetQuest: Progress Report

SIM-PlanetQuest is a NASA astrophysics mission that is implementing the National Research Counsel's recommended Astrometric Interferometry Mission (AIM) to develop the first, in-space, optical, long-baseline Michelson Stellar Interferometer for performing micro-arcsecond-level astrometry. This level of astrometric precision will enable characterization of planetary systems around nearby stars and enable a number of key investigations in astrophysics including calibration of the cosmological distance scale, stellar and galactic structure and evolution, and dark matter/energy distribution. This paper provides an update on the SIM-PlanetQuest Mission covering the results of the 2005 mission redesign and the recent completion of the last in a series of technology "gates." The SIM-PlanetQuest mission redesign was directed by NASA to recover eroded mass and power margins and to meet specific implementation cost targets. The resulting mission redesign met all redesign objectives with minimal impact to mission science performance. This paper provides the mission redesign objectives and describes the resulting mission and system design including changes in science capability. SIM-PlanetQuest also completed the last of eight major technology development gates that were established in 2001 by NASA, completing the enabling technology development. The technology development program, the last gate, and its significance to the project's flight verification and validation (V&V) approach are briefly described (covered in more detail in a separate paper at this conference). An update on project programmatic status and plans is also provided.

astrometry↗
NASA NTRS2007

SIM Planetquest Science and Technology: A Status Report

Optical interferometry will open new vistas for astronomy over the next decade. The Space Interferometry Mission (SIM-PlanetQuest), operating unfettered by the Earth's atmosphere, will offer unprecedented astrometric precision that promises the discovery of Earth-analog extra-solar planets as well as a wealth of important astrophysics. Results from SIM will permit the determination of stellar masses to accuracies of 2% or better for objects ranging from brown dwarfs through main sequence stars to evolved white dwarfs, neutron stars, and black holes. Studies of star clusters will yield age determinations and internal dynamics. Microlensing measurements will present the mass spectrum of the Milky Way internal to the Sun while proper motion surveys will show the Sun's orbital radius and speed. Studies of the Galaxy's halo component and companion dwarf galaxies permit the determination of the Milky Way's mass distribution, including its Dark Matter component and the mass distribution and Dark Matter component of the Local Group. Cosmology benefits from precision (1-2%) determination of distances to Cepheid and RR Lyrae standard candles. The emission mechanism of supermassive black holes will be investigated. Finally, radio and optical celestial reference frames will be tied together by an improvement of two orders of magnitude. Optical interferometers present severe technological challenges. The Jet Propulsion Laboratory, with the support of Lockheed Martin Advanced Technology Center (LM ATC) and Northrop Grumman Space Technology (NGST), has addressed these challenges with a technology development program that is now complete. The requirements for SIM have been satisfied, based on outside peer review, using a series of laboratory tests and appropriate computer simulations: laser metrology systems perform with 10 picometer precision; mechanical vibrations have been controlled to nanometers, demonstrating orders of magnitude disturbance rejection; and knowledge of component positions throughout the whole test assembly has been demonstrated to the required picometer level. Technology transfer to the SIM flight team is now well along.

astrometry↗
NASA NTRS2008

Precision Linear Actuator for Space Interferometry Mission (SIM) Siderostat Pointing

'SIM PlanetQuest will exploit the classical measuring tool of astrometry (interferometry) with unprecedented precision to make dramatic advances in many areas of astronomy and astrophysics'(1). In order to obtain interferometric data two large steerable mirrors, or Siderostats, are used to direct starlight into the interferometer. A gimbaled mechanism actuated by linear actuators is chosen to meet the unprecedented pointing and angle tracking requirements of SIM. A group of JPL engineers designed, built, and tested a linear ballscrew actuator capable of performing submicron incremental steps for 10 years of continuous operation. Precise, zero backlash, closed loop pointing control requirements, lead the team to implement a ballscrew actuator with a direct drive DC motor and a precision piezo brake. Motor control commutation using feedback from a precision linear encoder on the ballscrew output produced an unexpected incremental step size of 20 nm over a range of 120 mm, yielding a dynamic range of 6,000,000:1. The results prove linear nanometer positioning requires no gears, levers, or hydraulic converters. Along the way many lessons have been learned and will subsequently be shared.

Cook, Brant↗
NASA NTRS2008

Precision linear actuator for Space Interferometry Mission (SIM) Siderostat pointing

“SIM PlanetQuest will exploit the classical measuring tool of astrometry (interferometry) with unprecedented precision to make dramatic advances in many areas of astronomy and astrophysics.” (1) In order to obtain interferometric data two large steerable mirrors, or Siderostats, are used to direct starlight into the interferometer. A gimbaled mechanism actuated by linear actuators is chosen to meet the unprecedented pointing and angle tracking requirements of SIM.

Moore, Don↗
NASA NTRS2008

SIM PlanetQuest: Progress Report

SIM PlanetQuest, a micro-arcsecond astrometry space mission, has been impacted by significant changes in NASA priorities over the last two years, resulting in the mission being indefinitely delayed. The SIM team has responded by investigating alternative mission concepts based upon completed SIM technology. Several alternative mission concepts have been identified, ranging from a planets-only concept, to versions of SIM, called SIM-Lite, that still address the full breadth of SIM science envisioned by two previous National Academy Astrophysics Decadal Surveys but with lower precision and reduced throughput. These mission concepts, Planet Hunter and SIM-Lite, are significantly more affordable and may fit into a nearer-term future scenario than the full SIM PlanetQuest would. This paper describes the current state of the SIM project, including its design and technology, and the alternative mission concepts for the use of these designs and technology.

SIM-Lite↗
NASA NTRS2005

Accuracy and stability of fringe measurements in SIM

In order to identify habitable planets beyond our solar system it is necessary to determine their masses. SIM PlanetQuest is the only space mission which can discover and measure planets as small and cool as those in our solar system. This mission, however, requires unprecedented accuracy of angular rneasurements to the level of a microarcsecond, which are three orders of magnitude better than accuracy of the recent space astrometric missions. For microarcsecond accuracy of astrometric measurements the corresponding fringe delay must be determined to the accuracy of picometers, and it is a challenging task to measure fringe delays to this level of precision.

interferometer↗
NASA NTRS2007

The SIM PlanetQuest Science Program

SIM PlanetQuest (hereafter, just SIM) is a NASA mission to measure the angular positions of stars with unprecedented accuracy. We outline the main astrophysical science programs planned for SIM, and related opportunities for community participation. We focus especially on SIM's ability to detect exoplanets as small as the Earth around nearby stars. The planned synergy between SIM and other planet-finding missions including Kepler and GAIA, and planet-characterizing missions including the James Webb Space Telescope (JWST), Terrestrial Planet Finder--Coronagraph (TPF-C), and Terrestrial Planet Finder--Interferometer (TPF-I), is a key element in NASA's Navigator Program to find Earth-like planets, determine their habitability, and search for signs of life in the universe. SIM's technology development is now complete and the project is proceeding towards a launch in the next decade.

SIM PlanetQuest (SIM)↗