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1. Mission Objectives. Survive launch into space Obtain a 525 km orbit, 27 degree inclination Successfully deploy boom Telescope for X-Ray imaging Locate black holes, collapsed stars Measure distribution of material in remnant of stars Control attitude and orbit Point accurately at stars
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1. Mission Objectives • Survive launch into space • Obtain a 525 km orbit, 27 degree inclination • Successfully deploy boom • Telescope for X-Ray imaging • Locate black holes, collapsed stars • Measure distribution of material in remnant of stars • Control attitude and orbit • Point accurately at stars • Collect and transmit data back to earth • Store a certain amount of image data • Transmit at a certain rate during daily downlink • Lifetime of 24 months 1
2. Instrument Requirements • Sensitivity <2 x 10-14 erg/cm2/s (10-30 keV) <6 x 10-14 erg/cm2/s (60-75 keV) Obs. Time: 106 seconds, photon spectral index =1.7, 3 • Bandpass 10-75 keV • Spectral resolution <1.5 keV FWHM (@68 keV) • Angular resolution (HPD) <60 arcsec • Source positioning accuracy <10 arcsec 3 per axis • Field of view >8’ 2
3. Requirements Structural • Characterize thermal/structural properties of boom • Boom deflection must be within X amount • Boom deployment reliable to certain accuracy • Temperature must be kept within certain range Dynamics • Characterize dynamic responses of boom • Pointed 1 arcsec for 1 hour at operating conditions Metrology • System design accurately measure optic placement • Accurately measure detector placement w.r.t. optic 3
4. Requirements for Each Team Structural • Characterize 0-G and 1-G behavior • FEM model of structure • FD/FEM model of thermal • Mass properties • Error budget Dynamics • Dynamical model • Environmental disturbances (external, internal) • Dynamical responses (frequency) • Sensitivity studies • Error budget Metrology • Choose measurement system • Laser v.s. particle velocimetry • Error budget 4
Structural TeamElah Bozorg-Grayeli Francisco Chacon Vahe Gabuchian Ajay HarishAlireza Karim Zac Lizer Elliott PallettMatthew Wierman 5
Receivables and Deliverables • Receivables from other teams • Dynamics Team: Vibration sources for modal analysis. • Metrology Team: Accuracies necessary for equipment. Can we rotate for thermal management • Receivables from JPL • Mission conditions • Pointing conditions • Launch requirements • Deploying procedure • Deliverables • Dynamics • FEM Model: Modal analysis results (mass, stiffness, damping) • Mass properties • Metrology • FEM Model: Modal analysis results (stability) • Error Budget • Thermal • Deflections • 0-g and 1-g FEM Model 6
Team Objectives and Steps Outlined • TEAM OBJECTIVES • Characterize 0 and 1-g behavior of S/C • FEM of structure • FD/FEM of structure • Mass properties • Error budget and sensitivity studies • Integrate structural and thermal models of system • STEPS OUTLINED • Build FEM model from configuration • Run FEM model for 0-g body force and 1-g body force conditions • Compare 1-g data with experimental data • Integrate FEM and thermal model • Modal analysis • Determine thermal loads on system • Conduct material analysis of structure • Determine possible configuration changes 7
Dynamics TeamPrakhar MehrotraInki ChoiKevin WattsAjay HarishDerek ChanSilas Hilliard 8
Receivables and Deliverables • Receivables from other teams • Structural Team: M, K, C for dynamics model • Metrology Team: Accuracies & tolerances; Sensor inputs that relates to observability • Receivables from JPL • Decide how to model disturbance forces • Internal (Reaction wheels) • External (Solar pressure, Drag etc) • More details on S/C configuration • Reaction wheel, Torqrod configuration and specs • Mass model comes from Structure team • Deliverables • Complete dynamic model and modal analysis • Orbital information and effect of disturbance forces • Dynamic responses in time/frequency domain • Controllability and observability of S/C • Sensitivity studies and error budget • Develop framework for determining optimal control 9
Team Objectives and Steps Outlined • TEAM OBJECTIVES • Dynamic modeling (before PDR) • Orbital dynamics (before PDR) • Altitude control (after PDR) • Stability of spacecraft about each axis – x, y and z • Error budget and sensitivity studies • Create framework to design optimal control system • STEPS OUTLINED • Obtain dynamic model • Determine orbital motion • Point mass Rigid body Flexible body • Determine attitude dynamics, controllability and observability • Dynamic analysis in time/frequency domain • Control system plan • System block diagrams 10