Small Satellite Platform Imaging X-Ray Polarimetry Explorer (IXPE) Mission Concept and Implementation (SSC18-V-XX) 32nd Annual Small Satellite Conference, Logan, UT, USA 4-9 August 2018 7 August: 14:00 – 14:15 Presented by: Dr. William Deininger Ball Aerospace This work was authored by employees of Ball Aerospace under Contract No.NNM16581489R with the National Aeronautics and Space Administration. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, or allow others 1 to do so, for United States Government purposes. All other rights are reserved by the copyright owner. CO-AUTHORS . William Kalinowski – IXPE Spacecraft Lead and . Scott Mitchell – IXPE Mission Design Lead, Ball C&DH Lead, Ball . Sarah Schindhelm – IXPE Structural Design . Jeff Bladt – IXPE ADCS Lead, Ball Lead, Ball . Zach Allen – IXPE EPDS and Electrical Systems . Janice Houston – IXPE Lead Systems Engineer, Lead, Ball MSFC . Kyle Bygott – IXPE Spacecraft FSW Lead, Ball . Brian Ramsey – IXPE Deputy Principal . Brian Smith – IXPE AI&T Manager, Ball Investigator (DPI), MSFC . Colin Peterson – IXPE Mission Operations . Stephen O’Dell – IXPE Project Scientist, MSFC Manager, Ball . Michele Foster – IXPE V&V Engineer, MSFC . Spencer Antoniak – IXPE Launch Services, Ball . Ettore Del Monte – IXPE Instrument Systems . Jim Masciarelli – IXPE Metrology and Payload Engineering Lead, IAPS/INAF Systems Lead, Ball . Francesco Santoli – IXPE Instrument Systems . Jennifer Erickson – IXPE Requirement Lead, Ball Engineering, IAPS/INAF . Sandra Johnson – IXPE Telecommunications . Alessio Trois – IXPE Instrument FSW, INAF Lead, Ball . Michele Pinchera – IXPE Instrument . Jeff Wedmore – IXPE Mechanical Systems Mechanical/Thermal Design, INFN Design Lead, Ball . Massimo Minuti – IXPE Instrument . Tim Read – IXPE Thermal Lead, Ball Mechanical/Thermal Design, INFN . Christina Pentz – IXPE Structural Analysis Lead, . Darren Osborne – IXPE Mission Operations Ball Center, CU/LASP . Larry Guy – IXPE Mechanisms Lead, Ball . Mike McEachen – Boom/TTR, Orbital ATK . Chris Seckar – IXPE Alignment Lead, Ball 2 CONTENTS . Introduction . Overview of science . Project partners and roles . Technical summary • Observatory • Payload • Spacecraft . Milestones and Conclusions . Acknowledgements 3 IXPE SCIENTIFIC OBJECTIVES IXPE’s overarching science goal is to expand the understanding of high- energy astrophysical processes and sources in support of NASA's first scientific objective in astrophysics: “Discover how the universe works” IXPE will study targets over a broad range of types of astronomical X-ray sources with an emphasis on black holes and neutron stars • Constrain the radiation processes and detailed properties of different types of cosmic X-ray sources • Investigate general relativistic and quantum effects in extreme environments • Constrain the geometry and the emission mechanism(s) of AGN and microquasars • Establish the geometry and strength of the magnetic field in magnetars • Constrain the geometry and origin of the X-radiation from radio pulsars • Learn how particles are accelerated in Pulsar Wind Nebulae and in (shell-type) Supernova Remnants Polarimetry of X-ray sources largely unmeasured; Opens a new window on the X-ray Universe 4 IXPE SCIENCE . X-ray emission from energetic processes: In-fall of matter into Neutron Star or Black Hole, synchrotron or shock emission, or very hot regions • Can originate both from point and extended sources; Imaging separates these sources • Polarization of X-rays if occurs there is anisotropy in emission geometry or mag field, plasma reflections, or general relativistic effects Crab Pulsar Extended X-ray emission Credit: Credit: Credit: NASA NASA / ESA /SAO and STScI Imaging separates regions with Polarization probes the source different emission mechanisms geometry and mag field strength 5 IXPE IMAGING LIMITS SOURCE CONFUSION • Active Galactic Nuclei (AGN) powered by supermassive Black Holes with jets • Use X-ray polarimetric imaging to directly examine magnetic-field topology of AGN jet • Radio polarization implies the magnetic field is aligned with jet • Different models for electron acceleration predict different dependence in X-rays • IXPE can image the Cen A jet and isolate it from other sources in the field (e.g., Ultra Luminous X-ray source) LEO observatory that measures spatial, spectral, timing, and polarization state of X-rays from 48 known astrophysical targets 6 MAGNETARS - MEASUREMENT OF QUANTUM- ELECTRODYNAMIC (QED) EFFECT . Perform X-ray phase-resolved polarimetry to enable measurement of magnetic-field strength and geometry (quantum-electrodynamic (QED) effect) — “vacuum birefringence — detectable only in super- strong magnetic fields • Magnetar is a neutron star with magnetic field up to 1015 Gauss • Non-linear QED predicts magnetized-vacuum birefringence • Refractive indices of the two polarization modes differ from 1 and from each other which impacts polarization and position angle as functions of pulse phase • Example is 1RXS J170849.0-400910, with an 11-s pulse period • Can exclude QED-off at better than 99.9% confidence in 250-ks observation 7 WHO’S MAKING THE MISSION HAPPEN? TEAM IXPE: PARTNERSHIPS & RELATIONSHIPS Italian Space Agency (ASI) NASA Science Mission Directorate Rome, Italy Astrophysics Division Washington D.C. Explorers Program Office Ground Station ASI Goddard Space Flight Center (GSFC) Malindi, Kenya Greenbelt, MD Launch Services Program Kennedy Space Center Cape Canaveral, FL IXPE Project Office Italian Project Manager Marshall Space Flight Center (MSFC) Rome, Italy Huntsville, AL Instrument DU Project DSU, EGSE X-ray Optics Spacecraft/Observatory Integration Ground Station Project Office Office Project Office MSFC Ball Aerospace KSAT Singapore INAF INFN OHB-I Huntsville, AL Boulder, CO Rome Turin Milan Thermal Shields Mission Operations Implementing Arrangements Laboratory for Atmospheric & Space Physics (LASP) Nagoya Boulder, CO Contractual Relationships University Nagoya Japan Science Operations IXPE Telescope MSFC Huntsville, AL 8 IXPE HAS A STRAIGHT FORWARD MISSION CONCEPT . NASA Small Explorer (SMEX) Mission • Class D Mission . IXPE Observatory is a single flight element . Observatory launched to a 540 km, 0° orbit . Launch vehicle is being selected . 2 year baseline mission with 1 year extended mission option . 3 deployments, all during contacts . Point and stare at known targets . Omni-directional S-band uplink/downlink . Launch April 2021 9 IXPE CONCEPT OF OPERATIONS OVERVIEW 10 IXPE OBSERVATORY – STOWED (PEGASUS XL FAIRING ENVELOP) +Z Star Tracker Pegasus XL Fairing Envelop X-Ray Shield Mirror Module MMSS Launch Locks Support Structure (MMSS) Deck Payload MMSS Bipods Mirror Module 2.2 m MMSS Center Tube Assembly (MMA) Deployable Boom Detector Unit Canister (DU) Stowed Solar Array Spacecraft Spacecraft Spacecraft Top Deck Launch Attach Fitting 11 IXPE OBSERVATORY – DEPLOYED • Solar array deploys during auto-initialization sequence, arrays sun-pointed • Boom deployment commanded while over Malindi ground station • X-ray shields deployment commanded while over Malindi ground station +Z Star Tracker Boom Deployed X-Ray Shield Deployed Solar Array IXPE Spacecraft Mirror Module Assembly (MMA) (3) Bipod (3) Detector Unit (DU) (3) 12 PAYLOAD OVERVIEW Focus X-rays using MMSS Deck Deployed X-Ray Shield Set of three mirror module assemblies Metrology Camera (MMA) MMSS Center Tube Tip/Tilt/Rotate Onto three Deployable Boom corresponding gas pixel detector units (DU) +Z Star DU (3) Tracker Co-aligned with +Z MMA (3) tracker Metrology Launch Lock (3) Target With focal length of Bipod (3) Detectors 4.001 m established by Service Unit Spacecraft boom (DSU) Top Deck -Z DUs Radiator 13 IXPE SPACECRAFT BASED ON BCP SMALL PLATFORM STPSat-2 STPSat-3 . STPSat-2 – launched 11/2010 . STPSat-3 – launched 11/2013 . GPIM – launch now planned fall 2018 GPIM 14 IXPE SPACECRAFT Coarse Sun Transceiver Deployable Boom Star Tracker, -Z Sensors (12 total) Payload components with Thermal Sock (2) Filters shown ghosted (2) Couplers IAU Star Tracker Reaction Wheel Z Elec. Unit (3) Detector GPS Rx Torque Rod Y Units (3) MMSS Solar Array Torque Rod X Launch Locks (3) MMSS Bipods TT&C Antenna, +Y Battery GPS Antenna, +Y Metrology Target Top Deck Detectors Service Unit Reaction Wheel Y Top Deck Torque Rod Z Reaction Wheel X TT&C Antenna, -Y Not Shown: GPS Antenna, -Y +Z Star Tracker Arming Pad Magnetometer +Z CSS (4) Solar Array RRS LV PAF 15 Bus Shear Panels (6) IXPE SPACECRAFT CAPABILITIES Spacecraft Parameter Capability Orbit Altitude 540 km Orbit Inclination 0° Launch Mass ~325 kg Orbit Average Power (OAP) 300 W LV Compatibility Pegasus XL SV Lifetime 2 years, no life-limiting consumables Stabilization Method 3-axis Pointing Modes Acquire Sun State (Safe Mode), Point State (Ops Mode) Attitude Control 40 arcsec (3σ); x- & y-axis, Point State Bus Voltage 28 V ± 6 V Communication Frequency S-Band / NEN & TDRSS Compatible Command Rate 2 Kbps uplink Telemetry Rate 2 Mbps downlink On-Board Data Storage 6 GBytes Payload mass 170 kg (total) Payload Data Handling Up to 2.0 Mbps from DSU Payload Command/Data I/F RS-422, discrete I/O, analog 16 PROJECT STATUS AND KEY MILESTONES . IXPE Project Phase B Kicked off February 2017 . Mission SRR held 18,19 September 2017 . X-ray