EXPANDING THE X-RAY VIEW OF THE UNIVERSE

IMAGING X-RAY POLARIMETRY EXPLORER IXPEOpens new dimensions for exploring how X-ray emission is produced under extreme physical conditions near objects such as neutron stars and black holes

Observatory Spacecraft and Payload HardwareBoth Have High Heritage Designs: All Elements ≥TRL 6

Key Spacecraft Characteristics 3-axis, zero net momentum control 25” (3σ) pointing accuracy (110% margin) Observatory mature mass: 292kg,

>30% launch margin 257 W EOL power for 35% margin (worst case) S-band communications at 2Mbps downlink 6GB data storage (50% margin)

Detector Units(3x)

Tip Tilt Rotate (TTR) Mechanism(used once to correct boom

deployment o�set)

+Z Star Tracker

–Z Star Tracker(hidden)Green = contributed funding

Shields(3x, to minimize

X-ray background)Mirror ModuleAssembly(MMA)(3x)

Deployable Payload Boom(covered by Thermal Sock)

Deployed Solar Array

Spacecraft Bus

Mission Design andOperations Concept

Observatory Command &

Control

User Support

Observatory Science &

Housekeep-ing Data

Science Data Archiving & Distribution

Mission Planning

DataProducts

Tlm

Targets

ObservingSchedule

Cmds

• Pegasus launch from Kwajalein (RTS) on or after 11/20/2020

• 540-km circular orbit at nominal 0° inclination

• Two-year mission• Point-and-stare

observations of known targets

• Science Operations Center (SOC) at MSFC

• Mission Operations Center (MOC) at CU/LASP

• Ground Station at Malindi (backup: Singapore)

MOC SOC

Malindi(ASI contributed)

CU/LASP MSFC

IXPE

HEASARC

Science Community

Data

GSFC

CandidateTargets

IXPE Team MSFC and IXPE Science Partners

ScienceTeam

Science Data Processing

Data Analysis& Publication

Review

IXPE Maps the Magnetic Field of Bright Extended X-raySources and Reduces Source Confusion

Simulated IXPE image (left) near the center of the bright AGN Centaurus A with superposed polarization model and a contour map (right) of the expected RMS noise in measuring the degree of polarization. IXPE imaging will resolve the AGN's jet and core and two adjacent sources, enabling unambiguous polarization measurements of each component.

1-σ Error in Degree of Polarization (%)for 40“ x 40” bin size

Clear Science Requirements Drive the Payload Definition• Measurement objectives are met with three identical telescopes, each with a Mirror Module

Assembly and a polarization-sensitive imaging Detector Unit• IXPE payload features a 2-8 keV range, proportional counter energy resolution,

11´ field-of-view, and ≤30" angular resolution• Mature mirror and detector technologies were pioneered and developed by the IXPE team

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Cen A Simulated at IXPE Resolutionwith Di�use Component Subtracted

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min

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Institutional Roles & Responsibilities• MSFC – PI team, project management, SE and S&MA oversight, mirror

module fabrication, X-ray calibration, science operations, and science data processing and archiving

• Ball Aerospace – Spacecraft, payload structure, payload and observatory I&T

• ASI – Detector system funding, ground station• IAPS/INAF and INFN – Polarization-sensitive imaging detector systems• CU/LASP – Mission operations• Stanford and Univ Roma Tre – Scientific theory• McGill University – Science Working Group Co-Chair• MIT – Co-Investigator

Fundamental New Measurements Address Key Science QuestionsIXPE will improve sensitivity over OSO-8, the only previous X-ray polarimeter, by two orders of magnitude in required exposure time. IXPE also will introduce the capability for X-ray polarimetric imaging, uniquely enabling the measurement of X-ray polarization with scientifically meaningful spatial, spectral, and temporal resolution, to address NASA’s Science Mission Directorate's science goal "to probe the origin and destiny of our universe, including the nature of black holes, dark energy, dark matter, and gravity."IXPE measurements will provide new dimensions for probing a wide range of cosmic X-ray sources—including active galactic nuclei (AGN) and microquasars, pulsars and pulsar wind nebulae, magnetars, accreting X-ray binaries, supernova remnants, and the Galactic center. These polarization measurements will help answer fundamental questions:

• What are the geometries of the flows, emission regions, and magnetic fields?• What physical processes lead to particle acceleration and X-ray emission?• What are the physical effects of gravitational, electric, and magnetic fields at

their extreme limits?

Schedule Summary1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2

20232021 20222017 2018 2019 2020

B C/D E

KDP-B SRR

F

PDR SIR LRR

Bridge

Science Operations

KDP-C CDR Launch

Funded Schedule MarginCritical Path

Mission MilestonesMission PhasesTasksSpacecraft (Ball)Payload Structure (Ball)Mirror Modules (MSFC)Detector Systems (IAPS/INFN)X-ray Calibration (MSFC)Payload I&T (Ball)Observatory I&T (Ball)Launch Operations (RTS)Launch (RTS)Commissioning/Science Ops