The Generation-X Vision Mission

The Generation-X Vision Mission The Committee on Science Opportunities Enabled by NASA's Constellation System 21 February 2008 Roger Brissenden Harvard-Smithsonian Center for Astrophysics

Outline 1. Generation-X Studies 2. Science Objectives 3. Mission Concept 4. Technical Feasibility and Challenges 5. Cost Considerations 6. Constellation System Applicability 21 Feb 08 2

1. Generation-X Studies Generation-X Vision Mission (VM) Study Gen-X mission concept proposed by Will Zhang et al in a white paper (2000) Probe X-ray emission of early universe (z=5-10) to observe the creation of the first quasars and first metals in star-burst galaxies Generation-X studied in 2004-2005 VM Study as a follow-on to Chandra, XMM-Newton, Suzaku, XEUS and Constellation-X 50-100 m 2 effective area with sub-arcsecond imaging Observe first black holes and their effect on the formation of galaxies Trace the evolution of black holes, galaxies and structure Probe matter in extreme environments Utilized NASA Design Centers to examine two concepts Multiple spacecraft with extendable optical bench Single mirror formation flying Optics are the technology driver 21 Feb 08 3

Generation-X Vision Mission Team Roger Brissenden (PI) SAO Martin Elvis Pepi Fabbiano Paul Gorenstein Paul Reid Dan Schwartz Harvey Tananbaum Rob Petre GSFC Richard Mushotzky Nick White Will Zhang Mark Bautz MIT Claude Canizares Enectali Figueroa-Feliciano David Miller Mark Schattenburg Webster Cash Colorado Martin Weisskopf MSFC Mel Ulmer Northwestern Niel Brandt PSU Robert Cameron Stanford 21 Feb 08 4 Steve Kahn Rogier Windhorst ASU and collaborators 75 People, 14 Institutions, 5 Industry Partners, 2 NASA Centers

Gen-X Astrophysics Strategic Mission Concept Study (AMCS) Proposal Gen-X proposal developed with core VM team with additional optics and industry expertise Study will build on the successful 2004-2005 VM study Revisit science case to refine mission requirements Constellation System hardware could be proposed as launch vehicle Ares V capability results in simplified and more costeffective baseline mission concept Key Study product is a detailed technology development road map 2/13/08 proposal selected! 21 Feb 08 5

Roger Brissenden (PI) SAO Martin Elvis Pepi Fabbiano Paul Gorenstein Mike Juda Paul Reid Dan Schwartz Harvey Tananbaum Simon Bandler GSFC Ann Hornschemeier Rob Petre Richard Mushotzky Will Zhang Mark Bautz MIT Claude Canizares Enectali Figueroa-Feliciano Mark Schattenburg Generation-X AMCS Team Webster Cash Colorado Martin Weisskopf MSFC 21 Feb 08 6 Steve O Dell Mel Ulmer Northwestern Niel Brandt PSU Susan Trolier-McKinstry Robert Cameron Stanford Steve Kahn Robert Rosner ANL and collaborators 67 People, 21 Institutions 5 Industry Partners 2 NASA Centers

NASA X-ray Astronomy Roadmap 2024- Chandra XMM-Newton 1999-2009+ 1999-2009+ 2017-2022+ Constellation-X 20-100 times increased sensitivity for spectroscopy First Black Holes & Galaxies Generation-X 1000 times deeper X-ray imaging 50 m 2 0.1 arc sec Astro-E2 2005-2008+ First Clusters of Galaxies 2024-0.04-0.15 m 2 1-100 arc sec 3 m 2 5-15 arc sec MAXIM 10 Million times finer MAXIM imaging Constellation-X endorsed by US National Academy of Sciences McKee-Taylor Survey as a high priority mission for this decade Black Hole Event horizon 0.1-1.0 m 2 0.1 micro arc sec 21 Feb 08 7

2. Science Objectives High-resolution X-ray Imaging Chandra s 10x increase in resolution has yielded major advances in astrophysics: Resolved 80% of 1-8 kev X-ray Background Cluster cooling gas reheated by repeated outbursts from the central Black Hole Detection of merging galaxies with central SMBH, NGC6240 Detailed studies of the distribution and dynamics of elements within supernova shocks Detailed studies of the populations in star clusters Gen-X s 10x further increase will allow study and evolution of the first stars, galaxies and black holes Gen-X complements the next generation telescopes in other bands: AMLA, JWST, SKA, TMT 21 Feb 08 8

Orion: 70 to 1400 Sources ROSAT: ~10 Chandra: ~1 21 Feb 08 9

Supernova Cassiopeia A ROSAT: ~10 Chandra: ~1 21 Feb 08 10

Generation-X Science Drivers EARLY UNIVERSE: The first black holes, stars and galaxies X-rays penetrate haze of high z IGM, and gas and dust around objects EVOLUTION: of black holes, galaxies and the elements they produce vs cosmic time X-ray observations trace baryon abundances and dark matter since much baryonic matter in form of hot gas (elliptical halos, clusters) PHYSICS: Probe the behaviour of matter in extreme environments Density, gravity, magnetic field, kinetic energy Science drivers traced to observations to mission parameters and implementation Science Drivers Key Mission Parameters Mission Implementation 21 Feb 08 11

Gen-X Key Mission Parameters Derived from Science Objectives Parameter Effective Area Angular Resolution Energy Resolution (@1 kev) Background (0.5 2.0 kev) Energy Range Field of View Time Resolution Count Rate Limit Sky Availability Calibration Baseline 50 m 2 0.1" HPD E/dE=1000 0.004 cts/ks/arcsec 2 0.1 10 kev 5 arcmin radius 50 µs 100 cts/sec/pix 90% 3% absolute 21 Feb 08 12

Detecting the First Black Holes First epoch of energy injection at z~10-20 (0.2-0.5 Gyr) - WMAP Fast burning massive stars yield SN and first black holes Must grow at Eddington limit to reach observed quasar masses Fiduicial numbers for Gen-X: Black Hole Mass 1000 solar masses Eddington Limit 6.5x10 40 erg/s Redshift 15 Flux 3x10-20 erg/cm 2 /s Effective Area 50 m 2 Angular Resolution 0.1" Count rate 5x10-6 cts/sec Exposure time 1x10 6 s (~5 counts in 1 Ms) Background rate 0.01 cts/ks/arcsec 2 Drives 50 m 2 Effective Area and 0.1" Angular Resolution 21 Feb 08 13

Merging Black Holes and AGNs Merging black holes give insight into merger tree vs. redshift X-rays can see accreting black holes even for A V =100 Gen-X: 160 ks, z=1, can detect and resolve a binary AGN 2kpc apart. Chandra image of NGC6240: two AGNs in a merger, ~1 kpc separation 0.1" resolution corresponds to physical scales of: 0.8 kpc at z=3 0.6 kpc at z=6 0.3 kpc at z=15 Hundreds of binary BH systems observable with separation of ~1 kpc Schematic Black Hole Merger Tree Drives EA=50 m 2, Ang. Res=0.1", E/ E=10 3-10 4 21 Feb 08 14

Studying Galaxy Component Evolution with z Gen-X View of the Hubble Deep Field z=1-3 galaxies show increased SFR and Lx; X-ray evolution For Hubble Deep Field, Chandra detects only 17 sources in 2 Ms Gen-X would detect most of the 3000 galaxies seen by HST ~800 galaxies at z~3 with >=400 counts in 1 Ms Spatially separate XRB from nuclear BH; spectrally separate hard XRB emission from hot gas to reveal true SFR Drives Gen-X Effective Area of 50 m 2, Angular Resolution of 0.1" and 0.1-10 KeV Energy Range 21 Feb 08 15

Gen-X View of Galaxy Evolution 200 Mpc (z=0.05) 6,000 Mpc (z=1) Simulated interacting galaxies to z=1 Gen-X sufficiently resolves the dominant X-ray binaries to allow X-ray Population Synthesis and study of galaxy evolution Study chemical evolution with SNR to 10 Mpc; high resolution spectra of Fe, Si and O drives requirement E/ E = 10 3-10 4 21 Feb 08 16

NASA Research Objectives Understand how the first stars and galaxies formed, and how they changed over time into the objects recognized in the present universe. -Physics of the Cosmos -Cosmic Origins Understand the origin and destiny of the universe, phenomena near black holes, and the nature of gravity. -Physics of the Cosmos Understand the fundamental physical processes of space plasma systems. -Physics of the Cosmos Understand how individual stars form and how those processes ultimately affect the formation of planetary systems. -Exoplanet Exploration Gen-X Key Science Objectives The First Black Holes & the First Stars The Evolution of BH & Galaxies, and heating of baryonic gas Chemical Evolution of the Universe Region near the Event Horizon of a Black Hole Relativistic Jets Stellar Magnetic Fields and Reconnection Physics Diverse Plasma Environments Embedded Star Clusters Protosta r s Gen-X Required Observations 10 6 s deep surveys to find 1000 M sol BH at z~15 emitting at L edd with flux of 3x10-20 erg cm -2 s -1 (0.1-10 kev) 10 6 s deep surveys to resolve AGN from binaries and hot gas and to measure broadband spectra in 10 41 erg s -1 galaxies at z~3. 10 4-10 5 s observations for Fe, Si and O lines from SNR to 10 Mpc, normal galaxies to 200 Mpc, clusters to their epoch of formation. Detailed, time-resolved spectra showing gravitational line distortion and rapid changes in line shape and continuum to test G.R. and measure BH mass/spin in hundreds of AGN in 10 4-10 5 s observations. Detailed images and spectra to measure knot speed and structure from imaging black hole jets. 10 5 s observation every 2 years. High-resolution X-ray spectra of stellar coronae to determine roles of magnetic field, rotation, age and mass. High-resolution X-ray spectra and plasma diagnostics for: stellar coronae, planetary magnetospheres, SNR, hot gas in galaxies and clusters of galaxies, and accretion disks in XRBs and AGN. Census of 100,000 young stars in Galactic starburst complexes (Sgr B2, NGC 3603, W49, W51, 30 Dor) Direct imaging, e.g., of the TW Hya protoplanetary disk in 10 6 s, and indirect reverberation mapping of dozens of Ophiuchus disks, using the 6.4 kev fluorescent iron line in a single 10 6 s observation. 21 Feb 08 17

3. Mission Concept Design Considerations Wolter Type I nested grazing incidence optics For 50 m 2 EA need ~10 4 m 2 of glass area Very thin mirrors ~0.1-0.2 mm to meet launch mass requirements 50 m 2 EA implies ~16 m diameter mirrors so either multiple launches and assembly, multiple satellites, or single heavy lift Mirror diameter and grazing angle of 0.5-1 deg. to meet energy range 0.1-10 kev; yields focal length of 50-150 m Energy range, FOV, time resolution, non X-ray background drive science instruments: Reflection grating spectrometer (RGS) Micro-calorimeter array (XRS) Active Pixel imager (Wide Field Imager - WFI) 21 Feb 08 18

Gen-X Telescope Parameter Comparison Generation-X Telescope Parameters Compared to Previous Missions Mission Telescope Modules Angular HPD (arcsec) Module Eff. Area (m 2 @ 1 kev) Module Mass (kg) Mirror Technology Chandra 1 0.5 0.1 1000 Zerodur Shells XMM-Newton 3 15 0.15 420 Replicated Ni Shells Astro-E2 5 90 0.04 12 Replicated Al Segments Constellation-X 4 15 (5 goal) 0.75 700 Thermally Formed or Replicated Segments Generation-X 1 0.1 50 12,300 Thin nested segments with active control 21 Feb 08 19

Baseline VM Mission Concept 6 identical telescopes 16 m 2 effective area at 1 kev 8 m diameter 50 m focal length Figure and alignments adjusted on orbit Detectors attached to deployable boom 6 separate ELV launches (e.g., Delta 4H) Telescope carried as 6 segments to fit in fairing Telescope segments deployed automatically Sun-earth L2 orbit Detectors Reflection grating spectrometer Micro-calorimeter array Active pixel imager 21 Feb 08 20

Alternate VM Concept: Single Mirror Single telescope Formation Flying 20 m diameter 125 m focal length Figure and alignments adjusted on orbit Detectors housed in separate spacecraft: formation flying 5 separate ELV launches 16 segment telescope launched as 4 sets of 4 segments each Telescope deployed autonomously Science Instrument spacecraft launched separately Sun-Earth L-2 Orbit Science Instruments Reflection grating spectrometer Micro-calorimeter array Active pixel imager 21 Feb 08 21

Gen-X Baseline AMCS Mission Ares V capability results in simplified and more costeffective baseline mission concept Single spacecraft 16 m-diameter deployable optic providing ~50 m 2 effective area Piezo-electric control of optic surface for final figure on-orbit to achieve ~0.1" angular resolution 60 m extendable optical bench between optics and science instrument package Ares V capable of delivering Gen-X directly to Sun- Earth L2 point Mirror folds and optical bench collapses for launch configuration to fit within dynamic envelope of 10 m fairing Spacecraft mass estimate of 22 Metric Ton (MT) well below Ares V 60 MT capability to L2 21 Feb 08 22

AMCS Spacecraft Configuration 21 Feb 08 23

AMCS Ares V Stowed Configuration 21 Feb 08 24

Focal Plane Layout Concept Microcalorimeter, 3 x3, ~3 M pix, position sensitive TES Grating for maximum spectral resolution at low-energy WFI, 15 x15, ~ 1G pix, 3-D integration of detector with Silicon-On-Insulator (SOI) CMOS processing for low power 21 Feb 08 25

Mission Launch Date 2025-2035 Configuration 1-tel. f=60 m Launch Ares V Orbit Sun-Earth L2 Pointing 6 arcsec Aspect 0.05 arcsec Data Rate ~50 Gbytes/day Comm. DSN: Ka, X-band Optics EA 50 m 2 @ 1 kev Angular Res. 0.1" FOV ~5 arcmin Mission Summary Science Instrument Requirements Energy Range E/ E 1000 Counting Rate Calibration 0.1-10 kev 100 /s/pixel 3% absolute Background 0.004 cts/ks/arcsec 2 Time Res. 50 µs Science Instruments XMS 3x3 arcmin of FOV 0.1 arcsec/pix E/ E~2eV @ 1 kev 21 Feb 08 26 WFI RGS Active pixel sensor Grating readout E/ E >5000 E<1 kev

4. Technical Feasibility Gen-X Technology Challenges Telescope and Optics Figure: on-orbit adjustment Modules: alignment Deployment Science Instruments XMS: array pixel count, energy resolution WFI: read noise, pixel size, dark current RGS: ruled grating Spacecraft and Mission Lift capability (single mirror) Solar collector and thermal transfer system Deployables: optical bench, sun shade VM Study found s/c at TRL 4-6 Optics are the major driver 21 Feb 08 27

Active Optics Mirror: Bimorph Piezoelectric Actuators No need for reaction structure Low power, weight Natural match to thin reflectors (0.2 mm) Mechanical actuators: hysteresis, backlash, lubricants Similar technology under development at synchrotrons Ring Focus gives separability of adjustments Consider parallel approach for ~10 6 element compute task Electrodes Mirror Piezoelectric material 21 Feb 08 28 V

Controlling Mirror Figure Axial figure error PSDs for Gen-X, Con-X and Chandra 1.10 5 1.10 6 Gen-X preadjustment 1.10 7 Radial deformation in 40 µm piezo 2 cm piezos give axial figure correction of 0.025 mm -1 Power (mm^3) 1.10 8 1.10 9 1. 10 10 Chandra Con-X 1.10 11 1.10 12 Gen-X adjusted 1.10 13 1.10 14 1.10 3 0.01 0.1 1 Frequency (cycles/mm) Gen-X Input (post-replication) PSD Gen-X Final (post adjustment) PSD Con-X Goals PSD Chandra PSD 21 Feb 08 29

Wolter I Optics Study Configuration Mission Configuration Outer Mirror Diameter (m) Inner Mirror Diameter (m) Focal Length (m) Number of Mirror Shells Field Of View (arc min) A Eff,1keV (m 2 ) 1 telescope 16 3.6 60 227 10 x 10 50 Bimorph Piezoelectric Considerations Signorato et al have used bimorph piezos in synchrotron to deform glass as long as 1 m Material: Lead Zirconate Titanate (PZT) ceramic 50 V, 10 7 ohms, 0.25 mw 5x10 6 elements = 1.25 kw or 2.5 kw including back-end electronics 21 Feb 08 30

Class/Material Mirror Materials and Fabrication Elastic Modulus, E (Gpa) Density,! (kg/m 3 ) E/! Estimated µ roughness, A rms Low = Better High = Better Low = Better Glass/Ceramic Fused Silica 73 2.20 33.2 < 5 Silicon Carbide, CVD 428 3.22 132.9 < 2 ULE 68 2.21 30.8 < 5 Zerodur 91 2.53 36.0 < 2 Borosilicate 63 2.22 28.4 < 5 Metals Aluminum 69 2.71 25.5 < 20 Beryllium 287 1.85 155.1 < 20 Silicon 131 2.33 56.2 < 5 Mirrors made to within microns of final shape Thermal forming gives near final shape Piezo-electric actuators deposited on back surface of mirror shell Reflective Au coating deposited on front surface 21 Feb 08 31

Mirror Effective Area - Baseline candidate design: 50 m 2 at 1 kev - Gold coating 21 Feb 08 32

Gen-X Encircled Energy 50% Encircled Energy in 0.1 arcsecond diameter 21 Feb 08 33

Science Instrument Technology Calorimeter: Megapixel Devices 5 x5 requires 3k x 3k elements Consider multi-level multiplexing Candidate technologies include ~10 3 SQUID serving 10 5 element arrays of 10 1 pixel position sensitive TES (cf. GSFC PoST) Active Pixel Detector: Gigapixel Devices 15 field sampled at 0.1 requires >10 8 elements Promising candidate technology: 3-D integration of detector with Silicon-On-Insulator (SOI) CMOS processing for low power Deep via interconnection in 3-D 4-side abuttable integrated active pixel imager and A to D converter (MIT/LL) Gratings: in- or off-plane reflection grating Utilize Con-X technology 21 Feb 08 34

Detector Technology SXT: Concept for position sensitive microcalorimeter pixel (Figueroa-Feliciano, 2003) WFI: 3-D interconnection architecture with low-noise CMOS (Suntharalingam et al 2005) 21 Feb 08 35

Technology Roadmap Preliminary roadmap developed to mature key technology to TRL 6 Development phased by five two-year Technology Gates (TG) Preliminary cost estimates made for AMCS for each technology development area to be focus of AMCS Study 21 Feb 08 36

Preliminary Gen-X Technology Development Roadmap System Technology Heritage Present Capability Requirement TRL TG1 TG2 TG3 TG4 TG5 Mirror Mirror Figure Mirror Modules Mirror Deployment XMM, Con-X XMM, Con-X JWST Adjust to: 10 3 Å over 1m 40Å over ~100 shells 0.1m ~200 shells aligned to ~3 aligned to 0.05 Mechanism Alignment of heritage modules to 0.05 2 3 4 5 6 2 3 4 5 6 2 3 4 5 6 XMS Multiplexing Pixel Array Suzaku, Con-X 6x6 (Suzaku) 1800 x 1800 2 3 4 5 6 Energy Resolution Suzaku, Con-X 6eV at 5.9keV (Suzaku) 2 ev@6 kev 4 5 6 Grating WFI Transmission Reflection Active Pixel Imager Einstein XMM, Chandra JWST ~5000 lp mm -1 ~10 4 lp mm -1 2-3 4-5 6 Read noise: 10e @50Hz 2e @ 1 MHz 2 3 4 5 6 Size: 2-3 4 5 6 128x128 4000x4000 Depletion pix 2 3 4 5 6 Depth: 15 m 100 m Vid. Processor: 2 3 4 5 6 36 parallel 1000 parallel 21 Feb 08 channels channels 37

5. Cost Considerations Lifecycle cost estimated for AMCS proposal Fidelity of estimate commensurate with low TRL level of key technologies Estimate involved industry and scaling of actual costs from prior missions (e.g., Chandra) where appropriate Cost estimate of ~$4B in FY08 dollars indicates a JWST or Flagship class mission 21 Feb 08 38

Candidate Lifecycle Schedule Technology development program drive by Technology Gates (TG) Gates matched to TRL maturation plan Overlaps and integrates with mission schedule to ensure system level requirements met at critical points 21 Feb 08 39

6. Constellation System Applicability Gen-X Requirement Ares V Capability Mass to Sun-Earth L2 (metric tons) >22.3 59.4 Shroud Inner Diameter (m) >8.2 8.77 Shroud Height (m) >16.9 17.2 Availability Date 2025+ ~2020 Applicability 21 Feb 08 40

Ares V Stowed Optics Configuration Concept 21 Feb 08 41

Ares V Stowed and Deployed Optics Concept 21 Feb 08 42

Conclusions Gen-X key science goals: observe the first black holes, stars and galaxies, and trace their evolution Large area: 50 m 2, high resolution: 0.1" requires innovative active approach to mirror figure control Study baseline: 16 m-diameter deployable optic 50 m 2 effective area 60 m focal length SI s on extendable boom Ares V Launch to L2 Technology development plan next step with optics the driver: AMCS selected Ares V enables Gen-X: streamlined and cost effective mission design and launch 21 Feb 08 43