Autonomous Large Distributed CubeSat Space Telescope (ALDCST) ASTE 527: Space Exploration Architectures Concepts Synthesis Studio Midterm Presentation October 16, 2012 Professor: Madhu Thangavelu Concept Presentation: Jesus Isarraras

BACKGROUND / HISTORY NASA – Hubble Space Telescope; ~570km LEO orbit; 2.4m mirror aperture – James Webb Space Telescope scheduled for launch in 2018; 1.5M km (Earth-Sun Lagrangian L2) orbit; 6.5m mirror aperture – Studying next generation UVOIR space observatory through the Advanced Technology Large-Aperture Space Telescope (ATLAST) California Polytechnic State University & Stanford – Developed CubeSat Standard Cal Tech & University of Surrey – Autonomous Assembly of a Reconfigurable Space Telescope (AAReST) Technology Development – Surrey Training Research and Nanosatellite Demonstrator (STRaND) payload development for AAReST Naval Post Graduate School – Pseudospectral Estimation for optimal controls problems 2

RATIONALE Develop key technologies and architectures for large space apertures to improve the capability of future imaging and sensing using CubeSat innovations 3

ATLAST-8m ATLAST-9.2m ATLAST-16m TIMELINE OF TECHONOLOGIES FOR ADVANCED TELESCOPES ’s 1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q STRaND-1 S-Android Logo STRaND-2 S-Android Logo ARReST JWTS Direct Tech Insert Payload contains Google Nexus Smartphone; Nexus will fully control nanosat Kinect Tech for 3D modeling spacial awareness Kinect

ASSUMPTIONS / GROUNDRULES Time frame: 10 years Successful STRaND – 1 mission in 2012 Successful STRaND – 2 mission in 2014 Successful ARReST mission in 2015 Successful JWTS launch and mission in 2018 Adaptive Optics Gap size between sub-mirrors is < 0.01D; aberration is minimized 5

CONCEPT - PROPOSAL Provide an alternative architecture for large primary mirror (D>20m) for space telescopes – Alternative for next generation UVOIR telescopes (e.g ATLAST) – CubeSat cluster with segmented mirrors – Autonomous formation and control Potential Benefits – Potential lower cost and mass – Mirror segment replacement – Removes human activity for fielding – Faster production/manufacturing 6

CONCEPT - LOCATION Direct extrasolar planetary observations become possible with large (D>20m) apertures – Earth-Sun Lagrangian point L2 – Opportunity to study early universe phenomena, monitor extremely faint and distant galaxies, dark matter and dark energy 7

CHALLENGES Deployable mirror segment alignment Achieving high surface accuracy of a large segmented mirror (optical figuring) Surface and structure control stabilization Vibration isolation and potential jitter control Control of adaptable/flexible mirrors  Wavefront sensing and correction (sensors)  Thermal management/distortion mitigation  Power management of segmented architecture 8

COMPLEX SUBSYSTEMS Architecture - Structure Launcher to hold multiple layers Layers deployed in sequence Each layer contains 6 segments Each segment contains N mirrors N Nth Layer 1 1 st Inner Layer (center) 2 2nd Inner Layer Launcher 9

COMPLEX SUBSYSTEMS Architecture - Structure Nth CubeSat Layer of Mirror Top view of Nth Layer Expands to create Hexagon Shape Hex-Frame: provides stability and links Pod’s together Flexible joints connecting sat’s Top view of Nth Layer 10

COMPLEX SUBSYSTEMS Architecture - Structure Autonomous formation Control −ADC −Advanced algorithms (e.g PS) Sensing −Lasers, optical, IR Actuation −Cold Gas, PPT, Hall Comm −Short range wireless −LOS Wireless −Laser 11

COMPLEX SUBSYSTEMS Architecture – Structure Layers 100 mirrors 99 mirrors 100 mirrors 99 mirrors Total Mirrors: 30,300 Total CubeSats:30,300 Total Layers: 5,050 Total Segments:

CONCEPT - COMPLEX SUBSYSTEMS Architecture – Deformable Mirror Thin deformable mirrors with integrated actuators – >200 independent actuators – Wavefront correction for each mirror (algorithms) – Improved light gathering power – Improved resolution – Thermal management through shape/curvature correction 370μm 13 Primary material: Polyvinylidene flouride (PVDF)

CONCEPT - COMPLEX SUBSYSTEMS Architecture – Advanced GN&C Pseudo-spectral estimation – GN&C stability of complete cluster structure – Optimal motion planning for autonomous vehicles in obstacle rich environments – Constraint Non-Linear Problems The Zero Propellant Maneuver demonstrated on the ISS. November 5, 2006 rotated 90 deg and March 3, 2007 rotated 180 degrees Autonomous Reentry and Decent of Reusable Launch Vehicles 14

CONCEPT - EVOLUTION Mirror packaging Mirror wavefront sensors Flight formation sensors Adaptive optics systems Mirror actuators CubeSat P-POD and dimension growth Instrumentation (cameras, sensors, etc) 15

CONCLUSIONS Large apertures can be created through CubeSat Cluster design Segmented and adaptable mirrors future of telescope design Complex CubeSat architectures affordable options of the future 16

FUTURE QUANTITATIVE STUDY Secondary Mirror Deployment Aberration and Mirror stabilization Orbit definition Thermal management of cubesat’s and system architecture (e.g Passive – radiate heat to space vs active – refrigerator system) Sun shield technology Radiation hardening requirements Power Management Communication architecture 17

REFERENCES 1.Patterson, K., Yamamoto, N., Pellegrino, S. (2012). Thin deformable mirrors for a reconfigurable space telescope. Retrieved from 2.Postman, M. (2009). Advanced Technology Large Aperture Space Telescope Study NASA. Retrieved from Keck Institute for Space Studies. (2012) 4.Steeves, J., Patterson, K., Yamamoto, N., Kobilarov, M., Johnson, G., Pellegrino, S. (2012). AAReST Technology Development. Retrieved from 5.Patterson, K., Pellegrino, S., Breckinridge, J. (TBD) Shape correction of thin mirrors in a reconfigurable modular space telescope. Retrieved from: breckinridge.pdfhttp:// breckinridge.pdf 6.McClellan, J. (TBD). Aurora Flight Sciences CubeSat Cluster. Retrieved from: _presentation_mccellan_ pdf _presentation_mccellan_ pdf 7.Padin, S. (2003). Design Considerations for a Highly Segmented Mirror. Retrieved from: Postman, M. (2007). Advanced Technology Large-Aperture Space (ATLAS) Telescope: A Technology Roadmap for the Next Decade. Retrieved from: Fundamental Optics. Retrieved from: Naval Post Graduate School. (2012). Conference Papers. Retrieved from:

Thank you for your time! Jesus Isarraras 19

BACKUP CHARTS 20

CONCEPT - COMPLEX SUBSYSTEMS Large Space Aperture Architecture Comparison ALDCSTHSTJWST Herschel Space Observatory Type of MirrorSegmentedMonolithicSegmentedMonolithic Primary Aperture (m) / Mirror Mass (kg) 635 (mirrors, actuators) (full telescope) Wavelength ( μm) (UV,IR) 0.8 – 2.5 (IR) 0.1 – 0.8 (UV, visible) 0.6 to 28 (IR)60 to 500 (IR) Orbit Earth-Sun L2 Lagrange point; 1.5 million km LEO; 570km Earth-Sun L2 Lagrange point; 1.5 million km Resolution10 μm in IR 0.1 arcsec in red light; Main camera; 16M pixels 2 μm in IR Main camera: 32M pixels 5 – 50 arcsec Size (L x W) (m) TBD13.2 x x 129 x 4.5 Mission Length 10 yr? yr>3 Total Dev Cost ($M) <$1B$1.5B$1B €1.1 21

Preliminary Mass Calculations From Patterson, K., Pellegrino, S., Breckinridge, J. Shape correction of thin mirrors in a reconfigurable modular space telescope Complete mirror structure w/ areal density ~2kg/m^2:

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COMPLEX SUBSYSTEMS Architecture - Structure Hex-Frame Contains ADC Comm Link Enhancement Layer Stabilization Network Communication 24

CONCEPT - COMPLEX SUBSYSTEMS Architecture – Secondary Mirror & Instruments 6U CubeSat 10cm Secondary Mirror Deployer Instruments (Camera, Optical/IR Sensors, etc) Focal Plane Detector 25

Formation Flying Control Challenges Complexity – Systems of systems (interconnection/coupling) Communication and Sensing – Limited bandwidth, connectivity, and range – What? When? To whom? – Data Dropouts, Robust degradation Arbitration – Team vs. Individual goals Resources – Always limited, especially on a CubeSat 26

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Hubble Space Telescope Payload: Optics: The telescope is an f/24 Ritchey-Chretien Cassegrainian system with a 2.4 m diameter primary mirror and a 0.3 m Zerodur secondary. The effective focal length is 57.6m. The Corrective Optics Space Telescope Axial Replacement (COSTAR) package is a corrective optics package designed to optically correct the effects of the primary mirror's aberration on the Faint Object Camera (FOC), Faint Object Spectrograph (FOS), and the Goddard High Resolution Spectrograph (GHRS). COSTAR displaced the High Speed Photometer during the first servicing mission to HST.

Hubble Space Telescope Instruments: The Wide Field Planetary Camera (JPL) consists of four cameras that are used for general astronomical observations from far-UV to near-IR. The Faint Object Camera (ESA) uses cumulative exposures to study faint objects. The Faint Object Spectrograph (FOS) is used to analyze the properties of celestial objects such as chemical composition and abundances, temperature, radial velocity, rotational velocity, and magnetic fields. The FOS is sensitive from 1150 Angstroms (UV) through 8000 Angstroms (near-IR). The Goddard High Resolution Spectrometer (GHRS) separates incoming light into its spectral components so that the composition, temperature, motion, and other chemical and physical properties of objects can be analyzed. The HRS is sensitive between 1050 and 3200 Angstroms.