1. Space Engineering 2 © Dr. X Wu, 2008 1 Space Engineering 2 Lecture 1

2. Space Engineering 2 © Dr. X Wu, 2008 2 Literature  James R. Wertz and Wiley J. Larson, Space Mission Analysis and Design (SMAD), 3 rd Edition, EI Segundo, CA, Microcosm Press, 1999.  Peter Fortescue, Spacecraft Systems Engineering, 3 rd Edition, Wiley, 2003.

3. Space Engineering 2 © Dr. X Wu, 2008 3 Objectives  Knowledge of systems engineering aspects of designing spacecraft.  Knowledge of the Space Environment & its Effects.  Knowledge of Spacecraft Bus Subsystems & Design;  Ability to perform Space Mission Analysis & Design;  Document the design process in sufficient detail that another engineer can continue on with the work just by going through the log book.

4. Last Year’s CubeSat Designs Space Engineering 2 © Dr. X Wu, 2008 4

5. Presentations & Labs  Presentations  Preliminary Design Review (5%)  Critical Design Review and Test (5%)  Labs  ADCS on Airbearing table (10%)

6. Nanosatellite Fundamentals ”The Design Space” Dr. Xiaofeng Wu

7. MinisatelliteMicrosatelliteNanosatellitePicosatelliteFemtosatellite £10-50M£1-10M£1-2M£10-100K£100-1000 100-500kg10-100kg1-10kg0.1–1kg1-100g CubeSatPCBSat ChipSatPalmSatSnap-1 PICOSat UK-DMC Future Space Engineering  Trends in Future Spacecraft  Miniaturized  Autonomous and intelligent  Distributed   Application Domain  Remote monitoring, diagnostics and self-repair  Co-orbiting assistants/inspectors of larger spacecraft  Virtual satellite missions  Interplanetary applications

8. Selected Nanosatellite Topics  Introduction  What is a Picosatellite  History of Missions  Proposed Missions  Basic Design Space  More?  Supporting Technology  Constellation design  Intersatellite Links  Reconfigurable computing  Distributed processing  More?

9. What is a Picosatellite  Mass less than 1 kg, larger than 100g  Typically on the order of 10 cm 3 volume  At the edge of technology for  Meaningful downlink  Single-sat constellation  Well suited for  “Distributed Satellite Missions”

10. History of Missions  Not to be confused with ill- named USAF mission “PICOSat” (SSTL  sat)PICOSat  OPAL 2000 OPAL 2000  2 of 6 successful  Each custom designed  Eurockot Launch 2003 Eurockot Launch 2003  3 of 5 successful  All “CubeSat” bus types (Stanford/Cal Poly standard)CubeSat  SSETI Express 2005 SSETI Express 2005  2 of 3 successful  Again, all “CubeSats”

11. Proposed missions  Several Nanosats in the works, watch for:  Micro-Link 1, Ångström Aerospace, Swedish & Canadian joint-effort targeting mass-production  Recent Picosat concepts proposed  PalmSat (SSC)  More CubeSats  Japan, others  Website advertises 40+ current universities  Others?

12. Picosat Design Space - Problem Areas -  Single-sat missions virtually useless, except for education  Low power budget  Low data rate downlink  No room for conventional propulsion

13. PC-104 COTS Picosatellite Concept  PC104 COTS standard  150+ vendors  Many types available  Focused on rugged Military/Embedded apps  5-module stack  For rapid prototyping  10 cm 3 volume, ~1 Kg  Start with 3 COTS modules:  FPGA, Wireless, GPS  Add custom Payload, EPS, AOCS, TCS

14. COTS pico-satellite design Shown: Qualified OBC (MSP430) / FPGA (Xilinx Virtex4) / Communications (Elcard 802.11 Wireless Board) / Qualified EPS (Clyde Space) / Structure by CubeSat Kit

15. CubeSat Components  Structure  Command & Data Handling with high- frequency transceiver and antennas  Communications (COM)  Electrical Power System (EPS)  Solar Cells  Attitude Determination & Control System (ADCS)  Payload

16. CubeSat Developed at SSC

17. PhoneSat

18. Phone (Nexus One) Core UHF Radio 440 MHz Likely Core Extra Battery Bank (12 x 18650 3.7V cells, 2800 mAh) Legend Monopole Antenna Custom PCB Spacecraft 1.0 Concept A With UHF radio & Hardware battery override & Watchdog/Lazerus Watchdog/ Lazerus (Arduino) Power Data PhoneSat 1: System Architecture

19. Why use a phone?  Increase on-orbit processor capability by a factor of 10-100  Decrease cost by a factor of 10-1000  Free up cubesat volume for additional payload through avionics miniaturization  Demonstrate COTS approaches to all subsystems (ie, power, RCS, comms)  Produce high-capability spacecraft for $1- 10k (exc. LV)

20. Nexus One Android OS 1 GHz Processor 500 MB RAM 16GB Data Storage 3-axis accelerometer, 3-axis magnetometer 5MP Camera/VGA Video Camera GSM, WiFi, Bluetooth, FM radio GPS (restricted)

22. PalmSat

23. Satellite-on-a-PCB (PCBSat)  Dimension: 9x9.5cm, compatible with PC104 form factor  Mass: ~200g  Power: 650mW peak

24. Satellite-on-a-Chip (ChipSat) CMOS imager (lens) Solar self- powered (<1% eff.) Data Handling (radiation) RF Comm on a chip (<1 km range) Attitude/ Orbit Control (2-sided) (no propulsion) Thermal Control (heat sink) Configuration: CMOS, <10g, 20x20x3 mm (largest die possible) It’s possible, but: Mission utility is main issue—too small

25. Possible Missions for CubeSat  Distributed computing  Pico-satellite constellation  Formation flying  On-board signal processing  Optical signal  Radar signal  Electromagnetic signal  Thermal signal

26.  Possible Missions  Communication  Global communication for handheld terminals. –Little LEO systems: ORBCOMM constellation  Semantic web service –The Web, once solely a repository for text and images, is evolving into a provider of services— information-providing services, such as flight information providers, temperature sensors, and cameras, and world-altering services, such as flight-booking programs, sensor controllers, and a variety of e-commerce and business-to-business applications –Grid computing on satellite constellation using the on-board computers to provide prompt web services

27.  Space Weather Monitoring  Adverse conditions on the Sun in the Solar Wind and in the Earth’s magnetosphere, ionosphere and thermosphere  Influence the performance and reliability of space- borne and ground-based systems and endanger human life or health.  Space weather sensors –Telescope: improve the observation capabilities. –Special Sensor Ultraviolet Limb Imager (SSULI): measure the natural airglow radiation from atoms, molecules and ions in the upper atmosphere. –Special Sensor Ultraviolet Spectrographic Imager (SSUSI): measure ultraviolet emissions in five different wavelength bands from the upper atmosphere. –Solar X-Ray Imager (SXI): provide x-ray imagery of the disk and corona of the sun.

28.  Earth observing  Disaster monitoring –DMC constellation: 5 micro-satellites in LEO, optical imaging payload –Optical sensing: fire, flood –Electromagnetic sensing: earthquake (QuakeSat) –Radar imaging –On-board signal processing »Encryption »Data compression »Intelligent on-board signal analysis and decision making

29. TS3: links separate telescopes together to produce one large image. NASA Terrestrial Planet Finder (TPF): Planet search and imaging Formation Flying Concept TechSat-21: Autonomous Agent Experiment (Project cancelled due to complexity of problem and budget overruns) NASA Ants Framework: Reconfigurable Computing, Autonomy, MEMs instruments for Distributed Space Missions

30. Space Engineering 2 © Dr. X Wu, 2014 30 What is a Space System  Ground  Spaceflight Operations  Payload Operations  Payload Data Processing  Space  Orbits  Spacecraft  Launch  Launch Vehicle Integration  Launch Operations

31. Space Engineering 2 © Dr. X Wu, 2014 31 Ground  Ground Activities:  Spacecraft Flight Operations  Payload Operations  Payload Data Processing  Payload Data Dissemination  Facilitated By:  Real-Time Processing  Payload Dissemination Infrastructure  Powerful Payload Processing Facilities  Mission Simulations Can Be Merged

32. Space Engineering 2 © Dr. X Wu, 2014 32 Launch  Selection:  Enough “throw weight”  Enough “cube” (volume)  Acceptable ride  Good record…  Integration:  Launch loads imparted to spacecraft  Mechanical/Electrical Integration

33. Space Engineering 2 © Dr. X Wu, 2014 33 Space Mission Architecture

34. Space Engineering 2 © Dr. X Wu, 2013 34 Payloads and Missions MissionTrajectory type CommunicationsGeostationary for low latitudes, Molniya and Tundra for high latitudes (mainly Russian), Constellation of polar LEON satellites for global coverage Earth ResourcesPolar LEO for global coverage WeatherPolar LEO, or geostationary NavigationInclined MEO for global coverage AstronomyLEO, HEO, GEO and ‘orbits’ around Lagrange points Space EnvironmentVarious MilitaryVarious, but mainly Polar LEO for global coverage Space StationsLEO Technology DemonstrationVarious Note: GEO – Geostationary Earth Orbit; HEO – Highly Elliptical Orbit; LEO – Low Earth Orbit; MEO – Medium height Earth Orbit

35. Space Engineering 2 © Dr. X Wu, 2013 35 Objectives and Requirements of a Space Mission

36. Space Engineering 2 © Dr. X Wu, 2013 36 Space System Development  All systems development start with a “mission need” (the Why)  Then mission requirements are developed to meet this need (the What) often along with a concept of operations  Note: Often we make the mistake of putting “the How” in the Mission Requirement  From 1 and 2 above develop derived requirements for (the How):  Space  Mission orbit  Payload Types (Communications, remote sensing, data relay)  Spacecraft Design  Ground  Facilities and locations  Computers/Software  Personnel/Training  Launch segments  Note: The requirements generation process is often iterative and involves compromises

37. Space Engineering 2 © Dr. X Wu, 2013 37 Requirements of a Spacecraft 1.The payload must be pointed in the correct direction 2.The payload must be operable 3.The data from the payload must be communicated to the ground 4.The desired orbit for the mission must be maintained 5.The payload must be held together, and on to the platform on which it is mounted 6.The payload must operate and be reliable over some specified period 7.All energy resource must be provided to enable the above functions to be performed

38. Space Engineering 2 © Dr. X Wu, 2013 38 Spacecraft Subsystems Space Segment PayloadBus Structure Mechanisms Attitude and orbit control ThermalPropulsion PowerTelemetry and command Data handling

39. Space Engineering 2 © Dr. X Wu, 2013 39 Spacecraft Description  Spacecraft have two main parts:  Mission Payload  Spacecraft Bus  Mission Payload  A subsystem of the spacecraft that performs the actual mission (communications, remote sensing etc.)  All hardware, software, tele- communications of payload data and/or telemetry and command  There can be secondary payloads  Spacecraft Bus Hardware & software designed to support the Mission Payload  Provides  Power  Temperature control  Structural support  Guidance, Navigation & Control  May provide for telemetry and command control for the payload as well as the vehicle bus

40. Space Engineering 2 © Dr. X Wu, 2013 40 Spacecraft Development Process  Some types:  Waterfall (sequential)  Spiral (iterative)  Basic Sequence: 1.Conceptual design 2.Detailed design 3.Develop detailed engineering models 4.Start production 5.Field system 6.Maintain until decommissioned  DoD mandates integrated, iterative product development process Requirements Development Detailed Design Engineering Development & Production Field (IOC)

41. Space Engineering 2 © Dr. X Wu, 2013 41 Serial (waterfall) Development 1.Traditional “waterfall” development process follows logical sequence from requirements analysis to operations. 2.Is generally the only way to develop very large scale systems like weapons, aircraft and spacecraft. 3.Allows full application of systems engineering from component levels through system levels. 4.Suffers from several disadvantages: Obsolescence of technology (and sometimes need!) Lack of customer involvement/feedback Difficult to adjust design as program proceeds http://www.csse.monash.edu.au/~jonmc/CSE2305/Topics/07.13.SWEng1/html/text.html

42. Space Engineering 2 © Dr. X Wu, 2013 42 Spiral Development From: http://www.maxwideman.com/papers/linearity/spiral.htmhttp://www.maxwideman.com/papers/linearity/spiral.htm And Barry Boehm, A Spiral Model of Software Development and Enhancement, IEEE Computer, 1988 Software Development Centric Example Good features 1.In this approach, the entire application is built working with the user. 2.Any gaps in requirements are identified as work progresses into more detail. 3.The process is continued until the code is finally accepted. 4.The spiral does convey very clearly the cyclic nature of the process and the project life span. Not so good features 1.This approach requires serious discipline on the part of the users. The user must provide meaningful realistic feedback. 2.The users are often not responsible for the schedule and budget so control can be difficult. 3.The model depicts four cycles. How many is enough to get the product right? 4.It may be cost prohibitive to “tweak” the product forever. Simply put: Build a little – Test a little! Can this work for every type of project?

43. System Development Process  ‘Breadboard’ system  Concept development and proof of concept  Prototype  First draft of complete system  Implements all requirements  Engineering model  Complete system without final flight configuration  Plug and play with flight model  Flight model  The final product  Space-ready product, implements all requirements

44. Design Review  Preliminary Design Review (PDR)  Architecture and interface specifications  Software design  Development, integration, verification test plans  Breadboard  Critical Design Review (CDR)  System Architecture  Mechanical Design Elements  Electrical Design Elements  Software Design Elements  Integration Plan  Verification and Test Plan  Project Management Plan

45. Spacecraft Integration and Test  Methodical process for test of spacecraft to validate requirements at all levels  Sequence: 1. Perform component or unit level tests 2. Integrate components/units into subsystems 3. Perform subsystem tests 4. Integrate subsystems into spacecraft 5. Perform spacecraft level test 6. Integrate spacecraft into system 7. Perform system test when practical