PayloadsCharacteristics of Space Used By Various MissionsPayload Categories and Typical ApplicationsRoadmap to Payload Design and SizingPayload Selection and Design ProcessKey Issues in Payload Design ProcessPayload Performance SizingSubject TradesFIRESAT Subject TradePayload DesignPayload Design SummaryPayloadsAERSP 401ACharacteristics of Space Used By Various MissionsCharacteristic Relevant Missions Degree of Utilization Sample MissionsGlobal perspective CommunicationsNavigationWeather SurveillanceSome are mature industries; major new advances will come with increased on-board processingIntelSatNAVSTAR/GPSNOAA satellitesDSPIkonosAbove the atmosphereScientific observations at all wavelengthsWell developed; space observatories will continue to dramatically change our view of the universe•NASA’s Great Observatories• Hubble•Compton GRT (deorbited)•Chandra•SIRTFGravity-free environmentMaterials processing in spaceNow in infancy; may be large future applicationsIndustrial Space FacilityInternational Space StateSpace ShuttleAbundant resourcesSpace industrializationAsteroid explorationSolar power satellitesEssentially none Space coloniesSolar power satellitesExploration of space itselfExploration of Moon and planets, scientific probes, asteroid an comet missionsInitial flybys and orbiting has been done; Some landings done or planned; limited manned explorationManned lunar or Martian basesApolloVoyagerGalileoCassiniPayload Categories and Typical ApplicationsCOMMUNICATION SPECIALSCIENTIFIC(including Manned)APPLICATIONSComm. LinksCivil comm.Military strategicMilitary tacticalRelayINTELSATDSCSIrridiumEarth lookingRemote sensingEarth resourcesWeatherReconnaissanceEarly warningNuclear burstBoost phase trackingFire detectionOceanographyLandsatSPOTDMSPGOESDSPOtherNavigationMfg. In spaceSolar power relaySearch and rescueSpace Station S/C repairGPSSpacelabEarth orbitingPlanetaryTelescopesSpace platformsSpace stationShuttlesBiologicalSolarStellarSTS/ISSSpace TelescopesPioneerVoyagerGalileoDefensiveOffensiveSpace-Based LaserParticle beamsSDIOASATSMinesOtherIntelligenceELINTSIGINTJammingTethersBurial-in-SpaceTugsRoadmap to Payload Design and Sizing•Enormously wide range of space payloads•Payload design varies dramatically from mission to mission and is critical to mission success–Must have assistance of a payload designer who is expert in the specific payload field from the early stages of the programWhen done right, payload design is a cooperative venture When done right, payload design is a cooperative venture between the space mission engineer and the payload designerbetween the space mission engineer and the payload designerPayload Selection and Design ProcessStep Where Discussed1. Establish Top-Level Objectives 1.32. Do Subject Trades 3.13. Select number and type of instruments and broad spectral, energy, or size regime9.3.2 (Observation), 13.1 (Communication)4. Define mission operations approach 9.3.2 (Observation), 13.1 (Communication)5. Size the principal instrument(s) 9.4.3-5 (Observation), 13.3-4 (Communication)6. Iterate on steps 2-57. Select design features 9.4.6 (Observation), 13.3 (Communication)8. Define support (bus) requirements 9.4.7 (Observation), 13.4 (Communication)9. Ask: Does the system meet mission objectives at the lowest weight, cost, and complexity?Chapter 39.2 (Observation), 13.1 (Communication)10. Iterate on steps 2-811. DocumentKey Issues in Payload Design Process1. Objectives•What are the mission objectives?•What characteristics of space are we exploring2. Subject Trades•What is the subject?•What different ways are available to observe or interact with?3. Instrument Number and Type•Are multiple instruments appropriate?•Will they work well together?4. Concept of Operations (CONOPS)•Coverage mechanism?•Tasking and scheduling?•Data or material collected?•How sent to users?•Mission timelines?5. Instrument Sizing Trade Altitude Aperture Resolution Sensitivity Dwell Swath width Duty cycle FOV size Pointing Coverage6. Design Features•Frequency bands•Polarity•Optical or antenna design•Mechanical configuration•Details of subject interaction•Details of operations7. Support Requirements•Payload size, weight, and power•FOV requirements•Pointing, stability, and slewing•Duty cycle, data rates•Environmental constraints (thermal, sun angle)Payload Performance Sizing•High Performance Option–Obtain best available performance–Used in some science and military missions–Examples: HST, Compton, Chandra, Classified•Low-Cost Option–Obtain modest performance at low cost–Used for many small satellites and some experiments–Examples: GAS, Piggybacks, Micro/Nanosats•Optimized Performance vs. Cost–Obtain highest available performance per dollar–Used in commercial programs, especially communications–Examples: IntelSat, Iridium, TeledesicSubject Trades•The subject is what the payload interacts with or looks at.•Passive (Uncontrollable) Subjects–Characteristics may be known, but cannot be altered–Includes such things as weather and space environment–Options may exist, even though subject cannot be controlled•Controllable Subjects–Characteristics are known and may be altered–Include ground stations, antennas, and receiversThe subject is part of the the system trade.The subject is part of the the system trade.FIRESAT Subject Trade•What is the subject?–Heat–Fire–Smoke–Atmospheric composition•How do we observe it?–IR (heat)–Visible (fire, smoke)–Lidar (atmospheric composition)Selection of the subject and how to observe it are fundamental Selection of the subject and how to observe it are fundamental trades that should be revisited as the design evolvestrades that should be revisited as the design evolvesPayload Design•Need to be able to:–Make broad first guesses at some of the major parameters–Evaluate instrument types–Develop list of key questions for discussion with payload expert(s)–Estimate critical payload parameters based on assumed parameters–Determine and do system level trades based on key parameters and input from payload expert–Estimate payload size, weight, and powerPayload Design Summary•Can develop very preliminary estimates of payload parameters•Need inputs from individuals knowledgeable in specialized payload design from the time of mission conception–These issues are critical to mission success and there is a real