PowerPoint Presentation

Near Earth Asteroid Detection SystemTechnology Validation Mission Design Review

Project ManagerJesus OrozcoAssistant Project ManagerJeff CampbellAdvisorDr. HylandAERO 426 Space Systems Design

112Table of ContentsOverview..3Background Information....4Mission Statement..8Requirements..9Design Results11Mission Overview14Observation Candidates....15Light Gathering Optics...22Formation.....30GNC & Communication.....39Propulsion48Power & Thermal52Structures....60Mass Estimate....69Budget & Schedule.70Conclusions.....73Appendix I: References.....75Appendix II: Asteroid Occultations...78OverviewBackground InformationMission StatementIntroductionRequirementsMission OverviewObservation Candidates & Performance Evaluation GroupLight Gathering Optics Design GroupFormation Design GroupGNC & Communications GroupPropulsion GroupPower & Thermal GroupStructures GroupBudget & ScheduleConclusions3Background InformationMany objects hit Earth all the timeSometimes these objects are large enough we can notice them and they can cause damagesChelyanbinsk February 15, 2013

4Conventional Method of Observing5

Basic technique: A set of observers note the time and duration that a star disappears from sight. Then plot the ground track of the asteroid during the occultations and get the asteroid shape (silhouette)This seems very straightforward, so whats left to learn?Answer: The simple technique assumes the asteroid is big enough (10s to 100s of km) to cast a sharp shadow. Small asteroids (like Apophis) may create interference patterns, not well defined shadows!

5NEA Detection SummaryDiameter(m)>10001000-140140-4040-1Distance (km) for which F>100(=0.5 m)>20 million< 20 million,> 400,00032,000(GEO orbit)20H (mag)17.7517.75-22.022.0-24.75>24.75N estimated966`14,000~285,000??N observed8994,5572,2591,685O/E93%~33%~1%??Only 1% detected, and if you wait for sharp shadows, its probably too late6Stellar Occultation SystemArray of light collecting apertures, each equipped with a photo detectorDistant star

PhaseRetrievalalgorithm

HuygensFresnelInversionResolved silhouetteShadow pattern7Mission StatementThe mission objective is to validate advanced stellar occultation technology capable of detecting small, potentially hazardous Near Earth Asteroids.

8Top-Level RequirementsAddress the complete system, including the CubeSats, their formation, data links, ground system, etc.Each CubeSat must host a 10cm diameter telescope and light intensity detector.Assume visible light with wavelength centered at 0.5 mPlan for a minimum of 12 and a maximum of 96 CubeSats.Ground station in CS9Deploy the CubeSats in LEO with orbit lifetime no greater than 18 monthsCubeSat array must be capable of recording the shadow pattern of a 40m asteroid at 1 AU distanceIntensity detectors should be capable of recording light from a 12th magnitude star with Signal-to-Noise Ratio (SNR) of at least 10. (~80 observations possible).Obtain silhouette of asteroids in the 40 to 140m range with at least 10 pixels across.Cost < $15MTop-Level Requirements10Design ResultsTwo satellite designs: Optic and Master15 Optic Satellites, 1 MasterY-formation in Low Earth Orbit at 450kmIndependent Pegasus LaunchDeployable Cassegrain Optic with photodiode

11Optic Satellite

Master Satellite12

13Mission OverviewPlanning & DevelopmentProductionInitial LaunchNormal Mission OperationsEnd-of-life Disposal14Observation CandidatesTechnical Group LeadJohn Maksimik

Team MembersRamon CalzadaKimberly EllsworthJordan HeardKristin NicholsJesus Orozco15Technology: occultation of asteroid within 40 -140 m diameterTechnology Validation: Most known occultations involve large asteroidsAlthough the technology will be validated on larger asteroids, the array is sized for 40 140 mInstead of occulting a large asteroid, we will occult the first ripple coming off of the shadow of the asteroidUse the shadow data to determine the distance to the asteroid and the diameter of the asteroidAdequate SNR is necessary to observe the shadow ripplesObservation Candidates16Shadow Ripple

LengthIntensity17Signal to Noise Ratio

Constant array width of 3.75kmDark count of 365kHz total18*Diameter- circular distance around arrayList of AsteroidsAsteroid DateDiameterRipple LengthStar Magnitude241 Germania22 Jan 2014184 km427 m9.47 Iris27 Jan 2014253 km432 m8.7194 Prokne4 Feb 2014167 km434 m9.251 Nemausa23 Mar 2014166 km397 m9.7172 Baucis24 Mar 201467 km435 m6.751 Nemausa28 Mar 2014166 km404 m7.7776 Berbericia21 Apr 2014150 km504 m10.1105 Artemis3 May 2014 116 km410 m7.734 Circe4 May 2014117 km383 m7.4206 Hersilia7 May 201494 km409 m7.519Asteroid DateDiameterRipple LengthStar Magnitude451 Patientia12 May 2014235 km445 m8.513 Egeria1 Jun 2014215 km374 m9.6103 Hera30 Jun 201483 km358 m6.1386 Siegena2 Aug 2014208 km409 m9.8409 Aspasia21 Aug 2014183 km365 m10.481 Terpsichore4 Oct 2014134 km389 m11.0270 Anahita7 Oct 201447 km279 m9.9238 Hypatia24 Nov 2014169 km401 m11.07 Iris28 Nov 2014253 km431 m10.13 Juno28 Nov 2014290 km346 m9.0702 Alauda18 Dec 2014219 km425 m6.2List of Asteroids20

241 GermaniaRipple length: 427 mDate: 22 Jan 2014Caribbean, MexicoStar: TYC 1354-00434-1 mag 9.4Diameter: 184 km21Light Gathering OpticsTechnical Group LeadChris McCrory

Team MembersEmily BosterJeffrey CampbellDaniel CharlesJoseph DugganVianni Ricano22Solid works model

23Boom Length

Primary Mirror Diameter

Focal Length

Distance between primary and focal plane

Secondary diameter

Radii of curvature of primary and secondary mirrors

Spot Diagram

Zemacs Optical Design2411/26/2013Mirror TypeDiameterRadius of CurvaturePrimary Mirror7.0 cm-64.7421 cmSecondary Mirror.52 cm-5.0125 cmCassegrain Telescope

Distance Between Mirrors: 30.0 cm

Distance Between Primary and Photodiode: 3.0 cm

Focal Length: 6.0 m25Spot Diagrams

Radius235.7 m

26Spectral Range400-1000 nmPeak Wavelength500 nmBandwidth20 MHzDark Count Rate365 kHzDark Current100 nAActive Area3X3 mm2Operating Temperature Range0 C - +30 CPower Requirements+5VPrice per Unit$ 700 Total Price (15 optic sats)$ 10,500

SensL MiniSM Silicon Photomultiplier 30035 seriesAvalanche Photodiode set in Geiger mode

27

Weight70 gDimensions (H X W X L)45 X 35 X40 mm3Built in Peltier thermoelectric cooling system

Coaxial CablePhotomultiplier28Formation Design GroupTechnical Group LeadJoshua Kinsey

Team MembersHope RussellCandace HernandezJose LongBrian MusslewhiteBrigid Flood 29Formation30

12012012010 pixels10 pixelsEuler Hill Reference Frame31

Non-dimensionalized equations of motion for the perturbing force in the local Hill frame:

Solution for Force Free Motion and Impulse Conditions:Euler Hill Approximation32Euler Hill Approximation33

Formation Deployment34

120120120

Cube Sate Delta-V Calculation35Thruster SpecsPropellant volume = 95 cm3Propellant density = 0.556 g/cm3Isp = 65 secMaximum Mass (full Cube Sat) = 4 kgvmax = 8.411 m/s

Station KeepingPerturbations for LEO orbitsAtmospheric DragJ2 EffectOnly J2 Effect considered for station keeping calculationsOrbit eccentricity determined by Maximum Radial Component of Formation Width divided by Nominal Orbit RadiusDelta-Vs for 1 year is 0.0496km/sm/m = .00036%36Deployment Vehicle Delta-V CalculationabGNC & CommunicationsTechincal Group LeadJosh Jennings

Team MembersChris CederbergKen CundiffNicholas GawloskiKristina LoftinMichael Young38GNC Control PackageBlue Canyon XACTComplete GNC PackageReaction WheelsTorque RodsSun SensorsStar TrackerIMUMagnetometerGPSPointing Accuracy: 0.007 $110,000 (with GPS)Whole system not flight tested, just the star trackerBlue Canyon XACT39

IssuesVery expensive; propagated over many craftNeed extremely high pointing accuracyConclusionsXACT meets minimum specificationsWill use XACT for GNCGNC Control Package40

Control Response from SimulinkPID Control using Reaction Wheels in XACTRotated to some arbitrary anglesShows ability of XACT Reaction Wheels to change orientation of 3U cubesatDoes not factor in environmental disturbancesGNC Dynamics Control Verification41TelecommunicationsDownlink: Mother Sat to Earth S-Band Transmitter w/ patch antennaGain: 8 dBiBeamwidth: 602.4 - 2.483 GHz1 Mbps Link Margin: 6.1 dBPowerTransmitting Power 2WSystem Losses 2 dBAntana Gain 8 dBEIRP (Effective Isotropic Radiaded Power)9 dBFrequency (S-Band)2.44 GHzFree Space Loss (max distance 1944 km)166 dBAtm/Prec Losses 1 dBSystem Noise Temperature 26 dbkTotal Propagation Loss193 dBReceive Antenna Gain 31.5 dBSystem losses 2 dBEb/No14.1 dBMinumum for 10e-5 BER9.6 dBMargin4.5 dB42

42Uplink: Earth to Mother SatISIS VHF downlink / UHF uplink Full Duplex Transceiver FrequencyUHF: 400-450 MHz9600 bpsDeployable UHF/VHF antennaUHF Gain: -6 dBi

Telecommunications43Link BudgetUplinkTransmitting Power 5WSystem Losses 3dBAntana Gain 16.4dBEIRP (Effective Isotropic Radiaded Power)20.4dBFrequency (S-Band)425MHzData Rate9600kbpsFree Space Loss (max distance 1944 km)166dBAtm/Prec Losses 1dBSystem Noise Temperature 26dbkTotal Propagation Loss193dBReceive Antenna Gain -6dBSystem losses 2dBEb/No24.3dBMinumum for 10e-5 BER9.6dBMargin14.7dB44TelecommunicationCrosslink: Eye Sat to Mother SatISIS UHF downlink / VHF uplink Full Duplex Transceiver FrequencyUHF: 400-450 MHz9600 bpsVFH: 130-160 MHz1200 bpsDeployable UHF/VHF antennaUHF Gain: -6 dBiVHF Gain: -5 dBi

45Link Budget Cross LinkUHF/VHFCrosslink VHFTransmitting Power 500mWSystem Losses 3dBAntana Gain -5dBEIRP (Effective Isotropic Radiaded Power)-11dBFrequency (VHF)425MHzData Rate9600kbpsFree Space Loss (max distance 5 km)98dBAtm/Prec Losses 0dBSystem Noise Temperature 26dbkTotal Propagation Loss124dBReceive Antenna Gain -5dBSystem losses 2dBEb/No52.8dBMinumum for 10e-5 BER9.6dBMargin43.2dBCrosslink UHFTransmitting Power 500mWSystem Losses 3dBAntana Gain -6dBEIRP (Effective Isotropic Radiaded Power)-12dBFrequency (UHF)425MHzData Rate9600kbpsFree Space Loss (max distance 5 km)98dBAtm/Prec Losses 0dBSystem Noise Temperature 26dbkTotal Propagation Loss124dBReceive Antenna Gain -6dBSystem losses 2dBEb/No43.8dBMinumum for 10e-5 BER9.6dBMargin34.2dB46PropulsionTechnical Group LeadEvan Siracki

Team MembersFernando AguileraJohn AlbersRandall ReamsNicholas MatcekJames Kim47Launch VehiclePegasus XL443 kg payload into LEOLaunch cost - $11 millionDiameter - 1.27 m88% success rate100% success rate since 1996.Allows for direct insertion into orbit

48CubeSat PropulsionMost of the cubesats currently in orbit do not have an active propulsion system. However, in order to keep our cubesats in formation small amounts of thrust are required to compensate for translational perturbations. This is necessary to allow for formation flying.

49VACCO Micro-ThrusterVACCO/JPL Butane Micro-ThrusterCold gas thruster5 multi-directional thrusters, ideal for translational perturbation correctionsLow power consumption: 100mW-4W peakLow mass: 509g (50 g of propellant)Low Isp: 70sVacuum tested but not flight tested

50Power & ThermalTechnical Group LeadHaylie Peterson

Team MembersJeff HamJonathan LagroneLisa MaloneEvan MarcotteMichael Wilkinson51Power EstimateTechnical TeamsPower Required (Optic)Power Required (Communication)Propulsion2 watts2 wattsGNC2 watts2 wattsTelecommunications2 watts7 wattsOptics2.5 watts2.5 wattsOptic Boom15 watts0 wattsCPU0.3 watts0.3 wattsTotal Power24.3 watts14.3 wattsAll calculations based on peak power required52BP4 Battery Pack

Easily fits in CubeSatProvides enough power for internal componentsBattery is rated for 30 W maximum.

53-Easily fits in CubeSat-provides enough power for internal components-Battery is rated for 43.68 W-h. Using a general set of CubeSat Components, the Power required is roughly 21 W-h. Therefore, the battery provides enough power for the CubeSat.

53P31US Power Module

6 User-controlled output controlsPhotovoltaic power conversion up to 30 W Can accommodate panels with up to 7 solar cells in a string54-6 User-Controlled Output Controls.-Photovoltaic Power Conversion up to 30 W. - for panels with up to 7 solar cells in a string.

54CPU-NanoMind A712D

ARM7 processor - 8-40 Mhz RTC - real time clock w/backup power keeps time 30-60 minutes without external powerMicroSD socket for up to 2GB storage On-board magnetometer 6x sun-sensor inputs 55P110 Series GaAs Solar Panels$2800/panelGallium ArsenideTends to have less noise than silicon (especially at high frequencies)Emit light efficientlyHighly resistive (due to wide bandgap)High-cost, high-efficiency Specifications per panel30% efficiencyUp to 2.4 Watts absorption per orbit Operational temperature: -40 C to +85 CCompatibility: GomSpace NanoPower P31US power supply

56-The choice of Solar Panel is Gallium Arsenide instead of Silicon. This is because the GaAs Solar Panels are more efficient, and can absorb more power in an orbit.

56THERMAL PROTECTIONMULTI-LAYER INSULATION

For thermal protection of the internal components of the CubeSat, we chose Multi-Layer Insulation with Kapton film for the outer layer and multiple layers of, a Dacron web, a Mylar film, and Deposited Aluminum in series for 2-35 layers. With the thermal protection the maximum temperature inside the CubeSat is 355.9 K and minimum temperature 273.3 K, assuming the heat given off by internal components is 15 W. Max Thickness = 1mm57-For Thermal Protection of the internal components of the CubeSat, we chose Multi-Layer Insulation with Kapton film for the outer layer and multiple layers of, a Dacron web, a Mylar film, and Deposited Aluminum in series for 2-35 layers. -With the Thermal Protection the Maximum temperature inside the CubeSat is 355.9 K and Minimum Temperature 273.3 K, assuming the heat given off by internal components is 20 W.

57Risk AssessmentSolar panels could get hit by space debris and/or possibly failModerate-low (0.4)To mitigate this there is some redundancy because there are several solar panels on the cubeSat. Therefore, if one or two soalr panels fail enough power can still be provided to the cubeSatTear in the MLI could cause internal temperatures to be higher or lower than expectedLow-High (0.3)Using a thicker MLI would help prevent this if debris were to get through the solar panelsIf power module fails then the battery pack could become overcharged, cause the batteries to heat up, and lower the battery life.Low-High (0.3)Some power controls could be done by the CPU in case of an emergency failure of the power module.

58Structures GroupTechnical Group LeadTanner Black

Team MembersVeronica BettsPaden Coats David KosteckaPatrick WhalenTaylor Yeary59Major Structural DecisionsOptics SatelliteOptics SatelliteMaterial6000 series AluminumWeight