Transiting Exoplanet Survey Satellite Transiting Exoplanet .
https://ntrs.nasa.gov/search.jsp?R 20180007434 2020-03-03T14:44:25 00:00ZTransiting Exoplanet Survey SatelliteTransiting Exoplanet Survey Satellite (TESS)Flight Dynamics CommissioningResults and ExperiencesJoel J. K. ParkerRyan L. LeboisStephen LutzCraig NickelKevin FerrantAdam MichaelsAugust 22, 2018NASA Goddard Space Flight CenterL3 Applied Defense SolutionsL3 Applied Defense SolutionsL3 Applied Defense SolutionsOmitron, Inc.Omitron, Inc.
Contents Mission OverviewFlight Dynamics Ground SystemTESS Commissioning LaunchPhasing LoopsLunar Flyby & Transfer OrbitPAM & Extended Mission DesignCommissioning ResultsOrbit DeterminationConclusionsTESS Post Launch Assessment Review2
Mission Overview—Science Goals Primary Goal: Discover Transiting Earths andSuper-Earths Orbiting Bright, Nearby Stars Discover the “Best” 1000 Small Exoplanets Rocky planets & water worldsHabitable planets“Best” means “readily characterizable” Bright Host Stars Measurable Mass & Atmospheric PropertiesUnique lunar-resonant mission orbit provideslong view periods without station-keepingLarge-Area Survey of Bright StarsF, G, K dwarfs: 4 to 12 magnitude M dwarfs known within 60 parsecs “All sky” observations in 2 years All stars observed 20 days Ecliptic poles observed 1 year(JWST Continuous Viewing Zone) TESS SE EPR, 14-15 May 20153
Mission Overview—Trajectory Design Overall mission design:3.5 phasing loops lunar flyby transfer orbit mission orbitMission orbit features 2:1 lunar resonance (“P/2”), or 13.67 d mean orbit periodTESS Post Launch Assessment Review4
Mission Overview—Commissioning Overall commissioning is 60d process6 planned maneuvers 5 optional/backup maneuversTESS Post Launch Assessment Review5
Mission Overview—Spacecraft Northrop Grumman LEOStar-2/750 busPropulsion: 2x S-band omnidirectional antennas1x Ka-band high-gain antenna (HGA)Attitude Control: 1x 22N ΔV reaction engine assembly (REA)4x 4.5N REA for attitude controlCommunications: 4x reaction wheel assemblies (RWAs), 2x startracker assemblies, 10x coarse sun sensorsKeep-out zones associated with all sensorsInstrument: 4x camera assemblies30 by 50 rectangular keep-out zoneTESS Post Launch Assessment Review6
Mission Overview—NavigationMeasurement Summary by AltitudeSeparation through PAM7060Altitude (Re)5040302010022 Sun1 Tue8 TueApr 201815 Tue 1 FriTime (UTCG)Tess Tracking 22 TueTess No TrackingNavigation support provided by NASA Deep Space Network (DSN) and Space Network(SN)SN post-separation acquisition at 1 minHandover to DSN by 1.5 hrNear-continuous tracking through first phasing loop, then scheduled to cover maneuversand meet OD accuracy requirementsPost-launch SN support scheduled around perigee maneuvers onlyTESS Post Launch Assessment Review7
Flight Dynamics Ground System TESS Flight DynamicsGround System: FDF responsibilities: Facility/infrastructureDSN/SN data interfacesIOD external verificationFDS responsibilities: NASA Flight DynamicsFacility (FDF)TESS Flight Dynamics SystemManeuver planningOrbit determinationProduct generationManeuver reconstruction/calibrationSoftware utilized:SoftwareL3 ADS Flight Dynamics System (FDS)NASA General Mission Analysis Tool (GMAT)AGI Orbit Determination Tool Kit (ODTK)Goddard Trajectory Determination System (GTDS)SPICE ToolkitAGI Systems Tool Kit (STK)MATLABUseProcedure Execution, Data ManagementManeuver Planning, Ephemeris GenerationPrimary Orbit DeterminationBackup Orbit DeterminationDSN Acquisition GenerationAnalysis, QA, VisualizationsAnalysis, PlottingTESS Post Launch Assessment Review8
Launch PerformanceLaunch Date: April 18th 2018Vehicle: SpaceX Falcon 9Location: Cape CanaveralAir Force Station, SLC-40EventLiftoffActual (UTC)Delta (s)22:51:30.498 -0.502Separation 23:41:03.177 2.177Element*Pre-Launch BETODDeltaApogee Altitude [km]268,622.397269,330.228707.831Perigee Altitude [km]248.456248.755Inclination [deg]Argument of Perigee[deg]29.563228.1113σ Requirement Sigma 20,0000.110.299 250.0429.5790.016 0.10.48228.088-0.023 0.3-0.23*All elements at epoch: 18 Apr 2018 23:45:30.666 UTCTESS Post Launch Assessment Review9
Phasing Loops All burns nominal A2M waived asunnecessary(A2M)A1M(flyby) Performance error P1MP2MPAMP3M 7% worstcase 1% for majormaneuversCalibratedΔV (m/s)PerformanceError (%)MeanPointingError (deg)ManeuverEpochDur.(sec)A1M22 Apr 2018 01:59:06.628503.915-3.339.6P1M25 Apr 2018 05:36:42.05344932.265-0.930.6P2M04 May 2018 08:05:46.65070.430-6.620.4P3M13 May 2018 11:37:48.648291.862 2.871.6PAM30 May 2018 01:20:23.14992353.409-0.110.7TESS Post Launch Assessment Review10
Maneuver Performance Maneuver performance error trends with duration Shorter duration correlated with underperformanceTrend explained as an artifact of thermal ramp-up of propulsion systemAnalysis through P2M was used to predict likely performance of P3M flybytargeting maneuver Maneuver thrust scaled by 95% during P3M planning to better target desired flybyTESS Post Launch Assessment Review11
Lunar Flyby & Transfer Orbit Lunar flyby: 17 May 2018Performance asexpected:EventTime (UTC)Lunar Altitude (km)Expected06:33:068183 kmObserved06:34:368254 kmDelta90 s71 kmElementPre-flyby Post-flybyPerigee Radius (RE)1.1416.53Apogee Radius (RE)56.2372.61INC(deg) Transfer orbit:29.336.6Achieved apogeeradius:RAAN (deg)37286 70.25 RE Achieved perigeeradius:16.54 RE230356AOP (deg)TESS Post Launch Assessment Review12
PAM Design & Extended Mission Design PAM: Period Adjust Maneuver Goal: Lower apogee to achieve 2:1 lunar resonance (approx. 13.67 dayorbit period)Secondary objectives:Improve long-term eclipse profile Maintain long-term orbit stability PAM was fine-tuned via parametric scanning process Long-term extended-mission analysis performed to 18–25 years ofmission life (to extent of prediction capability)PAM start epoch fixes eclipse “trade space”PAM duration chooses specific eclipse profile within trade spaceTwo major tools: Eclipse profile plots (a.k.a. “Napolean plots”)Mean orbit period plotsTESS Post Launch Assessment Review13
Extended Mission Eclipse Profile Plot is associated with a PAM start epoch chosen by targeter.Each row shows eclipses over time for a trajectory associated with agiven PAM duration (scale factor from nominal).Selected PAM duration was chosen to avoid 3 hr eclipses in 2021and 4 hr eclipses in 2027 Selected duration 97% of nominal (923 s, 53.6 m/s)Associated initial mission orbit period 13.72 daysTESS Post Launch Assessment Review14
Extended Mission StabilityEach series 1 PAMscaling value25-yearmean(above) isrepresentedas one value(below)Meanshould beapprox.13.67 daysto indicatestabilityselected 0.97TESS Post Launch Assessment Review15
Commissioning Results PAM execution nominal;achieved long-term eclipseprofile shows no eclipses 3 hr durationAchieved initialorbit period 13.73 dLong-term stability andperigee/apogee altitudepredictions meet expectationsAll commissioning mission requirements were met:RequirementOrbit PeriodMaximum Perigee RadiusMaximum Apogee RadiusMaximum Total ΔVMaximum Single Maneuver ΔVMaximum Commissioning DurationEclipsesOrbit Determination Position AccuracyOrbit Determination Velocity AccuracyValue13.67 days (2:1 lunarresonance) 22 RE 90 RE 215 m/s 95 m/s 2 months 16 eclipses, 4 hoursduration each (umbra ½penumbra) 6 km per axis 7% of maneuver magnitudeTESS Post Launch Assessment ReviewAchievedAchieved (orbit period oscillatesabout 13.67 days)18.70 RE70.25 RE91.19 m/s53.41 m/s54.87 days10 eclipses in primary mission;longest 2.5 hrAchieved throughout commissioningAchieved throughout commissioning16
Orbit Determination Orbit determination was performed throughout commissioningSoftware: AGI Orbit Determination Toolkit (ODTK)DSN measurement types processed: TCP, Sequential RangeTDRS 5L Doppler measurements were available, but not used in final solutionMeasurement typesDSN antennasTDRS satellitesDSN TCP, DSN SeqRng, TDRS 5L DopplerDSS24, DSS26, DSS34, DSS36, DSS54, DSS65TDRS-K, TDRS-LTESS Post Launch Assessment Review17
Orbit Determination Minimal filter tuning wasParameterConstant BiasBias 1σWhite Noise 1σ Bias Half-life [min]required; small injections of DSN TCP-0.080.050.00560DSN SeqRng [m]050.2560process noise were usedSpacecraft Cr1.50.2N/A2880sporadically to preventSpacecraft Cd2.2Not Estimatedcollapse of covarianceSpacecraft5863.4610N/A2880during perigee passesTransponder Delay [ns]Small injections of process noise were used sporadically to prevent collapse of covarianceduring perigee passesOverall 3σ position uncertainty 900 m 450 m through phasing loopsFilter-smoother consistency well-behaved, remains w/in 3σ boundsTESS Post Launch Assessment Review18
Conclusions TESS will perform the first-ever spaceborne all-sky survey ofexoplanets transiting bright stars.TESS launched nominally on 18 Apr 2018, and successfully executeda 60-day flight dynamics commissioning phase.All maneuvers executed nominally or were waived as unnecessary.All commissioning and primary mission requirements were met andare expected to continue to be met for 18 yearsMission ”firsts”:First mission designed for resonant orbit in the primary mission Use of innovative techniques for fine-tuning final maneuver for long-termcharacteristics First application of NASA’s open-source GMAT in a primary role TESS is now on-orbit, and continues instrument commissioningactivities in advance of first science return.TESS Post Launch Assessment Review19
NASA General Mission Analysis Tool (GMAT) Maneuver Planning, Ephemeris Generation AGI Orbit Determination Tool Kit (ODTK) Primary Orbit Determination Goddard Trajectory Determination System (GTDS) Backup Orbit Determination SPICE Toolkit DSN Acquisition Generation AGI Systems Tool Kit (STK) Analysis, QA, Visualizations MATLAB Analysis, Plotting
Optical Design of Camera for TESS - 10 6/7/15 Hybrid Petzval design with no vignetting proved to have the best light gathering under the volume and weight constrictions Two aspheric surfaces improve the r.m.s. spot size by 60% compared with the non-aspheric design. Internal short wave rejection filter coating successfully replaced
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NASA Exoplanet Exploration Program Dr. Gary Blackwood, Program Manager Jet Propulsion Lab
This paper will cover the details on the optical design of the cameras including their expected performance. Also included are the stray light performance for baffles and the optical filter coating, enabling the optical system to meet the
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