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Spacecraft Anomalies: an Update

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Spacecraft Anomalies: an Update Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Spacecraft Anomalies: An Update Andreas Aste Department of Physics University of Basel Basel, May 15, 2008 Spacecraft Anomalies: An Update 1 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Overview 1 Interplanetary Spaceflight Swing-by Deep Space Network Spacecraft Navigation 2 Prehistory The Pioneer Anomaly 3 Flyby Anomalies in EGAs First Observation Flyby data set 4 Search for Explanations Origin of the Flyby Anomaly Origin of the Pioneer Anomaly 5 Outlook Spacecraft Anomalies: An Update 2 / 29 Main advantages Higher velocities → distant targets can be reached Saves fuel, time and expense Easy access to orbits far from the ecliptic Can be repeated several times Trajectories of Pioneer 10 & 11 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Swing-By Swing-by (or flyby, slingshot, gravity assist): A method in interplanetary spaceflight to alter the path (and the speed) of a spacecraft by the use of a planet or other heavy celestial body. First swing-by-maneuver (1970): Rescue of the Apollo 13 crew. First planned gravity assist (1973): Deceleration of Mariner 10 by Venus in order to reach a stable orbit around Mercury. Spacecraft Anomalies: An Update 3 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Swing-By Swing-by (or flyby, slingshot, gravity assist): A method in interplanetary spaceflight to alter the path (and the speed) of a spacecraft by the use of a planet or other heavy celestial body. First swing-by-maneuver (1970): Rescue of the Apollo 13 crew. First planned gravity assist (1973): Deceleration of Mariner 10 by Venus in order to reach a stable orbit around Mercury. Main advantages Higher velocities → distant targets can be reached Saves fuel, time and expense Easy access to orbits far from the ecliptic Can be repeated several times Trajectories of Pioneer 10 & 11 Spacecraft Anomalies: An Update 3 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Pioneer Trajectories Spacecraft Anomalies: An Update 4 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Deep Space Network: Spacecraft Navigation DSN Logo DSN: International network of communication facilities (large radio antennas) for the support of interplanetary spacecraft missions & radio- und radar astronomy. 3 facilities (distance ∼ 120 degrees) Goldstone DSN Complex, Mojave Desert, California, USA Madrid DSN Complex, Robledo (Madrid), Spain Canberra DSN Complex, Tidbinbilla (Canberra), Australia Goldstone, California Spacecraft Anomalies: An Update 5 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Deep Space Network Spacecraft Anomalies: An Update 6 / 29 19 0 221 −∆νE νE −νE → vP = 461 , mit ∆νE = ν , 221 +∆νE E 00 00 νE −νE 1 νE −νE bzw. vP = 00 c ' 2 ν c without frequency turnaround ratio( hard coded). νE +νE E Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Spacecraft Navigation Main method for measuring the longitudinal velocity of spacecraft: DOPPLER EFFECT Basic strategy (Pioneer) DSN reference frequency: νE q c−vP Receive frequency: νR = νE c+vP Response signal from Pioneer: 0 νR = (240/221)νR 0 q c−vP DSN receive frequency: ν = νR E c+vP Spacecraft Anomalies: An Update 7 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Spacecraft Navigation Main method for measuring the longitudinal velocity of spacecraft: DOPPLER EFFECT Basic strategy (Pioneer) DSN reference frequency: νE q c−vP Receive frequency: νR = νE c+vP Response signal from Pioneer: 0 νR = (240/221)νR 0 q c−vP DSN receive frequency: ν = νR E c+vP 19 0 221 −∆νE νE −νE → vP = 461 , mit ∆νE = ν , 221 +∆νE E 00 00 νE −νE 1 νE −νE bzw. vP = 00 c ' 2 ν c without frequency turnaround ratio( hard coded). νE +νE E Spacecraft Anomalies: An Update 7 / 29 Pioneer 10: Launch March 2, 1972 / Jupiter flyby Dec 3, 1973 → hyperbolic orbit, radio contact till Feb 2003. Pioneer 11: Launch April 5, 1973 / Jupiter flyby Dec 2, 1974 / Saturn flyby Sept 1, 1979 → hyperbolic orbit, contact till Nov 1995. Pioneer anomaly −10 2 αPioneer = −(8.74 ± 1.33) · 10 m/s Comments Anomalies of Pioneer 10/11 coincide within a range of ∼ 3%. −5 2 aSun(20 AU) = 1.48 · 10 m/s . −10 2 −10 2 Remains a mystery... cH0 ' 6.8 · 10 m/s , a0(MOND) ' 1.2 · 10 m/s . Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Mysterious Deceleration of the Pioneer Probes John Anderson 1 (Jet propulsion laboratory, Pasadena, Kalifornien): Anomalous deceleration of Pioneer spacecraft since ∼ 1980 towards the sun (or the earth ?). Reliable Doppler telemetry data now available for ∼ 1973-2002 (Pioneer 10), 1974-1990 (Pioneer 11). 1 J. D. Anderson, July 1992 Quarterly Report to NASA Spacecraft Anomalies: An Update 8 / 29 Pioneer anomaly −10 2 αPioneer = −(8.74 ± 1.33) · 10 m/s Comments Anomalies of Pioneer 10/11 coincide within a range of ∼ 3%. −5 2 aSun(20 AU) = 1.48 · 10 m/s . −10 2 −10 2 Remains a mystery... cH0 ' 6.8 · 10 m/s , a0(MOND) ' 1.2 · 10 m/s . Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Mysterious Deceleration of the Pioneer Probes John Anderson 1 (Jet propulsion laboratory, Pasadena, Kalifornien): Anomalous deceleration of Pioneer spacecraft since ∼ 1980 towards the sun (or the earth ?). Reliable Doppler telemetry data now available for ∼ 1973-2002 (Pioneer 10), 1974-1990 (Pioneer 11). Pioneer 10: Launch March 2, 1972 / Jupiter flyby Dec 3, 1973 → hyperbolic orbit, radio contact till Feb 2003. Pioneer 11: Launch April 5, 1973 / Jupiter flyby Dec 2, 1974 / Saturn flyby Sept 1, 1979 → hyperbolic orbit, contact till Nov 1995. 1 J. D. Anderson, July 1992 Quarterly Report to NASA Spacecraft Anomalies: An Update 8 / 29 Comments Anomalies of Pioneer 10/11 coincide within a range of ∼ 3%. −5 2 aSun(20 AU) = 1.48 · 10 m/s . −10 2 −10 2 Remains a mystery... cH0 ' 6.8 · 10 m/s , a0(MOND) ' 1.2 · 10 m/s . Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Mysterious Deceleration of the Pioneer Probes John Anderson 1 (Jet propulsion laboratory, Pasadena, Kalifornien): Anomalous deceleration of Pioneer spacecraft since ∼ 1980 towards the sun (or the earth ?). Reliable Doppler telemetry data now available for ∼ 1973-2002 (Pioneer 10), 1974-1990 (Pioneer 11). Pioneer 10: Launch March 2, 1972 / Jupiter flyby Dec 3, 1973 → hyperbolic orbit, radio contact till Feb 2003. Pioneer 11: Launch April 5, 1973 / Jupiter flyby Dec 2, 1974 / Saturn flyby Sept 1, 1979 → hyperbolic orbit, contact till Nov 1995. Pioneer anomaly −10 2 αPioneer = −(8.74 ± 1.33) · 10 m/s 1 J. D. Anderson, July 1992 Quarterly Report to NASA Spacecraft Anomalies: An Update 8 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Mysterious Deceleration of the Pioneer Probes John Anderson 1 (Jet propulsion laboratory, Pasadena, Kalifornien): Anomalous deceleration of Pioneer spacecraft since ∼ 1980 towards the sun (or the earth ?). Reliable Doppler telemetry data now available for ∼ 1973-2002 (Pioneer 10), 1974-1990 (Pioneer 11). Pioneer 10: Launch March 2, 1972 / Jupiter flyby Dec 3, 1973 → hyperbolic orbit, radio contact till Feb 2003. Pioneer 11: Launch April 5, 1973 / Jupiter flyby Dec 2, 1974 / Saturn flyby Sept 1, 1979 → hyperbolic orbit, contact till Nov 1995. Pioneer anomaly −10 2 αPioneer = −(8.74 ± 1.33) · 10 m/s Comments Anomalies of Pioneer 10/11 coincide within a range of ∼ 3%. −5 2 aSun(20 AU) = 1.48 · 10 m/s . −10 2 −10 2 Remains a mystery... cH0 ' 6.8 · 10 m/s , a0(MOND) ' 1.2 · 10 m/s . 1 J. D. Anderson, July 1992 Quarterly Report to NASA Spacecraft Anomalies: An Update 8 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Velocity anomaly Spacecraft Anomalies: An Update 9 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Pioneer probe design Weight: 258 kg Energy source: 4 × 40 Watt RGT’s (RGT: Radioisotope thermoelectric generator) Pioneer 10 (final construction stage) Spacecraft Anomalies: An Update 10 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Pioneer design Spacecraft Anomalies: An Update 11 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Plutonium 238 Spacecraft Anomalies: An Update 12 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook RTG Radiation Measurement (Cassini-Huygens) Spacecraft Anomalies: An Update 13 / 29 Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Soviet RTGs Spacecraft Anomalies: An Update 14 / 29 December 1990: J.D. Anderson and other engineers at JPL observe an anomalous velocity increase of space probe GALILEO by∆ v = 3.92 mm/s during an Earth flyby (EGA, earth gravity assist). Further EGAs were investigated in the following: NEAR (’92):∆ v = 13.46 mm/s Cassini (’99):∆ v = −2.0 mm/s Rosetta (’05):∆ v = 1.8 mm/s MESSENGER (’05):∆ v = 0.02 mm/s GALILEO (’92):∆ v = −4.6 mm/s (!) The accuracy of the DSN velocity measurement is ∼ 0.01 mm/s. Equatorial view of the NEAR flyby Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Flyby-Anomaly Spacecraft Anomalies: An Update 15 / 29 Further EGAs were investigated in the following: NEAR (’92):∆ v = 13.46 mm/s Cassini (’99):∆ v = −2.0 mm/s Rosetta (’05):∆ v = 1.8 mm/s MESSENGER (’05):∆ v = 0.02 mm/s GALILEO (’92):∆ v = −4.6 mm/s (!) The accuracy of the DSN velocity measurement is ∼ 0.01 mm/s. Equatorial view of the NEAR flyby Interplanetary Spaceflight Prehistory Flyby Anomalies in EGAs Search for Explanations Outlook Flyby-Anomaly December 1990: J.D.
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