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ULTRA PRECISE VLBI TRACKING OF FUTURE PROBES TO EUROPA AND JUPITER SYSTEM

ULTRA PRECISE VLBI TRACKING OF FUTURE PROBES TO EUROPA AND JUPITER SYSTEM S.V.Pogrebenko 1 , L.I.Gurvits, I.M.Avruch Joint Institute for VLBI in Europe, Dwingeloo, The Netherlands 1 pogrebenko@jive.nl. 4th Workshop on a Future Mission to Europa and the Jupiter System

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ULTRA PRECISE VLBI TRACKING OF FUTURE PROBES TO EUROPA AND JUPITER SYSTEM

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  1. ULTRA PRECISE VLBI TRACKING OF FUTURE PROBES TO EUROPA AND JUPITER SYSTEM S.V.Pogrebenko1,L.I.Gurvits, I.M.Avruch Joint Institute for VLBI in Europe, Dwingeloo, The Netherlands 1 pogrebenko@jive.nl 4th Workshop on a Future Mission to Europa and the Jupiter System October 26-27, 2006, Lindau, Germany.

  2. Basics of phase-referencing VLBI

  3. JIVE experience with Huygens probe’s signal detection using Global VLBI Network 12:30 UTC 3.5 W power in carrier line at 2 GHz 3.5 dBi TX antenna gain, <10-11 probe’s Rb oscillator stability Differential phases on triangle GBT - Mauna Kea - Mopra Phase noise ~0.5 radian for 10s integration translates into ~1 km spatial accuracy at Titan distance Signal detections at 8.2 AU distance with 100 m (GBT), 64 m (Parkes) and 25-20 m (VLBA and ATNF)antennas

  4. Cassini Detection, carrier wave as seen by 10 VLBI stations, Phase tracking accuracy ~ 1 milliradian in 1 second, Practice run on October 2004

  5. Triangulation… Just as Archimedes did it But now we do it In a curved space-time Of General Relativity

  6. Plus phase referencing..

  7. After phase referencing – Differential Doppler shifts (mHz) for 6 25-m antennas With respect to GBT (left) and differential phases (radians) on these baselines And residual phases on detections, rms < 0.5 radian

  8. And “FIRST (PRELIMINARY) TRAJECTORY”, fit with independently reconstructed DTWG trajectory based on radial Doppler, pressure sensor and altimeter

  9. On behalf of the project team: L.Gurvits, JIVE, NL S.Pogrebenko, JIVE, NL I.Avruch, JIVE, NL R.Campbell, JIVE, NL R.Oerlemans, JIVE, NL A.Szomoru, JIVE,NL A.Mujunen, HUT/MRO, FI J.Ritacari, HUT/MRO, FI J.Wagner, HUT/MRO, FI G.Maccaferri, INAF/IRA, IT S.Montebugnoli, INAF/IRA, IT A.Foley, ASTRON/WSRT, NL B.Foing, ESA/ESTEC, NL O.Camino, ESA/ESTEC, NL T.Morley, ESA/ESOC, DE L.Petrov, NASA/GSFC, USA ESA spacecraft Smart 1 was observed by EVN stations Mc, Mh, and Wb on May 25 2006 at S-band as a test run in a frame work of EH019 project in preparation for other interesting events. I’m happy to present here the sneak Preview of some preliminary results of Smt25 VLBI test run. S.Pogrebenko, JIVE With special thanks to K.Stuurwold (ASTRON), for bringing up the Huygens computer, And A.Whitney and J.Ball (MIT/Haystack) for their support of Mk5A software There were many Firsts out there recently: First fringes, First lights, First Images. But now First VLBI Fun with the Smart One

  10. Dynamic spectra taken by Medicina (left) and Metsähovi (right) stations during the spacecraft’s egress from an occultation Voltage (Re and Im in 4 Hz band) and power for stations Mc and Mh. Note, that actual change of a power level from diffracted to direct beams is tens of thousand times … Check these “mouse tails” at the bottom of the main detections..

  11. Strain plot – short time variation of the distance Between Earth and S/C, detected feature at 21.1 Hz with a strain 3.2*10-14 corresponds to distance oscillations with an amplitude of 10 micron The best explanation : vibration of S/C structure

  12. Projections for VLBI spatial accuracy at S, X and Ka bands for Saturnian and Jovian systems Signal strength at Earth (W/m2) for TX power PTX, antenna gain GTX and distance R SNR for radio telescope with diameter D, efficiency Aeff, system temperature Tsys and spectral resolution dF, (dF =1 / tint) SNR for a baseline between stations 1 and 2 Differential phase accuracy (radians) Potential spatial accuracy (meters) In 1 hour semi-coherent integration time, 1-3 W semi-isotropic TX power and adequate TX LO stability: S-band (2 GHz) < 100 meters X-band (8 GHz) < 10 meters Ka-band (30 GHz) < 1 meter European & Global VLBI Network

  13. Potential projects More than an order of magnitude improvement of the Jovian system celestial mechanics model Multiple landers + orbiter: plate tectonics of geologically active bodies in Jovian system, Tidal deformation of Jovian satellites Multiple landers + orbiters: Tomography of electron content of near-Jupiter plasma S.V.Pogrebenko1, L.I.Gurvits, I.M.Avruch Joint Institute for VLBI in Europe, Dwingeloo, The Netherlands 1 pogrebenko@jive.nl European & Global VLBI Network

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