1. Huygens the Planetary Probe under VLBI Magnifier Leonid Gurvits Joint Institute for VLBI in Europe (JIVE) Dwingeloo, The Netherlands

2. 1629-16951625-1712 15.10.1997

3. Huygens entry, descent and landing: 14 Jan 2005

4. 7 July 2005L.Gurvits, EC Press Conference, Dwingeloo, NL4 Radio astronomy segment of the Huygens mission Conceived as an Earth-based support to the Doppler Wind Experiment (DWE) Included  Direct carrier signal detection with DSN-supplied Radio Sci Receiver (real time capability) at Green Bank and Parkes telescopes;  Direct Doppler measurements (JPL-led experiment) at four NRAO VLBA antennas;  Very Long Baseline Interferometry (VLBI) tracking of the probe from 17 radio telescopes (including all six above); Used (only!) the Channel A carrier signal at 2040 MHz only.

5. 7 July 2005L.Gurvits, EC Press Conference, Dwingeloo, NL5 Interferometry: a one-slide tutorial Michelson & Young, 1890s: measurements of stars’ diametres D B Very Long Baseline Interferometry (VLBI): the ultimate angular resolution in astrophysics

6. VLBI tracking of Huygens, 14 January 2005 09:30 UTC16:00 UTC Huygens VLBI tracking obtained: 340 min of carrier signal 26 TByte of data (equivalent of ~6,000 DVD movies)

7. Huygens signal paths Cassini S/C TCXO RUSO TCXO RUSO Channel B Channel A “Channel C” – eavesdropping on Channel A carrier Huygens Data Huygens Receivers Huygens Probe

8. 7 July 2005L.Gurvits, EC Press Conference, Dwingeloo, NL8 Huygens radial velocity measurements Parachute flight dynamics

9. VLBI determination of the Huygens descent trajectory “Doppler interferometry”:~25 km A priori accuracy:~100 km Full VLBI accuracy:~ 1 km

10. VLBI tracking of the Huygens Probe Pushing the limits of high technology Demonstrates high-level synergy between radio astronomy and space exploration Paves the way for future experiments and applications – GPS-like accuracy anywhere in Solar System (Moon, inner and outer planets) Great promise of next generation radio telescopes and arrays (e.g. Square Kilometre Array, SKA)

11. 7 July 2005L.Gurvits, EC Press Conference, Dwingeloo, NL11 Huygens VLBI tracking team (abbreviated) JIVEESA-ESTECNASA-JPLNRAO I.M.AvruchC.. van’t KloosterS.AsmarW.Brisken H.BignallJ.-P.LebretonW.FolknerF.Ghigo A.Brunthaler R.A.PrestonG.Langston R.M.Campbell J.Romney M.A.Garrett L.I.Gurvits, R.Oerlemans S.V.Pogrebenko ASTRONATNFU TasmaniaNICT (CRL) A.R.FoleyJ.Lovell G.Cimo T.Kondo C.Phillips. S.Elingsen U Bonn J. Reynolds B.Reid M.Bird R.Sault. T.Tzioumis NAO ChinaHelsinki UISAS T.An (ShAO)A.MujunenR.Dodson X.Hong(ShAO)J.Ritakari S.Huang(ShAO) D.Jiang(ShAO) X.Liu(UAO) 12 institutes and international organisations in 7 countries