Tracking Juno: Here it comes and there it goes

A pair of photos of ESA’s Malargue station that perfectly illustrate how the Agency’s tracking efforts progressed last night.

At left, the huge 35m dish antenna is pointing more or less straight up as Juno approached Earth high above Argentina. Of course, Earth rotates, so the antenna had to be continuously tracked down and rotated.

At right, finally, as Juno dipped out of line-of-sight below the horizon, the station lost contact with the spacecraft with the antenna pointed low toward the East.

The craft continued en route to make closest approach above S. Africa a few minutes after the right-hand image was taken.

ESA Malargüe station as Juno zooms in to view

ESA Malargüe station pointing almost vertically up as NASA’s Juno spacecraft approaches from deep space over Argentina on 9 October 2013. Credit: ESA

ESA Malargüe station as Juno zooms out of view Credit: ESA

ESA Malargüe station as Juno zooms out of view Credit: ESA



  • Do you have any idea when the amount of the anomalous acceleration will be released?

    • Daniel says:

      Hi Kimmo: No, we at ESA do not. All our recorded tracking data have been passed to NASA. They’re in the lead for this particular assessment (just like we were for our Rosetta ESB). In fact, we couldn’t do the analysis unless we had other spacecraft-specific data that only the operators have. So we, just like you, will have to wait!

      • Okey, thanks! I made a prediction for the anomaly. ~0.5556 mm/s at perigee and total little less than 1.111 mm/s. After perigee Juno went into safe mode which might have changed the attitude and spin frequency of Juno (therefore last half of the flyby won’t generate as large speed increase as the first half).

        • It also might be that the speed increase is at perigee that 1.111 mm/s. My model ain’t totally ready yet… Any idea if Juno’s spin frequency was changed to 1 rpm due to safe mode? That will effect the later half of the flyby and generated anomalous speed increase.

  • I finished my model and made a new press release concerning the anomalous speed increase.

  • Do you know how long it usually takes to release Earth flyby anomalous acceleration results? Measurements are done seven days before and after a flyby.

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