Juno flyby anomaly

  1. nearc

    nearc 46
    Gold Member

    i did a search for juno flyby here and did not find anything, hence this post:

    i've not been able to find any info on the juno flyby anomaly. i know there was a hiccup but did we get any data? was the observed anomaly match the predicted anomaly?
  2. jcsd
  3. Simon Bridge

    Simon Bridge 15,474
    Science Advisor
    Homework Helper
    Gold Member

    You mean this anomaly?


    All kinds of speculation (in lit):

    Certainly there should be data:

    I heard that preliminary results were revealed Dec 11 ... but cannot find documents.
    CONTROL ID: 1799584
    TITLE: Juno Earth Flyby as a Sensitive Detector of Anomalous Orbital-Energy Changes

    AUTHORS (FIRST NAME, LAST NAME): John D Anderson1, James F Jordan1, James K Campbell1, John E Ekelund1, John J Bordi2, Mathew Abrahamson2, Shadan M Ardalan2, Paul F. Thompson2
    INSTITUTIONS (ALL): 1. Retiree, Jet Propulsion Laboratory, Pasadena, CA, United States.
    2. Mission Design & Navigation Section, Jet Propulsion Laboratory, Pasadena, CA, United States.
    ABSTRACT BODY: The fact that unexplained energy changes occur in some Earth flybys, but not all, was reported in 2008 by Anderson et al., Phys. Rev. Lett. 100, 091102. The anomaly is detected by analyzing radio Doppler and ranging data used for space navigation. It is most significant for the closest flybys at altitudes of 539 km for the NEAR spacecraft, 960 km for the first Galileo flyby, and 1956 km for the first Rosetta flyby, with anomalous total changes in the hyperbolic excess velocity at infinity of 13.5 mm/s, 3.9 mm/s and 1.8 mm/s, respectively. There is also a correlation with the amount of asymmetry of the flyby trajectory with respect to the Earth’s equator. As it turns out, the Juno flyby is well suited for another detection of this anomaly, with an altitude of about 500 km, and a declination of the incoming hyperbolic asymptote of 14.6 deg and an outgoing asymptote of 40.4 deg. Further, the control sequence for the spacecraft introduces no significant translational forces for an interval of plus and minus four days of perigee. Based on eight flybys analyzed previously, and an empirical formula given in the 2008 paper, the expected size of the Juno anomaly is about 7 mm/s. The standard error of the measurement is about 0.01 mm/s. We report first results of the data analysis.​
    ... OK but where?!

    The 2008 paper mentioned in the absract I found:
  4. nearc

    nearc 46
    Gold Member

    yep sounds like we still need to wait a bit but thanks
  5. I cannot find the results of this flyby. The Wikipedia page has data for the previous spacecraft flyby, but still nothing for Juno. Does anyone know anything about this?
  6. AlephZero

    AlephZero 7,248
    Science Advisor
    Homework Helper

    The fact that half the authors are listed as "retirees" might have something to do with it, in an age of budget cuts.
  7. Oh, I thought you were talking about the Juno spacecraft when if flew by the Earth :p Anyway, those were interesting texts, Simon. I did learn something today.

  8. I learnt from a private source recently that no anomaly was observed.
  9. berkeman

    Staff: Mentor

    Private sources are not allowed as references at the PF. Can your private source give you a link to a published paper?

    BTW, this thread is a bit old... :smile:
  10. Yes, the thread is old, but there have been a couple of new papers this year. Don't believe NASA/ESA have published the zero results, though.
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