Will JUICE flyby an asteroid during its cruise?

     

    The discussion took place with the Juice scientists and the ESA project in the second half of 2023. Given the excellent Juice launch performances, it was legitimate to discuss a possible asteroid flyby during the cruise phase.

    Even if an asteroid flyby is not an immediate milestone (most likely to take place in 2029), a decision was preferably to be made early for two reasons: first, such a flyby is not in the mission baseline and would need a significant amount of preparation; secondly, the next update of the nominal trajectory requires the best knowledge of the propellant status to study various options.

    Preliminary mission analysis and publications from the scientific community gave some indication of the possible flyby opportunities. 

    An asteroid flyby was obviously of strong interest for the remote sensing instrument teams (MAJIS and JANUS). A compelling target was the asteroid 223 Rosa. However, preliminary analysis indicated that its flyby would require significant propellant usage, which is equivalent to the manoeuvre to reach the 200 km orbit at Ganymede. Much smaller objects requiring less propellant usage (10 m/s) were identified, but not characterized in details yet.

    Eventually, the scientists and the project decided to not implement an asteroid flyby, to keep all propellant margins to improve the science return of the nominal mission, for a potential mission extension and for safety.


    ​​​​Olivier Witasse, 11 June 2024