One EURO for Uranus: the Elliptical Uranian Relativity Orbiter mission

Abstract

Recent years have seen increasing interest in sending a mission to Uranus, visited so far only by Voyager 2 in 1986. EURO (Elliptical Uranian Relativity Orbiter) is a preliminary mission concept investigating the possibility of dynamically measuring the planet's angular momentum by means of the Lense-Thirring effect affecting a putative Uranian orbiter. It is possible, at least in principle, to separate the relativistic precessions of the orbital inclination to the Celestial Equator and of the longitude of the ascending node of the spacecraft from its classical rates of the pericentre induced by the multipoles of the planet's gravity field by adopting an appropriate orbital configuration. For a wide and elliptical $2000\times 100000\mathrm{km}$ orbit, the gravitomagnetic signatures amount to tens of milliarcseconds per year, while, for a suitable choice of the initial conditions, the peak-to-peak amplitude of the range-rate shift can reach the level of $\simeq 1.5\times 10^{-3}$ millimetre per second in a single pericentre passage of a few hours. By lowering the apocentre height to $10000\mathrm{km}$, the Lense-Thirring precessions are enhanced to the level of hundreds of milliarcseconds per year. The uncertainties in the orientation of the planetary spin axis and in the inclination are major sources of systematic bias; it turns out that they should be determined with accuracies as good as $\simeq 0.1-1$ and $\simeq 1-10$ milliarcseconds, respectively.

LaTex2e, 40 pages, 7 figures, no tables. Minor revisions. Accepted in Monthly Notices of the Royal Astronomical Society

References in corpus (7)

• Gravity Probe B: Final Results of a Space Experiment to Test General Relativity
• General Relativity and Cosmology: Unsolved Questions and Future Directions
• Phenomenology of the Lense-Thirring effect in the Solar System
• Lense-Thirring frame dragging induced by a fast-rotating white dwarf in a binary pulsar system
• Constraining the dense matter equation-of-state with radio pulsars
• Empirical Structure Models of Uranus and Neptune
• Tilting Uranus via the migration of an ancient satellite

Cited by in corpus (4)

• Kilometer-precise (UII) Umbriel physical properties from the multichord stellar occultation on 2020 September 21
• Prospects for localising Planet 9 with a future Uranus mission
• A Search for Planet Nine with IRAS and AKARI Data
• Post-Newtonian orbital effects induced by the mass quadrupole and spin octupole moments of an axisymmetric body