Electrodynamic Tether at Jupiter—I: Capture Operation and Constraints

Tethered spacecraft missions to the Jovian system suit the use of electrodynamic tethers because: 1) magnetic stresses are 100 times greater than at the Earth; 2) the stationary orbit is one-third the relative distance for Earth; and 3) moon Io is a nearby giant plasma source. The (bare) tether is a reinforced aluminum foil with tens of kilometer length L and a fraction of millimeter thickness h, which collects electrons as an efficient Langmuir probe and can tap Jupiter's rotational energy for both propulsion and power. In this paper, the critical capture operation is explicitly formulated in terms of orbit geometry and established magnetic and thermal plasma models. The design parameters L and h and capture perijove radius r p face opposite criteria independent of tape width. Efficient capture requires a low r p and a high L 3/2/h ratio. However, combined bounds on tether bowing and tether tensile stress, arising from a spin made necessary by the low Jovian gravity gradient, require a high r p and a low L 5/2/h ratio. Bounds on tether temperature again require a high r p and a low L 3/8/(tether emissivity)1/4 ratio. Optimal design values are discussed.

...The capture operation was analyzed in previous work [2]...
...With both cross-sectional area and perimeter of a thin tape of given thickness being proportional to its width w, no characteristic dimensionless number involves w; the SC mass will just scale up with w in a range allowing from about 0.2 to 5 t. We will set w =3 cm wherever choosing a definite mass is convenient, with mt being 202 kg and MSC being about 650 kg [2]...
...following elliptical orbits only depends on eccentricity e through a standard formula in orbital mechanics [2]...
...Calculating the drag work Wd,e follows closely the analysis for capture work in [2]...
...The current iav is a universal function iav( ˆ L) given in [2]...
...In general, iav is found to be a function of the ratio Iav(OML)/σcwhEm ≡ 3 ˆ L 3/2 /10, with ˆ L as given in [2]...
...For the moon tour in Section V, which does not involve small e values, we may therefore use Se = S1(rp/RJ , Λ, 1) throughout in (11); S1 is the function called S(rp/RJ , Λ) in [2]...
...The function Σ, as given in [2], is used in Fig. 2 to represent the eccentricity decrement versus perijove radius for the reference 50-km-long 0.05-mm-thick tape, and two values of the mass ratio roughly corresponding to decrements Δe =1 − eh and 2(1 − eh)...
...During capture, a very large amount of energy would be taken from the orbital motion of the SC into the tether electric circuit, and ultimately transformed into thermal energy of the tether, to be radiated away, as discussed in [2]...

Keywords (3)

Electrodynamic Tether at Jupiter—I: Capture Operation and Constraints,10.1109/TPS.2008.2002580,IEEE Transactions on Plasma Science,Juan R. Sanmartin,M

Citation Context (1)

Juan R. Sanmartin, et al. Electrodynamic Tether at Jupiter—II: Fast Moon Tour After Capture

References (15)

Electrodynamic Tether at Jupiter—II: Fast Moon Tour After Capture (Citations: 4)

The Jupitor icy moons orbiter project: The scientific rationale (Citations: 2)

Electrodynamic Tether Propulsion and Power Generation at Jupiter (Citations: 2)

Empirical model of the Io plasma torus: Voyager measurements (Citations: 175)

Plasma turbulence enhanced current collection: Results from the plasma motor generator electrodynamic tether flight (Citations: 6)

Citations (5)

The radiation impedance of electrodynamic tethers in a polar Jovian orbit

Electrodynamic Tether Applications and Constraints

Lorentz-Augmented Jovian Orbit Insertion (Citations: 7)

Electrodynamic Tether at Jupiter—II: Fast Moon Tour After Capture (Citations: 4)

Jupiter Power Generation with Electrodynamic Tethers at Constant Orbital Energy (Citations: 3)


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