Electric sail-based displaced orbits with a refined thrust model

Abstract

This paper analyzes the performance of an electric solar wind sail for generating and maintaining a heliocentric circular displaced orbit. Previous research on this subject was based on a simplified mathematical model of the spacecraft thrust. However, recent studies have proposed a more accurate algorithm for evaluating both the modulus and the direction of the propulsive thrust as a function of some important parameters related to the spacecraft attitude. Therefore, a reappraisal of the problem is motivated by the need to revise past results, taking into account new information available on the propulsion system. Within this context, this paper focuses on circular displaced orbits that are characterized in terms of orbital period, heliocentric distance and elevation angle. The attitude configuration and the value of the spacecraft characteristic acceleration required for orbital maintenance are calculated. An in-depth analysis of the linear stability of displaced orbits is given. It is shown that displaced orbits are unstable when the elevation angle exceeds about 20 .

Electric sail displaced orbit control with solar wind uncertainties

“…6 shows the approximate normalized PDF of r = r(θ) with θ ∈ [0, 180] deg, obtained both with the refined PDF and the gamma PDF of Eq. (7). The darker lines denote more likely trajectories.…”

“…The first mission case involves the maintenance of a heliostationary condition [7,25,43], that is, a mission that enables the continuous observation of the Sun's polar regions. Such a condition corresponds to when the Sun's gravitational pull equals the E-sail propulsive acceleration; see Fig.…”

“…Confining the study to circular DNKOs, these orbits are univocally defined by three parameters, that is, {ρ, ψ, ω K } where ρ is the distance between the spacecraft and the projection of O on the orbital plane, ψ is the elevation angle from the ecliptic plane to the position vector r, and ω K µ /r 3 is the reference angular velocity. The equations required for orbital maintenance are [7]…”

“…When an E-sail is immersed into the solar wind plasma, it generates a propulsive acceleration by exchanging momentum with the incoming ions. Possible mission scenarios that exploit an E-sail-induced thrust include deep space transfers to planets [3] or asteroids [4,5,6], generation of non-Keplerian orbits [7,8], maintenance of artificial Lagrangian points [9,10], and even more interesting options, such as manned Mars operations [11], outer Solar System exploration [12,13,14] and interstellar missions [15]. A derivation of the E-sail working principle, the plasma brake concept [16,17], could be used to deorbit a spacecraft from a low Earth orbit.…”

E-sail attitude control with tether voltage modulation

“…However, in a Sun-facing configuration the E-sail generates a purely radial thrust, while in most cases a trasverse thrust component is necessary for orbital maneuvers, since it allows the orbit angular momentum to be varied [13]. Typical advanced missions include the transfer towards linear trajectories [14], the maintenance of displaced non-Keplerian orbits [15,16], interplanetary rendezvous [17,18,19,20,21], or an escape from the Solar System [22,23,24]. A transverse thrust component may be obtained by inclining the sail nominal plane with respect to the local radial direction.…”