Plasmonic Force Propulsion for Small Spacecraft

Abstract

Plasmonic force propulsion uses solar light focused on deep-subwavelength nanostructures to excite strong optical forces that accelerate and expel nanoparticle propellant. The concept was assessed within the context of precision pointing and position control for nano/pico-satellites. Plasmonic force fields were numerically simulated, propulsion performance predicted and then used to evaluate spacecraft position control resolution and pointing precision. Results for a conceptual design of a plasmonic thruster that has 35 layers, 86 array columns, multi-stage length of 5 mm, a 5-cm-diameter light focusing lens, and uses 100 nm polystyrene nanoparticles expelled at a rate of 1x10 6 per sec would have a thrust of 250 nN, specific impulse of 10 sec, and minimum impulse bit of 50 pN-s. The thruster mass and volume are estimated at 100 g and 50 cm 3 , respectively. Results predict plasmonic force propulsion can enhance the state-of-the-art in small spacecraft position and attitude control by 1-2 orders of magnitude. This has the potential to enable advanced missions that require ultra-fine pointing precision to less than 0.1 milliarcsecond. Nomenclature A = area [m 2 ] B = magnetic field [T] E = electric field [V/m] F = force [N] I = intensity [W/m 2 ] I sp = specific impulse [sec] J = current density [A/m 2 ] L = acceleration length [m] M e = mass expended [kg] N = number of array elements P = power [W] T = thrust [N] T ij = Maxwell stress tensor V = volume [m 3 ] or velocity [m/s] a = acceleration [m/s 2 ] f = force per unit volume [N/m 3 ] or expulsion rate [sec -1 ] g o = gravitational constant [9.81 m/s 2 ] m = mass [kg] t = time [sec] v = velocity [m/s] 2 x = position [m] ρ = charge density [C/m 3 ] ε o = permittivity of free space µ o = permeability of free space δ ij = Kronecker delta function

Study on the Optical Field Distribution of Asymmetric Nanostructures Based on Surface Plasmon

“…The size of the asymmetric nano-structure can be adjusted to enhance the plasma local field distribution. The transverse optical tweezers force in the gap can always keep the particles in the middle space of two trapezoids in a suspended state [17], [18]. As shown in Fig.…”