Ultra-Thin, Flexible InGaP Solar Arrays Embedded In Solar Sails for Power Generation

Solar sail missions can only use embedded photovoltaic (PV) arrays that are low-mass, high-performance, radiation-hard, and stable in near sun environments. Amorphous Si (<10% AM0 eff.) and CIGSe (< 11%) have been tested for these reasons, but their already low efficiency drops at high temperature. MicroLink Devices proposes a single junction (SJ) epitaxial lift-off (ELO) InGaP PV device that can be embedded in solar sails. ELO removes the PV device structure from the growth substrate, providing ~50x mass reduction, ~30% cost reduction, and results in very flexible PV. It allows for a back surface that reflects ~80% of solar photons (> 650nm), provides thrust, enables low temperature operation in near Sun environments (~50oC cooler vs. conventional space PV), and simplifies power management and distribution. High efficiency is expected under operating conditions (>15% AM0 eff., >900 W/kg) with excellent radiation tolerance (<4% drop at 1 x1015 e/cm2, 1 MeV electrons). These features make the proposed cell an ideal candidate for powering distributed solar sails.