SSPARE: Space Solar Power Autonomously Reconfigurable Elements

TL;DR

This paper tackles the reliability bottleneck of GEO satellites by targeting the power subsystem, which data indicate is the dominant long-term failure driver. It introduces SSPARE, a self-servicing, modular power architecture that unifies solar generation and storage in detachable Space Solar Power Modules (SSPMs) and employs a forklift-inspired unloading mechanism for autonomous assembly and replacement. The approach promises up to sixfold power per launch over traditional GEO configurations and offers rapid on-orbit repair without dedicated servicing missions, with a cost-benefit profile favoring SSPARE over existing MEV-1 style interventions. If realized, SSPARE could enable scalable space solar power infrastructure and significantly improve mission assurance for space assets, advancing toward Earth independence through on-orbit power farms.

Abstract

GEO communication satellites generate significant revenue but can only function reliably for approximately 10 years on orbit. One of the main drivers that limits the reliability of a GEO satellite is the electric power system, and in particular, anomalies related to batteries and degradation of the solar arrays. Given the high cost and relatively short lifespan of GEO satellites, there has been increased research activity towards developing on-orbit servicing systems. However, most of the existing servicing systems are expensive, highly customized, and focus on refueling tasks. On-orbit refueling can be very useful, however, it does not improve satellite reliability which is crucial for long-term missions. Therefore, we propose SSPARE (Space Solar Power Autonomously Reconfigurable Elements), a cost-effective, self-servicing power system. Aside from improving satellite reliability, SSPARE enables to generate up to 6 times more power per launch compared to a traditional GEO communication satellite. This study explores why GEO satellites fail and elaborates on the SSPARE concept. A comparison of SSPARE against a traditional on-orbit servicing mission highlights the benefits of the proposed concept. With humanity striving to become more and more Earth-independent, this work aims to build a foundation for future systems such as large solar power farms on-orbit.

Figures (7)

• Figure 1: Illustration of the SSPARE concept
• Figure 2: Reliability of small ($\leq$ 500kg), medium (500kg$-$2,500kg) and large ($\geq$ 2,500kg) satellites over their years of operation. Clear drop in reliability of large satellites after year 7. Adapted after Dubos et al.
• Figure 3: Satellite failure modes after 10 years of operation. Satellites from 1990-2019 weighing between 40k g-500k g were considered. The main failure mode is the electric power system at 44%. Adapted after Perumal et al.
• Figure 4: Intelsat 901 with SSPARE modules stored inside of a standard Falcon fairing. The grey columns on the sides of the SSPARE modules represent the rods. The rods are part of the unloading system and limit the stacking height. The rods reach a tapered fairing diameter of 2.6m.
• Figure 5: Proposed unloading system of SSPARE. A) The space solar power modules are stacked on top of the satellite. The right connector docks to the top module and lifts it up. B) The connector moves up and down the rod. The spiral guide at the top of the rod enables the connector to turn 180 degrees. C) The connector places the module on the base module from which it can unfold and move into place.