Space can be an unforgiving environment that challenges spacecraft to operate reliably for extended missions. Engineers develop power systems with redundancy in mind to reduce system failure risk that might jeopardize a mission.
The main EPS inverters utilize 30 V DC from the maneuver booster regulator and convert it to the 2.4 kHz square wave AC used by spacecraft subsystems, as well as managing temperatures of radioisotope thermoelectric generators (RTGs).
Redundancy
Spacecraft power systems must operate reliably in an unpredictable environment such as space. Therefore, redundancy plays an essential role in power systems design: duplicating essential components and systems so that in case one breaks down seamlessly another can take its place seamlessly.
Redundancy provides increased reliability and fault tolerance, increased astronaut safety, improved adaptability to unexpected situations and minimized downtime. Redundancy is especially crucial as aerospace equipment is so expensive and complex it cannot easily be repaired or replaced.
To address these challenges, the EPS modular design combines PV modules, charge controllers, battery packs and power distribution components into one module, reducing NRE, lead time and AIT costs while streamlining AIT processes. Furthermore, redundant parallel switches with fail safe configuration are utilized to reduce parasitic loads or single event latch-up in semiconductor devices from leading to failures of this nature.
Efficiency
Spacecraft power systems must perform with maximum efficiency for maximum impact and operational lifespan; doing so reduces weight and volume while freeing up more resources to be dedicated toward energy management functions.
Spacecraft electrical power systems (EPSs) generate, store, regulate and distribute energy using solar panels, nuclear fuel cells or batteries as a source.
Interface technology between energy storage systems and spacecraft subsystem components must be capable of regulating high output voltage, managing power distribution and offering fault protection. Bradford Space/Deep Space Industries’ Nova PCDU features a 28V non-isolated synchronous buck that offers various configurations to meet mission requirements – such as solar array peak power tracking/conversion, battery charge regulation, low voltage buses with fault protected distribution switches as well as multiple topologies and applications on spacecraft platforms.
Solar Power
Sunlight provides an endless source of energy. Satellites that orbit Earth typically use solar panels to convert this abundant resource into electricity for use by their onboard electronics. Solar cells account for much of a satellite’s overall power requirements.
Solar radiation poses unique difficulties when applied in space, with wires connecting Earth-bound satellites not feasible due to distance variations from the Sun as well as interference from space junk and radiation.
Don Bren and his family have provided funding for the Solar System Power Distributor (SSPD). It aims to develop and test “solar-power-satellites,” or powersats, that utilize advanced photovoltaic cells and microwave transmitters in order to transmit captured solar radiation back down towards Earth’s surface.
John Mankins, a former NASA engineer, introduced an innovative solution known as SPS Alpha in 2012. This design keeps solar panels and transmitters stationary while employing rotating mirrors that channel light directly towards solar cells.
Batteries
Spacecraft are dependent on electricity for all their functions, from astronauts’ spacesuits and cameras and satellites that collect information back to Earth to cameras that gather intelligence for us on Earth. Spacecraft need reliable power supplies that are designed to work in unusually harsh conditions like radiation or extreme temperature extremes; battery packs must also avoid overheating and overcharging as this poses serious safety concerns that could result in explosions or fire.
Lithium-ion rechargeable batteries are the latest power option available to spaceflight, being significantly more powerful than their NiMH predecessors. Each commercially available lithium-ion cell packs about three times more power than its NiMH equivalent; thus enabling scientists to explore celestial bodies far beyond our Sun, making exploration possible that would otherwise have been impossible.