Global database of direct solar radiation at the Moon’s surface for lunar engineering purposes

Abstract

The purpose of this paper was to provide preliminary data concerning global availability of solar energy at the surface of the Moon. Lack of gaseous atmosphere and accompanying phenomena such as precipitations or cloud cover makes the Moon's surface an extraordinarily advantageous place for solar energy harvesting. On the other hand, excessive exposure to undamped sunlight may cause problems with buildings' interior overheating or increase decay rate of photovoltaic cells. Thus, basic information concerning solar irradiance and diurnal insolation at specified selenographic latitudes are indispensable for location selection for future lunar facilities and their design process. In order to approximate Sun's position at lunar sky, simple analytical astrometric model of lunar rotation was developed. Basing on that model, direct diurnal irradiances and insolations were calculated for various flat surface orientations, and selenographic latitudes. Computed data were presented in charts and tables.This lunar insolation database may serve as guideline for location of future lunar settlements and research stations, and to estimate their diurnal energy demands.

Parametric Study of a Lunar Base Power Systems

“…During the three decades that passed since, PV technologies have made considerable advances and today's space solar cells offer stateof-practice multijunction cells with efficiencies up to 32% [38]. Due to the lack of atmosphere, the Moon is an extraordinarily advantageous place to harness solar energy [39]. The most notable advantage of solar cells as a power source is their very high specific power (power-to-mass ratio, PMR).…”

“…The greatest limitation of any Solar-based power system at the lunar surface reveals itself due to exceptionally long lunar nights. Owing to the relatively slow rotation of the moon, an average lunar cycle (LC) also known as the synodic month, lasts 29.531 earth days [39]. It implies that the solar-powered lunar base must be equipped with an energy storage solution of considerable capacity, which would guarantee the functioning of a base for more than the two-week-long lunar night.…”

“…In 1722 Jacques Cassini demonstrated, that the axial tilt of the Moon equals 1.54° and is constant in time [39,59]. With its axis of rotation almost perpendicular to the ecliptic plane, the Moon has practically no seasons but remains in a state of permanent equinox.…”

“…where: TSI-total solar irradiance at the Moon's surface, equal to 1360 W/m 2 according to [39]; ηSC-nominal energy efficiency of the solar cells. ηSC = 32% was assumed for the quadruple multijunction space solar cells, according to the manufacturer's specifications [38]; ηenv-mean expected environmental efficiency of the solar cells at the Moon's surface, due to the exposure to the local temperatures and cosmic radiation environment; for the selected cells ηenv = 80% was assumed according to [40]; fSA-solar array fill factor (ratio of the solar cell area to the array area), fSA = 89% [27]; CST-the Sun tracking coefficient; its meaning is explained below and the values presented in Table 6.…”

“…One of the parameters we intended to study in this paper was the orientation of the PV panels during the lunar day. Common practice for lunar PV systems is to use a fixed mount for the solar panels and to orient the array toward the equator with its tilt angle equal to the site latitude [27,28,37,39]. This orientation is considered optimal as it guarantees the highest insolation for fixed PV panels.…”