NanoSWARM: NanoSatellites for Space Weathering, Surface Water, Solar Wind, and Remanent Magnetism

Abstract

The NanoSWARM mission concept is a detailed investigation of particles and magnetic fields to help characterize the surfaces of airless planetary bodies, their volatile element distributions, and their geophysical histories. NanoSWARM investigates unique regions in the solar system where these processes come together: lunar swirls.NanoSWARM would be the first demonstration of a planetary-class carrier vehicle equipped with dozens of nanosatellites, each capable of performing measurements either too risky or difficult for the carrier. This architecture greatly facilitates contributed nanosatellites and complete sub-missions from other nations, students, or participating scientists. NanoSWARM was proposed to theDiscovery program in 2019. It was one of 6 missions that received the highest possible ranking of Category 1, but it did not move forward to Phase A. The commercial space flight community is well on its way toward mass production of small spacecraft. An openness within the planetary community toward building dozens of instruments or spacecraft could open up entirely new regimes of measurement in space.1. Science overview: NanoSWARM (NanoSatellites for Space Weathering, Surface Water, Solar Wind, And Remanent Magnetism) uses a new type of space mission architecture to address four complementary science goals, becoming, in effect, four missions in one. NanoSWARM launches 19 NanoSatellites (plus spares) to fly just above the surface at five target sites spread across the Moon's near and far sides. This architecture permits a science investigation of substantial breadth and depth, beyond what could be accomplished with a single orbiter, rover, or lander.NanoSWARM's first goal is to elucidate the mechanisms of space weathering -the alteration of an airless body's optical properties due to solar wind and micrometeoroid bombardment. This ubiquitous process affects spectral data from 0.1-10 microns and, thereby, our ability to determine the compositions of bodies ranging from Mercury to asteroids. Despite decades of study, we do not have a complete model for how space weathering operates. In particular, the relative contributions from micrometeoroids and solar wind flux and the influence of local soil mineralogy on the optical effects are not completely understood. To address this problem, NanoSWARM investigates unique locations on the Moon where solar wind flux is modified while the micrometeoroid flux and mineralogy remain constant: lunar swirls (Fig. 1). The M 3 instrument on Chandrayaan-1 as well as Diviner and LAMP on Lunar Reconnaissance Orbiter (LRO) quantified the spectral variations across these features. By performing the first spatially resolved near-surface solar wind flux measurements across multiple swirls with different soil iron contents, NanoSWARM quantitatively resolves how the solar wind affects the optical properties of the Moon and similar silicate bodies.NanoSWARM's second goal is to constrain how near-surface water forms and is distributed on airless bodies like the Moon, Mercury, and asteroid...