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DN-019 L: In situ measurement of lunar regolith (dust) particle flux and charge

The electric charge of individual dust particles as they hit spacecraft surfaces in the South Pole region, and the dust flux over time, fast enough to catch transient events such as plume-surface interaction. Today's estimates come from "modeling, ground testing, and limited in-situ surface measurements". Without data, dust accumulation, spacecraft charging and electrostatic discharge are hard to predict. It is named in the Moon Base Users Guide (near-term), under six challenges, tied with DN-009 L for the most of any data gap; it is the only data gap cited for "Thermal generators" and one of two (with DN-005 L) for "Solar power" (Data gaps spreadsheet, DN-019 L; Users Guide, pp. 12–13).

Quotations below are from row DN-019 L of the data gaps spreadsheet unless marked otherwise. ADD Rev C's Appendix E prints the same record as a table, and it matches the row field for field (ADD Rev C, p. 283).

Description

"Measure the electric charge and flux of regolith (dust) particles impacting spacecraft surfaces in the lunar south pole region. Measurements over long durations and during dynamic events, such as PSI, are needed to characterize the variability of lunar dust accumulation and electrostatic charging on vehicles and assets, including EVA suits."

Need driver and data type

  • Need driver: Lunar Surface Induced Environment Characterization
  • Data type: In Situ Measurement

Target measurement parameters

"Measure electric charge of individual regolith particles upon impact and the flux of dust particles over time with a temporal resolution sufficient to capture transient events such as PSI."

Current state of data

"Current estimates are from modeling, ground testing, and limited in-situ surface measurements with temporal and spatial limitations."

Impact if data is unavailable

"The absence of in-situ measurements introduces uncertainty in predicting dust accumulation and its effects on spacecraft systems, including its contribution to spacecraft charging and electrostatic discharge. This uncertainty limits the effectiveness of dust mitigation strategies and increases the risk to crewed and robotic assets operating in dusty environments."

Benefits if data is available

"Measurements enable the development and validation of models for dust charging, transport, and surface accumulation. These models will inform the design of spacecraft materials and systems that are more resilient to dust-related effects. Additionally, the data will support the refinement of operational procedures and risk assessments for surface missions, enhancing mission safety and longevity."

Traceability

  • Objectives: AS-01 LM, TH-03 L (codes as printed; the sheet gives no titles)
  • Segment: Human Lunar Return (HLR): "The M2M segment during which the data is needed, but not necessarily when it is collected" (Data gaps spreadsheet, Key sheet). A segment is not a Moon Base phase.

Priority

None. The spreadsheet has no priority field, and the Users Guide calls the data-gap list "not comprehensive or prioritized" (Users Guide, p. 11).

Moon Base relevance

The Users Guide names DN-019 L for six challenges (Users Guide, pp. 12–13):

  • "Operating on the Lunar Surface for Long Durations" (headline challenge, p. 12). Its knowledge challenge has two sentences: "Characterize the lunar surface environment to predict performance impacts and risks associated with long duration surface operations." and "Investigate dust mechanics, regolith geotechnical properties, and radiation/charged particle fluctuations, seasonal patterns, and scattering." The guide lists DN-008 L to DN-013 L, DN-015 L, DN-016 L and DN-019 L under both sentences together and does not say which sentence each serves. The challenge's technology half cites tech gaps #0101, #0201, #0301, #0801 and #0804.
  • "Manipulating regolith" (p. 13): "Manipulating lunar regolith at scale for excavation, compaction, and site preparation requires in depth understanding of regolith properties and large scale excavation and construction." Also cited: data gaps DN-008 L, DN-009 L and DN-010 L; tech gaps #0505 and #0605.
  • "Solar power" (p. 13): "Deploying systems to generate, store, and distribute solar power requires precise knowledge of lighting conditions and array performance, as well as systems robust to the lunar environment." Also cited: data gap DN-005 L; tech gaps #0504, #0901 and #0903.
  • "Thermal generators" (p. 13): "Using radioisotope thermal generators (RTGs) to provide survive the night capabilities requires detailed knowledge of the lunar environmental and systems that can operate there." DN-019 L is the only data gap cited. Also cited: tech gaps #0301 and #0901.
  • "Electrical connections" (p. 13): "Connecting systems and sharing power on the lunar surface requires dust tolerant connections and the ability to deploy cables." Also cited: data gaps DN-008 L and DN-009 L; tech gap #0903.
  • "Pressurized mating" (p. 13): "Mating pressurized systems on the lunar surface requires dust tolerant systems, which rely on detailed knowledge of lunar regolith and the surface environment." Also cited: data gaps DN-008 L, DN-009 L and DN-010 L; tech gap #0807.

The guide ties its challenges to "near-term Moon Base development efforts": missions in phase one "offer opportunities to collect data and mature technologies to enable essential phase two and phase three capabilities" (p. 11). See Technology and knowledge challenges.

Phase 1 missions on the same subject (the wiki's link; no source pairs them): LDES, on Griffin-1 and IM-3, "will measure how lunar dust accumulates on spacecraft and surface systems" (Moon Base Phases, "Voyager Technologies' Griffin‑1", "Intuitive Machines' IM‑3"). That covers accumulation; the page doesn't say LDES measures particle charge, which DN-019 L also asks for. IM-3 lands at Reiner Gamma, not the South Pole. See the data gaps index.

Sources

Data gaps spreadsheet, DN-019 L · Users Guide, pp. 11–13 · Moon Base Phases, "Voyager Technologies' Griffin‑1", "Intuitive Machines' IM‑3" · ADD Rev C, p. 283