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DN-011 L: In situ lunar surface plasma environment characterization

Long-term measurements of the plasma at the South Pole surface (electron and ion density and energy up to 30 keV, secondary electrons and photoemission, and the electric potential of spacecraft and ground) in sunlight, shadow, PSRs and the terminator, through solar wind, Earth's magnetotail and space weather. The data validates the environment definitions used to assess electrostatic discharge, which "can interfere with communications, damage avionics, and introduce shock hazards to astronauts". It is named in the Moon Base Users Guide (near-term), under the long-duration challenge (Data gaps spreadsheet, DN-011 L; Users Guide, p. 12).

Quotations below are from row DN-011 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. 275).

Description

"Measure the plasma environment at the lunar south pole, including observations in the terminator region, permanently shadowed regions (PSRs), and in sunlit and shaded areas influenced by topography and spacecraft-induced wakes. Long-term measurements are needed to capture variations when the Moon is exposed to the solar wind, within Earth's magnetotail, and during dynamic space weather conditions. These observations should also include measurements of electric potential on both the spacecraft and the lunar surface."

Need driver and data type

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

Target measurement parameters

"Measure plasma electron and ion density and energy (0-30keV), secondary populations (secondary electron emission and photoemission), and spacecraft and lunar surface electric potential. Provide data in a format that allows comparison with other orbit-based plasma measurements and future measurements."

Current state of data

"Current estimates of the lunar plasma environment are from orbital satellite data, modeling, and limited in-situ surface measurements with temporal and spatial limitations."

Impact if data is unavailable

"Data used to validate the environment definitions in the M2M Design Specification for Natural Environments (DSNE). Plasma environment definitions are used to assess the risk of electrostatic discharge resulting from interactions between the plasma environment and surfaces. These data also support modeling of the dust environment and triboelectric charging analyses."

Benefits if data is available

"Validated lunar surface plasma environments ensure accurate inputs to spacecraft charging assessments, which are critical for identifying and mitigating electrostatic discharge risk. Electrostatic discharges can interfere with communications, damage avionics, and introduce shock hazards to astronauts, making reliable environment definitions critical for mission safety and success."

Traceability

  • Objectives: HS-03 LM, 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-011 L for one challenge (Users Guide, p. 12):

  • "Operating on the Lunar Surface for Long Durations" (headline challenge). 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.

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.

Sources

Data gaps spreadsheet, DN-011 L · Users Guide, pp. 11–12 · ADD Rev C, p. 275