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DN-018 L: In situ measurement of landing site alteration imaging at small scale on the lunar surface

How a rocket plume reshapes the landing site: topography before, during and after landing at cm-to-m scale, plus the regolith properties and chemical contamination of the disturbed area. LOLA mosaics go down to 5 m/pixel, and finer shape-from-shading DEMs depend on available NAC images. The stakes include leveling the vehicle and abort planning, with possible "loss of crew, loss of vehicle and loss of mission". It is named in the Moon Base Users Guide (near-term), under two challenges, landing and "Small cargo return" (Data gaps spreadsheet, DN-018 L; Users Guide, p. 12).

Quotations below are from row DN-018 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, "ins resolution" included (ADD Rev C, p. 282, PDF checked).

Description

"Characterize the landing site alteration caused by rocket exhaust plumes interacting with the lunar surface at different sites and under different plume conditions (i.e. lander types). During final descent and landing, rocket exhaust may erode material which changes surface topography or alters surface properties. This has the potential to create a hazardous landing environment or affect scientific outcomes."

Need driver and data type

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

Target measurement parameters

"Measurement of landing site topography before, during, and after vehicle plume-surface interactions at the cm-m scale. Measurement of regolith geotechnical properties in the affected area. Measurement of chemical contamination of the affected area."

Current state of data

"Modeling reports for preliminary site comparisons have been generated using regolith data gathered during Apollo coupled with engine performance data. Plume surface interaction is a complex phenomenon, and current estimates are insufficient to accurately predict the behavior of regolith and its effects on vehicle performance. Currently available topographic data comes predominantly from LRO's LOLA instrument. Localized mosaic DEMs are available at as low as 5 m/pixel ins resolution. Higher resolution DEMs can be made using shape-from-shading (SfS, or photoclinometry) image processing, where several high-resolution NAC images taken at various times lighting conditions) are used to create higher resolution DEMs over smaller areas. The resolution of these DEMs is dependent on the resolution of the available NAC images. Alternative solutions include cameras on landing and return vehicles, which can monitor landing site alterations induced by PSI during descent/ascent. Orbital imagery may be able to achieve desired resolution with high performance instrumentation and appropriate orbital configuration on a new mission."

Impact if data is unavailable

"Increased uncertainty in risk to landing vehicle caused by surface alteration. Increased uncertainty to scientific operations near the landing site if regolith alteration or contamination is not well understood. Inability to level the spacecraft properly due to lack of understanding of the terrain could lead to loss of crew, loss of vehicle and loss of mission (or combinations thereof). Inability to properly account for terrain topography in ascent and descent scenarios can potentially complicate abort response, potentially leading to loss of crew, loss of mission and loss of vehicle."

Benefits if data is available

"Increased confidence in analyses of surface alteration during final descent and landing. Informs vehicle design and operational mitigations. Informs scientific community regarding experiment placement and operations. Enhancement of vehicle preparedness for ascent and landing, increased ability of lunar rovers to traverse varied lunar terrain, determination of abort scenarios during ascent and landing. Understanding of the terrain also contributes to better response to terrain conditions through modifications to leveling hardware for lunar landers."

Traceability

  • Objectives: SE-07 LM, LI-05 L, 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-018 L for two challenges (Users Guide, p. 12):

  • "Landing Safely and Accurately on the Lunar Surface" (headline challenge). Its knowledge challenge has two sentences: "Observe the lunar surface to identify surface blocks, such as rocks and craters; map surface topology; and characterize variance in gravitational fields to enable precise and safe landings." and "Characterize and predict the properties of a plume-surface interaction (PSI) event, including ejecta trajectory, particle size distribution, and resulting surface site alterations to evaluate impact risk to mission and nearby assets." The guide lists DN-001 L, DN-014 L, DN-002 L, DN-017 L and DN-018 L under both sentences together and does not say which sentence each serves. The challenge's technology half cites tech gap #1101.
  • "Small cargo return": "Returning cargo from the lunar surface (e.g., scientific samples) requires a detailed understanding of how launch from the surface affects lunar regolith and nearby assets." Also cited: DN-017 L. No tech gap.

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 mission on the same subject (the wiki's link; no source pairs them): SCALPSS on Blue Moon MK1 "will capture high-resolution imagery before, during, and after landing" (Moon Base Phases, "Blue Origin's Blue Moon Mark 1"). NASA's technology page says SCALPSS produces "a 3D view of the surface" and measures "surface erosion and dust distribution caused by landing plumes" (Lunar Surface Technology, "Stereo Cameras for Lunar-Plume Surface Studies (SCALPSS)"). See the data gaps index.

A Moon Base payload with no phase, same subject (the wiki's link): DISCO, selected through PRISM in September 2026, will study "how rocket exhaust disturbs the ground" (PRISM release, "DISCO").

Cargo return in the Ignition material (the wiki's link, by the name of the guide's challenge). The Moon Base Program's Ignition deck has "Demo small cargo return" in Phase 2, and "Sustained small cargo return" and "Demo med/large cargo return" ("Goal: 500 kg") in Phase 3 (slide 62); its "Cargo Return" key mission has an "Initial demo in Phase 2" and uncrewed returns of "Science returns; Critical hardware; Inspiration" (slide 34) (Ignition deck 2, slides 34 and 62). It says nothing about the launch site's alteration. The full set of cargo-return lines is on DN-017 L.

Sources

Data gaps spreadsheet, DN-018 L · Users Guide, pp. 11–12 · Moon Base Phases, "Blue Origin's Blue Moon Mark 1" · Lunar Surface Technology, "SCALPSS" · ADD Rev C, p. 282 · PRISM release · Ignition deck 2, slides 34, 62