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DN-005 M: In situ measurement of particle velocity during Martian plume surface interaction (PSI) phenomena

The Mars counterpart of DN-017 L: sizes, speeds and ejection angles of regolith thrown up by a lander's plume, plus the local atmospheric density during the event, since on Mars ejecta trajectories also depend on the atmosphere. The engineering cameras on the MSL and Mars 2020 sky cranes filmed exhaust plumes, but they "would not be able to characterize full descent profile of a human class lander". No source ties it to the Moon Base (Data gaps spreadsheet, DN-005 M).

Quotations below are from row DN-005 M of the data gaps spreadsheet. 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. 288).

Description

"Characterize Martian regolith ejected by rocket exhaust plumes interacting with the surface. During final descent and landing, material may be lofted toward the landing vehicle and/or ejected away. As material leaves the influence of the exhaust plume, it will travel on a trajectory dictated by those initial conditions and interactions with the Martian atmosphere."

Need driver and data type

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

Target measurement parameters

"Regolith particle sizes, speeds, and angles of ejection caused by rocket exhaust interacting with the Martian regolith. Local atmospheric density during plume surface interaction."

Current state of data

"Exhaust plume captured by engineering cameras aboard MSL and Mars2020 Sky Crane. Potentially able to estimate particle velocity from videos of descent but would not be able to characterize full descent profile of a human class lander."

Impact if data is unavailable

"Increased uncertainty in risk to landing vehicle and surrounding assets caused by debris strike or the "sandblasting", abrasive effects of ejected material. Increased uncertainty to scientific operations near the landing site, as the probability of surface alteration caused by ejected material may not be well constrained."

Benefits if data is available

"Increased confidence in ejecta hazard analyses that affect the landing vehicle and nearby assets. Tighter design constraints for protection from hazards/operating conditions. Better understanding of induced landing environment to inform Mars surface science goals."

Traceability

  • Objectives: SE-07 LM, TH-06 M, TH-07 M (codes as printed; the sheet gives no titles). SE-07 LM also appears on the lunar PSI gaps DN-017 L and DN-018 L.
  • Segment: Humans to Mars (H2M): "The M2M segment during which the data is needed, but not necessarily when it is collected" (Data gaps spreadsheet, Key sheet).

Priority

None. The spreadsheet has no priority field. The white paper calls the Rev C list "not a comprehensive or prioritized representation of NASA's data needs" (ACR25 data-gaps white paper, p. 4).

Moon Base relevance

Not established by the sources so far. The Users Guide's data-gap mapping covers lunar gaps only (Users Guide, pp. 12–13).

Sources

Data gaps spreadsheet, DN-005 M · ACR25 data-gaps white paper, p. 4 · Users Guide, pp. 12–13 · ADD Rev C, p. 288 · Mars EDL Challenges (2024), p. 4