---
type: source
title: "Potential Subsurface Lava Tube Skylight on the Western Flank of Elysium Mons, Mars"
author: "Sauro et al. (The Astronomical Journal / IOPscience)"
url: https://iopscience.iop.org/article/10.3847/1538-3881/adbe32
date: 2025-01-01
domain: space-development
secondary_domains: []
format: article
status: processed
processed_by: astra
processed_date: 2026-05-02
priority: medium
tags: [mars, lava-tubes, skylight, Elysium-Mons, cave, settlement, radiation-shielding, ISRU]
intake_tier: research-task
extraction_model: "anthropic/claude-sonnet-4.5"
---

## Content

Published in The Astronomical Journal (IOPscience), approximately early 2025. Full investigation of a potential subsurface lava tube skylight on the western flank of Elysium Mons, Mars.

**Discovery:** Elliptical structure with constant shadowed regions and partial roof collapse identified on Elysium Mons western flank. High-resolution imagery from CTX and HiRISE (Mars Reconnaissance Orbiter) across varying solar angles rules out illumination artifacts.

**Investigation methodology:**
- High-resolution imagery (CTX, HiRISE) at varying solar angles
- Thermal observations (THEMIS) — structure retains heat, shows warmer appearance vs. surroundings, indicating connectivity with subsurface cave environment
- Topographic analysis (MOLA/HRSC)
- Geological and mineralogical analyses (CRISM)

**Key thermal finding:** Warmer thermal signature = subsurface connectivity. The pit is thermally buffered compared to surrounding surface — consistent with a cave environment that moderates temperature extremes. This has dual significance: (1) confirms subsurface connection, (2) suggests cave interior temperatures may be less extreme than surface (~-60°C range vs. surface extremes of -125°C to +20°C).

**Research from Research Square (preprint):** "Strategic Exploration of Elysium Mons Cave Zone on Mars: Implications for AI-Driven Robotic Dogs" — suggests deployment of quadruped robots (like Boston Dynamics Spot-class) for reconnaissance before human entry. Consistent with Astra's robotics-space intersection theme.

**Geographic context:**
- Elysium Mons is in the Elysium volcanic province (~24°N, 147°E)
- Western flank of Elysium faces TOWARD Amazonis Planitia (the ice-rich low plains documented by Luzzi 2025)
- This proximity is the critical co-location data point: lava tube on the slope of Elysium Mons, facing the direction of Amazonis Planitia's shallow ice

## Agent Notes
**Why this matters:** This is the most recent (2025) identified lava tube candidate on Mars, and it happens to be geographically positioned between Amazonis Planitia (shallow near-surface ice, Luzzi 2025) and the main Elysium volcanic edifice. The western-flank position is the key detail — it faces the ice-rich plains.
**What surprised me:** The thermal data confirming subsurface connectivity is stronger evidence than expected. Previous "skylight" candidates were identified from imagery alone; this one has thermal + imaging confirmation.
**What I expected but didn't find:** Size characterization. The diameter of the entrance and the potential interior volume are not specified in search results. Arsia Mons caves are 100-250m diameter; Elysium Mons cave dimensions are unknown from available abstracts.
**KB connections:** The Mars radiation engineering prerequisite established in May 1 session (regolith/underground habitat), [[power is the binding constraint on all space operations because every capability from ISRU to manufacturing to life support is power-limited]], the near-surface ice finding (Luzzi 2025 archive)
**Extraction hints:** Primary claim: "A thermally-confirmed subsurface lava tube skylight on the western flank of Elysium Mons (2025) positions a candidate radiation-shielded habitat within potential proximity of the near-surface ice deposits of Amazonis Planitia, representing the strongest current co-location evidence for simultaneous radiation protection and water ISRU." Secondary: thermal buffering of cave interior as a habitability advantage beyond radiation shielding.
**Context:** IOPscience / The Astronomical Journal is peer-reviewed. The companion Research Square preprint about robotic reconnaissance is a preprint — lower credibility for specific claims, but confirms that the cave exploration robotics community is already planning for this site.

## Curator Notes (structured handoff for extractor)
PRIMARY CONNECTION: The May 1 session claim candidate: "Mars surface GCR requires covered/underground habitat construction as engineering prerequisite" — this site is where the engineering solution meets a specific geography
WHY ARCHIVED: Most recent (2025) Mars lava tube candidate, thermally confirmed, positioned near Amazonis Planitia ice. Directly tests the co-location hypothesis that was today's research question.
EXTRACTION HINT: Combine with Luzzi 2025 (ice) and the npj 2026 Tharsis paper (historical water) for a tripartite Mars settlement infrastructure analysis. The three papers together make a claim no single paper makes.
