Exploration of Martian Lava Tubes

Christoph Brendel and Janko Trisic

1 Introduction

Study about the Lava Tubes on Mars

Can they provide shelter for humans in the future?

2 Source: Wikipedia Objectives

Define the main criteria for the lava tubes:

● Over 100 m wide ● Close to ancient ocean

● Possibility to contain water: find out if they contain H2O ice, separate those who have it from the rest

Find the tubes that meet the requirements

Find out if they can provide shelter for humans

3 The Lava Tubes

Skylights and rilles

Way bigger than the ones on Earth Source: Wikipedia

Source: http://blogs.esa.int/caves/2015/05/06/caves-the-hidden-side-of-planets/ Red line represents 50m 4 Source: Google Images. Ancient ocean

“Oceanus Borealis”

Still a hypothesis, but with many features that back it up:

● Shorelines ● Flow lines ● Clay sediments ● Cross bedding

4.1-3.8 Billion years ago

5 Location

Many volcanoes on Mars

Areas with the highest rates of lava tubes: Tharsis and Elysium

Tharsis has plenty volcanoes but is far away from theoretical shore

Elysium is in the middle of hypothetical ocean

Source: Google Earth 6 Elysium Mons

Good location

Rootless cones

Lava tubes

7 Lava tubes locations

Olympus Mons

Elysium Mons Pavonis Mons

Arsia Mons

8 Rootless cones

9 http://www.dronestagr.am/pseudocraters-in-myvatn-lake-iceland/ B. C. Bruno / Spatial Analysis of Rootless Cone Groups on Iceland and Mars 10 Criteria

Skylights: Rootless cones: Lava tubes:

GPR Optical imaging Optical imaging

● Hyperbolas in cross section and ● Diameter of 80-200 m ● Diameter between 0.5 km and 1.5 continuous lines on longitudinal ● Hole in the surface km section ● Shadows within the circle ● No central mountain in the crater

Gravimetry

● Gravimetric anomalies

11 Optical imaging

Minimum resolution Available resolution

Skylights 30 m/pixel 0.3 m/pixel

Collapsed 30 m/pixel 0.3 m/pixel Tubes

Rootless Cones 15 m/pixel 0.3 m/pixel

12 Optical imaging

Lava tube southeast of Elysium Mons, approx 130m in diameter

150 m

13 Elysium Mons

Nasa/JPL/University of Arizona / https://www.uahirise.org/ESP_035098_2065 14 500 m

d = 0.7 km

d = 1 km

15 A: hyperbola marking a cavity

B: Ice layer C: water layer

If we analyzed a scan that was cutting the tube, we would see the hyperbola from figure A.

If we were to scan along the tube, we would see a constant, horizontal line

16 Gravity anomaly

C. Rowell / Geophysical analysis of structures and flow geometry of the Blue Dragon lava flow

17 Methods From Earth:

● Analysis of previous imaging and GPR data

From orbiter:

- SHARAD - 20 MHz - MARSIS - between 1,8 and 5 MHz - HiRISE images - resolution of 0.3 m/pixel - Spectrometer (CRISM)

From Orbit:

● Radar sounding (GPR) ● Gravity anomaly

On site:

● Lander: GPR and gravimetric tools ● Helicopter 3D modeling 18 Methods

Methods that could be provided Methods that need more Currently available methods in the next few years research and better technology

High resolution imaging from Mars orbit 3D modeling with a helicopter Robotic exploration the caves Shallow and ground penetrating radar on orbiter Human exploration of caves

Spectrometer on orbiter

Tracing of gases

19 25 MHz 5 MHz 0.5 MHz

Material v in m/ns λ depending on frequency vacuum 0.3 12 60 600 fresh water 0.034 1.36 6.8 68 basalt 0.11 4.4 22 220 clay 0.15 6 30 300 granite 0.13 5.2 26 260 ice 0.16 6.4 32 320 limestone 0.13 5.2 26 260 permafrost 0.15 6 30 300 sand 0.15 6 30 300 volcanic ash 0.09 3.6 18 180 20 3D modeling of lava tubes

● JPL Mars Helicopter Scout will be on board of the Mars 2020 mission

● If the helicopter is a success, 3D modeling of the entrances will be available

21 Exploration with robots

● Getting the robot into the cave is very challenging

● Data transfer from within the cave is limited

○ Ceiling very thick

22 Exploration with robots

R. Whittaker / Technologies for Exploring Skylights, Lava Tubes and Caves - NASA 23 Conclusion

Detection of lava tubes is already possible

Modeling of the entrances is possible in the near future

Entering the caves is still a huge obstacle

High importance for humanity if we intend to colonize Mars

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