# Presentation: 258095

## The Gale Crater Mound: A Candidate Landing Site for the 2009 Mars Science Laboratory

**The Gale Crater Mound: ****A Candidate Landing Site for the 2009 Mars Science Laboratory**

- Jim Bell1, Ken Edgett2, Scott Rowland3, Mike Malin2
- Representing the MSL Mastcam/MAHLI/MARDI Science Team
- 1Cornell U.; 2Malin Space Science Systems; 3U. Hawaii
- First MSL Landing Site Workshop
- May 31, 2006

## Outline

- Scientific Justification: Why MSL to Gale?
- Site information
- Proposed Ellipse and Traverse Options
- EDL and Trafficability
- Summary

- JFB: 5/31/06

## Gale Crater

- Located at 5°S, 137.5°E (222.5°W) in the northeast Aeolis quadrangle, near the highlands/lowlands boundary
- 140-172 km diameter, named after the Australian eclipse & transit astronomer Walter F. Gale (1865-1945)
- MOLA Heights (Parker)
- • Plains/Plateau: -1.1 to 0.0 km
- • Floor: -4.5 km; Mound: +0.3 km

- 5°S

- 135°E

- 140°E

- JFB: 5/31/06

## Science Case / MSL Relevance

- Key previous studies:
- Viking/Mariner imaging: Scott *et al.* (1978); Greeley & Guest (1987); Grin & Cabrol (1997); Kuzmin *et al.* (1998);Cabrol *et al.* (1999)
- and MGS MOC, MOLA: Malin & Edgett (2000, 2001); Edgett & Malin (2001)
- and MGS TES; ODY THEMIS: Pelkey & Jakosky (2002); Pelkey *et al.* (2004)
- Complementary talk here by N. Bridges

- JFB: 5/31/06

## Gale Crater

- Highest point exceeds rim by ~1 km

- Highest point exceeds
- rim by ~1 km

- 40-50 km wide central mound

- JFB: 5/31/06

## Slide 6

- JFB: 5/31/06

## Gale Crater Central Mound

- Indurated, layered, possibly rocky materials partially covered by dust based on physiography, albedo, and color information
- Compositional information ambiguous: significant dust & sand cover reduces spectral contrast in currently-available data
- Distinct layering of outcrops suggests a sedimentary origin, although an igneous origin cannot be ruled out
- Angular unconformities, filled and exhumed  channels, & other buried  and exhumed  erosional surfaces record significant changes in the depositional and erosional regime of this region regardless of the rock type
- Interpretation: Apparently, Gale and perhaps much of the surrounding region was completely buried and exhumed, at least once

- JFB: 5/31/06

## Slide 8

- JFB: 5/31/06

## Unconformity; buried erosional surface

- (MOC M03-01521)

- 500 m

- JFB: 5/31/06

## Evidence for channels cut into the layered rock, then subsequently buried and re-exposed (inverted)

- (MOC M03-01521)

- JFB: 5/31/06

## Perspective view of exhumed channel

- 200 m

- JFB: 5/31/06

## Gale crater has had a complex history of erosion and deposition (likely sedimentary, but possibly volcanic?)
Mound is a remnant of a once-larger deposit that may have filled the entire crater (and more)
The mound consists of hundreds of thin (< 10 m) beds in distinct units of similar thickness and material properties
Partially-exhumed craters (erosional unconformities) in some units indicate significant time between some depositional epochs
Evidence for channels cut into the layered rock, then subsequently buried and re-exposed (inverted)
Evidence for deposition of younger, massive units of light-toned materials at the top of the sequence

- Mound is a remnant of a once-larger deposit that may have filled the entire crater (and more)
- The mound consists of hundreds of thin (< 10 m) beds in distinct units of similar thickness and material properties
- Partially-exhumed craters (erosional unconformities) in some units indicate significant time between some depositional epochs
- Evidence for channels cut into the layered rock, then subsequently buried and re-exposed (inverted)
- Evidence for deposition of younger, massive units of light-toned materials at the top of the sequence

- Science Case / MSL Relevance

- JFB: 5/31/06

## One Gale history model...  (Edgett & Malin, 2000)

- JFB: 5/31/06

## One Gale history model...  (Edgett & Malin, 2000)

- JFB: 5/31/06

## One Gale history model...  (Edgett & Malin, 2000)

- JFB: 5/31/06

## One Gale history model...  (Edgett & Malin, 2000)

- JFB: 5/31/06

## One Gale history model...  (Edgett & Malin, 2000)

- JFB: 5/31/06

## One Gale history model...  (Edgett & Malin, 2000)

- JFB: 5/31/06

## One Gale history model...  (Edgett & Malin, 2000)

- JFB: 5/31/06

## Gale captures the essence of the larger, global picture:

-               Chinle
- Triassic  Moenkopi)

-                 Kaibab Ls
- Permian  Toroweap
-                 Coconino Ss
-                 Hermit Sh

-                  Muav Ls
- Cambrian Bright Angle Sh
-                  Tapeats Ss

-       • The mound is a layered, cratered, channeled volume.
-       • The story recorded there is rich and complex.
-       • The crater itself was filled, buried, then exhumed (at least once, maybe more).

- Edgett & Malin, 2001)

- JFB: 5/31/06

## Proposed 20 km Ellipse

- • MOC mosaic, >30 images, 2/06 (Ken Edgett)
- • Ellipse is on a fan of material transported through a valley that cuts/runs down Gale’s wall in the northwest quadrant of the crater

- N

- JFB: 5/31/06

## THEMIS-VIS mosaic of all Gale images as of Oct. 2005

- • Initial version, for THEMIS science team
- • In false color where there is VIS color coverage
- • Ellipse is near 4.6°S, 222.65°W (137.35°E)

- ellipse near 4.6°S, 22.8°W

- Bell *et al.,* 2005

- 20 km

- JFB: 5/31/06

## 5 km

- JFB: 5/31/06

## THEMIS-VIS V11330001

-    (7/4/04)
- • 18 m/pixel
- • 16:55 LTST
- • Depositional fan fills about half the ellipse
- • Relatively smooth unit
- • Fan materials were transported through the valley in crater wall (upper left)

- 5 km

- JFB: 5/31/06

## EDL and Trafficability/Traverse

- Edgett considered all possible places for landing ellipse in Gale Crater; Northwest fan ellipse seems like best location
- Landing might be challenging, but potential landing and traversing hazards appear (initially) no more problematic than at the MER-A site in Gusev Crater...
- The fan is not the primary scientific goal, but appears to be a safe and interesting place to land
- Fan could be a possible highlands “grab bag” site (also sampling ancient pre-Gale crust?) for initial scientific investigation; Possible lava on Gale floor, as well.
- Trafficable routes into the mound identified in MOC images
- But Gale is not JADPCL:
- A proposed traverse from the ellipse to the mound would utilize the “Go-to” capabilities of MSL to access to some of the diverse, sedimentary rock section in the mound.

- JFB: 5/31/06

## Possible Traverse Goal:

- “Grand Canyon” of the Gale Mound;
- 500-1000 m of exposed layered sedimentary rock, cross-section of lowest element of Gale stratigraphy;
- Canyon ~1 to 1.5 km wide.

- 3 km

- JFB: 5/31/06

**Notes:**
Probably too rugged for MSL traverse, but worth thinking about--- 

## Summary

- Gale crater and its central mound of layered sedimentary rock represent an important enigma in our present understanding of Mars
- Are the layers sedimentary?  If so, how were they transported there? (wind? water?) Why is the central mound so “rhythmically” layered, and higher than the rim/plateau?
- Outstanding place to test habitability of early Mars
- We believe that the site meets the EDL, Trafficability, and Planetary Protection requirements of the MSL Project, although the most interesting geological areas will require a drive from a nearby landing site.

- JFB: 5/31/06

## EXTRAS

- JFB: 5/31/06

## Gale Crater topography

- Transverse Mercator contour topo map from the MOLA 128ppd gridded data.
- (Tim Parker)

- JFB: 5/31/06