EVA-11 Report
Kyoichi Sasazawa

Theme: Exploration of middle part of Morrison Formation

Duration: 11:20-15:41 3 hours 21 minutes

Participants: Diego Casa, Celeste Gale, Kyoichi Sasazawa (commander)

Equipment: ATV, camera, rock hammer, GPS, reflector, and map with waypoints

Route: in UTM

• Hab (0158.170E 4250.93N) to 0518.90E 4250.93N (Wpt 101) with ATV
• Wpt 101 to 0519.20E 4251.75N (Wpt 102) with ATV
• Wpt 102 to 0519.69E 4252.40N (Wpt 124) with ATV
• Wpt 124 to 0520.39E 4251.05N (Wpt 125) with ATV
• Wpt 125 to 0521.332E 4251.081N
• 0521.332E 4251.081N to Hab with ATV

Objectives/Work Done: The purpose of this EVA was to explore the northeastern igneous rock field and Candor Chasma, which exposes the middle-to-lower part of the Morrison Formation, its upper part is exposed at the Hab area. We proceeded to the edge of the gorge with ATVs, and then walked along the streambed of the gorge.

We confirmed the route to Candor Chasma and collected rock samples along the route. We also collected some samples of limestone at the gorge.

Weather: Clear, 46-50F

Maximum distance from hab: 3.17km.

Lessons Learned:

1. We need to pre-plan an ATV-possible route to Candor Chasma if we go down the pass again. The repeater was little help in the gorge.
2. Our recommendable physical limit for walking with spacesuits in sandy conditions, is about 2-3 kilometers per EVA.
3. We confirmed sequences of Salt Wash Member, middle part of Morrison Formation.

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EVA-12 Report
ATV Towing Test

Duration: 12:18-15:57 (2 hours 39 minutes)

Participants: Digby Tarvin, Bob McNally

Equipment: ATVs, Rope, Camera

Location: 4250.93N 0518.17E (Hab, and near vicinity of)

Objectives/Work Done: This EVA was conducted to evaluate towing methods for the ATVs, in preparation for towing training tomorrow. Two ATVs were linked by a 30 feet long, 1 inch diameter rope. We used two turns around the tie point, and two half hitches, not because these are the best knots, but because they are the knots most people would be likely to use, and we wanted to see if they would work. The best knot would be a bowline at each end. The tie points were the towing bracket at the lower rear of the towing vehicle, and the brushguard at the front of the towed vehicle. The tower was placed in low gear, and the towee in neutral. We experimented with various speeds, turning and braking techniques, and riding over moderate obstacles.

Weather: Clear and Sunny. Temp range 46-50 F

Maximum distance from Hab: 0.25 km

Lessons Learned: It is very workable to tow 1 ATV with another or to use 1 ATV to assist another stuck ATV. Starting slowly to minimize jerking loads is important, and keeping the speed slow to moderate is necessary because the second vehicle is quite close to the first. Careful concentration is required by both riders to insure there is not a collision from behind. Turning also requires attention, the rear vehicle should steer to keep the rope safely near the center, not near the tires, and avoiding running over the tow rope, as well as not colliding. Steering toward the inside of the turn helped center the towline, and that may require the tow driver to steer wide to allow the towee to turn more inside.

Moderately steep obstacles were attempted. This was successful, but it is not always possible to keep the towline from dragging over the ground when crossing a bump. This could pose fraying problems in rocky areas, so slow speed, caution, and looking ahead are necessary. It is also possible for the tow vehicle to come down off a bump and begin to climb another, while the tow vehicle is still climbing the first one, and bog down the tow vehicle. Shifting into four wheel drive is necessary for the tow vehicle in this situation. The rear driver is completely responsible for not running into the front vehicle, there is almost no realtime rearward visibility in space suits, even with wrist reflectors. It is recommended that the flattest, most obstacle free route be chosen, but it it good to know that more moderate terrain can be towed over. Practicing towing gives confidence that longer and more ambitious EVA may be conducted without worrying about a stranded ATV.