February 4th, 2010:

(continued…)

Brian showed me how the software worked so that I could help him prepare it for shot data collection. We had to update the current position each time Luis moved, and update the position of the land streamer each time we advanced it. It was good to have two people who could operate the software, because Brian’s helmet fogged up so that he couldn’t see the laptop screen. So we both hunched over the laptop, under the ATV cover we’d brought up with us to use like a photographer’s black drape. We poked at the laptop keys with two pens, since the suit gloves aren’t dextrous enough to hit the keys accurately.

Brian, Luis, and Darrel had previously worked out a system of hand gestures to communicate while collecting data, because we had to turn our suit radios off (they could cause interference with the data collection). So I’d enter the coordinates, Brian would wave vertically to Luis, Luis would swing the hammer, the laptop would beep happily when it detected the shot, and we’d repeat. When three good shots were collected, Brian would wave his hand horizontally and Luis would advance to the next location. I’d disarm the geophones while Luis moved, then re-arm them once he was in position again.

One thing we had not anticipated was how quickly running the laptop from the ATV’s battery (via an inverter) would drain the battery. After a couple of hours of data collection, the next time we tried to tow the land streamer, the rover almost wouldn’t start. Duh! Of course you need to run the rover for a little while each time and let it charge the battery. We didn’t have trouble after figuring this out.

Soon we’d settled into a great routine and were collecting shot data with high efficiency. Near the end of the sixth line, though, I noticed that the sun was touching the far horizon, and we decided that we’d have to stop at the end of that line. We finished the shots and started packing up as quickly as we could. At that point we realized that we were somehow short on bungee cords—and two snapped while we were strapping them on. So things weren’t as secure as we would like. Also, Luis was the only one with a headlamp, which was a bad oversight on our part.

It was nearly dark by the time we started for home. But our rovers have great headlights (if they didn’t have lights, we obviously wouldn’t have stayed out so long). In fact, visibility wasn’t a problem at all, and it felt perfectly safe heading home. The problem instead was with the strapped-on equipment. I had the laptops in a hard case strapped on the front of Spirit, but they were resting on that wretched heavy metal plate we used for shots. The plate was both smooth and had snow on it, which was a recipe for a very low coefficient of friction. Plus, the bungee cords weren’t really strong enough to hold the laptop and the plate in position. So every little bump in the road was causing the case to slide around. I started holding the case with my left hand and driving with my right (where the throttle is) but this definitely is not ideal on an ATV. Finally, after crossing an unusually bumpy mini-gully, I felt the case slide more than usual and decided to stop. I guess Luis was close behind me, because his rover bumped into mine (but not hard).

We climbed off and fiddled with the bungee cords. Brian, who had been in the lead with a faulty radio, finally realized that we weren’t with him and turned around and came back. We strapped the laptop case on the back of Spirit (on top of the sledgehammer) and set off again. This was much more secure, and the driving went more smoothly—until the plate started moving on its own and I realized that its bungee cord had popped one end off. I stopped (no impact this time), reseated the cord, and headed off again. This happened a second time. The third time, I was heading into a ditch and the plate slid off the front of the ATV. I let it go, since unlike the laptop case it wasn’t worth diving for to save. I stopped, climbed off, picked it back up, and Luis and Brian strapped it more securely. We then cautiously motored home, our speed limited far more by our burdens than the night conditions. Luis and Brian also had challenges—the bulky geophone boxes strapped on the back of the ATVs prevented them from fully sitting down, because our suit packs stick out so far behind us.

You can view the full EVA 18 information, including a map.

We arrived back to the Hab at 6:45 p.m., and never was that airlock so welcome! Darrel and Mike were waiting inside and helped us out of our suits. We removed packs, helmets, radios, gloves, hats, gaiters, boots, cameras, GPS units, etc. and climbed wearily up to our living quarters. Thank goodness, Carla had a hot meal waiting for us on our return!

I spent half of today up on Radio Ridge assisting with Brian’s seismic survey. He’d gone out yesterday with Luis and Darrel to start the survey, but they’d had their EVA truncated when the Panasonic Toughbook they were using fell off the ATV and yanked the Ethernet port entirely out of the PCMCIA card, rendering it inoperable. Worse, when they returned to the Hab, we discovered that none of the data they had collected had been saved to the hard drive! Brian handled this disappointment stoically, however, and planned a second attack for today. In yet another feat of gosh-wow on-the-fly problem solving, Darrel was able to solder the connections back together (!) and fix the PCMCIA card (I had been certain it was toast!). But then, to make things even easier, he donated his own laptop for use on the survey today. We took both laptops, just in case.

Brian knew from his EVA yesterday that this process would take some time, so he was itching to get going early. We all were. I’d volunteered to join the EVA out of curiosity (I’ve never studied any geophysics or seen seismic work in action) but also because Brian clearly needed some helpers. Luis and Darrel were worn out from yesterday, but Luis agreed to come along as well today—and ended up doing the lion’s share of the physical work in the expedition. But I’m getting ahead of myself. Although we were hoping for an early start, somehow it just took a long time to get everything together, strap all the equipment onto the ATVs, and get suited up. We didn’t enter the airlock until 12:30 p.m., and then Brian realized that in our rush he’d missed his helmet bungee cord… so we waited to re-pressurize, he got his helmet fixed, and then after a 5-minute wait we were finally stepping out into the noon sunshine. It struck us immediately, right in the face (our helmets don’t have visors).

We saddled up, me taking Opportunity for the first time (I’ve always ridden Spirit previously). Opportunity is supposed to be the easiest to drive, because it’s the only one with a thumb-button gearshift (the others have foot-pedal clutches). But having gotten used to Spirit, it took me a while to get the hang of thumb-shifting. We took off across the desert, and my second lesson of the day struck. My previous ATV EVAs almost exclusively stayed on Lowell Highway. This time we were on a side trail—narrow, twisty, bumpy, and an entirely different riding experience! There were a few times that I thought to myself, “This is a ROAD?!” but there they were, twin tracks in front of me, leading the way. So I came up to a half-crouch and rocked with Opportunity, absorbing the jolts and bumps, standing up on the up-hill sections to lean forward and aid in the climb. It was more lively than the road drives—and I must say, a lot of fun! It’s funny how the ATV feels much more than a machine beneath you—more powerful, more animal, more alive.

We came up onto Radio Ridge, and I gasped with delight and awe—the valleys and hills fell away from us to the right, in colored bands and dappled with sparkling, shining snow. I hadn’t seen the sun out in its full glory in days. It was shining and sparking off every rock and bush. Mid-ridge Planitia spread out before us to the west, all the way to Skyline Ridge in the distance (now THAT looks like fascinating geology). We headed south to the seismic survey site, and I was bouncing and revving along in utter delight. There was a drop-off to our left that plunged back down to where the Hab is situated, and we stopped several times along the way to snap pictures of the awesome panoramic view. Since I had the camera, Brian urged me to say the word if I wanted another picture stop. “Only if you think we have time,” I said, since our main goal was to collect the seismic data, and we were late off the mark. “We probably won’t want to do it on the way back,” he said, and boy, would he be proven right.

We reached the site and Brian hooked up the laptop to the land streamer (12 geophones strung on a 55-foot cable). That’s when it really hit home to me how much work yesterday’s crew had done. Although they hadn’t gotten any data, they’d done all the surveying and marked out a 300-foot line in 30-foot increments, enabling us to just walk to the appropriate point without having to check GPS coordinates or mark anything ourselves. (The distances are in feet, by the way, because the geophones are spaced at 5-foot intervals.) We could get straight to work.

Still, it took us a while to fall into a rhythm. The way this survey works is that you lay out the land streamer, pressing each of the geophones into the ground, and then position a heavy metal plate at key points; you then swing a heavy sledgehammer and smack the plate repeatedly (each such blow is a “shot”). The laptop records the response from each geophone for each shot, and after collecting data from six shot locations, you then connect the land streamer to an ATV and drag it 55 feet further along the line you wish to survey. We did this six times. Luis turned in a heroic effort with the sledgehammer, doing almost all of the more than 120 shots himself.

We also saw mountain lion tracks!

(Stay tuned for part two… WordPress won’t let me put it all in one post!)