Spirit Sol 170

We're back in the phase where we start sequencing before we have the downlink -- that is, we're planning the next sol before we've seen the results of this one. We're still in that state when I arrive, and the problem is exacerbated due to some kind of downlink delay.

We might have something interesting to look at when the data comes in. Based on some soil analysis they've been doing, Larry Soderblom says that we might have actually pushed hard enough on the rock to push it into the surface. (Apparently, this started as a joke some scientists were playing on Ray, and then they realized it might actually be true.)

It's been a long time since I've been around for the downlink. I'd almost forgotten that it's fun and exciting. There are usually several people looking at different data sources, each of which provides different hints about what's going on, and part of the fun is competing to be the first person who can authoritatively say what happened.

This time's a classic case. If all went well, we should see signs that we successfully RATted, and the APXS should be planted in the RAT hole. "The active tool is the APXS," Rich Petras points out. "No red alarms. We're good." But this doesn't necessarily mean that the RAT succeeded -- most common kinds of IDD failures automatically preclude further IDD motion, but not the RAT; even if the RAT fails to drill a hole, the IDD will usually proceed with its work.

Leo Bister, watching the EVR stream (a running list of status messages from the spacecraft), asks us about a message that indicates a failed RAT placement. "Are we in trouble?" Maybe, maybe not. Bob Bonitz, who's hanging around for the fun of it, says that we get those messages sometimes even on success. They're generated as the RAT tries to find the surface it's going to drill into, and can just mean that it hasn't found anything quite yet, not that it's given up.

We go through a couple more cycles of hope and dejection before the full, complex picture emerges. Bob, reading carefully through the full list of RAT EVRs, works out that the RAT did make contact and start to grind, but not for long -- maybe for only 20 minutes or so, out of a planned two hours. Then the RAT lost contact and gave up.

The reason for this becomes clear when we get the images back. Larry was right: we pushed the rock into the surface. Because the RAT was placed slightly off center, the rock actually rotated: the left side of the rock got pushed in, and the right side came up. (We attacked, and the rock turned tenkan![1]) The right-hand side brought some crusty soil up with it, like mud clinging to a shoe. There's no visible damage from the RAT -- we don't seem to have so much as scratched it.

The rock has foiled us again, or at least fought us to a draw. "'Pot of Gold?' Chris remarks sardonically. "More like 'Pot of Crap.'" He later has to pick a target on the rock for further IDD work, and he names it "Fool's Gold."

Scott Doudrick is similarly sour. He asks if we can use the IDD to flip Pot of Gold the bird as we drive by -- "the L.A. driving experience," he says. "For the true L.A. driving experience, we'd have to shoot at it," I remark.

Later, it turns out that we hurt the rock more than we thought. Larry Soderblom goes off and takes a more careful look at pre- and post-RAT images, and discovers that there is some visible change. Some of the irregularly shaped "fingers" broke off, and the RAT's outer ring truncated a couple of high points on the rock, leaving behind shiny clean surfaces, when we pushed the RAT down hard. (We always do this when we're about to grind, so that the RAT will stay firmly connected to the rock surface. Curiously, the sequence of images we took during the RATting shows that it wasn't this initial push that forced the rock into the surface; that happened later, maybe as a result of the grind-induced vibration.)

Squyres reports that we've done some other interesting damage as well. They've just discovered that the rocks we recently drove across are shiny (in the PANCAM's blue filter) where the cleats hit them -- so shiny, they saturate the image.

"What does that mean?" Doudrick asks him.

Squyres grins, deliriously happy. "I have no idea," he says.

Steve's quiet for a minute, staring at the image and shaking his head slowly. "Every day, it's something new and bizarre." He pauses again. When he speaks again, he voices a thought similar to one I've often had myself. "I feel like Mars is giving us our final exam," he says, "and we're not doing very well."

"It's been a long semester," shrugs Leo.

Despite our having had some limited success thisol -- for once -- the team continues to be jokingly superstitious about the nefarious power of Pot of Gold. Julie's trying to print some stuff out and go home, but she keeps being thwarted in the effort -- her (Windows) laptop is glitchy, and then when she turns on the printer (which wasn't supposed to be turned off), there are days' worth of other people's print jobs queued up, which all has to print out before she can print her stuff.

"It's this damned rock!" says Leo. Nobody disagrees.

[Next post: sol 175, June 30.]

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Courtesy NASA/JPL-Caltech. The RAT shoved Pot of Gold into the soil. Take that, you damned rock!

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Footnotes:

[1] An aikido joke. You are not expected to understand this. :-) But, if you're curious: tenkan.