The seeing is good. Spirit caught this spectacular view looking southwest towards the far away rim of Gusev crater. The robot is nearing the summit of Husband Hill in the Columbia Hills, also catching more glimpses of fleeting dust devils racing across the landscape. Image
The Spirit Mars rover is within striking range of attaining a once out-of-the-question mission milestone: Reaching the summit of Husband Hill at its Gusev crater exploration site, high in the Columbia Hills, named after the astronauts lost in the tragic shuttle reentry accident of 2003.
"I'm going to go out on a limb and say that I think our chances of making it to the summit look pretty good now," said Steve Squyres, lead scientist at Cornell University for the Mars Exploration Rover effort.
"We're about to start naming rocks up [t]here after famous mountaineers," Squyres told SPACE.com, "so that gives you a little insight into our mind-set!"
Squyres, as well as Chris Leger, one of Spirit's main drivers, are both climbers.
"So on a gut level we'd really like to get to the summit," Squyres said. "And the scientific case for going to the summit is very solid. But we're doing mountaineering for which there is no precedent. So I've been trying not to get my hopes up."
Squyres said the terrain facing Spirit has been very solid of late, and the driving has gone well.
On the other hand, scaling Husband Hill has been slow going, primarily due to the rich bounty of observations on the way.
"We'd go a lot faster if the science weren't so good! The upper reaches of Husband Hill are turning out to be a remarkably target-rich environment," Squyres added. As example, a "fabulous new outcrop" dubbed "Voltaire", he said, "doesn't look like anything we've ever seen before."
Voltaire has received close inspection by the rover's science instruments, Squyres said, prior to resuming the summit assault. "It's just too interesting to pass up."
From Spirit's vantage point at the summit, what kind of outlook can be expected?
"Hard to say," Squyres responded.
"We should get a good view to the horizon in all directions, which should be pretty spectacular. I think, however, that it might be hard to get a really good look in all directions at the lower flanks of Husband Hill itself," Squyres said.
Not only is the summit pretty rounded, Spirit itself isn't very tall.
"So we may have to proceed down the south side of the hill a little way before we'll be able to say much about what's on the other side," Squyres said.
Finding the right balance
Spirit is making "discovery after discovery" on Husband Hill, Squyres said in a recent update on the Cornell-based Mars rover website.
The close-at-hand reaching of the summit - after lengthy bouts of the robot slipping, sliding, and clawing its way up the slope -- has sparked discussion within Spirit's science team, Squyres remarked.
"The strong feeling on the team is that we should try to go for what we've been calling 'Summit 2'...which is both closer to us and a little bit higher than Summit 1," Squyres reported.
With Spirit's imminent arrival at the select pinnacle, rover scientists will probably want to take a fairly substantial panorama there, then wheel down onto the lower flanks of Husband Hill, Squyres said.
It has been an interesting time working on Spirit these days, Squyres added, "as we try to find the right balance between our eagerness to get moving up the hill and our excitement over all the new stuff we're finding at Voltaire."
All looks good for reaching the summit in short order, said Larry Crumpler, a Mars rover science team member and a research curator in volcanology and space sciences at the New Mexico Museum of Natural History and Science in Albuquerque.
"The plan is to start driving in a southeasterly direction toward one of the summits, the exact one being determined after we get a look at the terrain ahead," Crumpler told SPACE.com.
In terms of the significant events or "arrivals" during Spirit's mission, wheeling up to the summit "probably ranks as one of the greatest," Crumpler explained. "This will be one of the biggest events in the mission."
Crumpler said that arrival at the summit within the Columbia Hills marks the end of Spirit's long climb that has been underway since sol 330, or about 230 sols ago - with many stops along the way. A "sol" (Latin for "sun") is the Martian equivalent of a day in reference to the planet's period of rotation.
Spirit landed on Mars at Gusev crater in early January 2004. Its sistercraft -- the Opportunity rover - touched down a few weeks after Spirit and is busy trekking about Meridiani Planum on the other side of the planet.
Reaching "Home Plate"
Claiming victory in getting to the summit will depend on whether some "utterly compelling target" shows up en route, Crumpler advised. "The desire is to get to the summit, do what needs to be done there, and start heading down as soon as possible."
"At the summit we will probably spend some time doing a large panorama," Crumpler said. "One of the goals there will be to take a hard look at the basin to the south where one of the long-term targets of interest -- 'Home Plate' -- is located. Specifically we will want to see what the best route might be."
Crumpler advised that there is some fairly steep terrain on the other side of the hill that Spirit will have to descend, so finding the best path is a top agenda item.
"One of the considerations is that many of us would like to get a look at the possibly layered terrain on the east side of the basin on our way to Home Plate," Crumpler said. Yet another factor is the distance. Home Plate is roughly a mile away from Spirit's current location, which may take a few months of driving.
"In a couple of hundred sols we will need to start considering the decreasing elevation of the Sun again," Crumpler said, "so it would be nice to have north-facing slopes available either before or after reaching Home Plate."
Crumpler recalled that, shortly after Spirit touched down, there were longing looks at the Columbia Hills in the distance. At that time, talk of possibly wheeling the robot to that faraway geological feature was typically met by laughter, he said.
"None of us thought we would ever be in the hills, let alone be on the summit," Crumpler concluded.
The Mars Exploration Rover work is yielding a wellspring of science data, Squyres said, stressing that point in his just released book: Roving Mars - Spirit, Opportunity, and the Exploration of the Red Planet (Hyperion Books, August 2005).
In the book, Squyres writes about the melding of humans and far-flung machines to study Mars...of sending robotic surrogates for human explorers into an unknown environment on a voyage of scientific discovery. "The key is not just to follow the robots, but to follow the intense and passionate people who conceived and built them."
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- Mars Rover Special Report