Mars, with a diameter of about half that of Earth, would have a horizon about the square-root-of-1/2 away, about 70%. If the horizon is 5 km on Earth for eyeballs 2 m high, it would be about 3.5 km on Mars. That's not dramatically different.

I doubt you could notice such a difference in pictures. The apparent distance on Mars would be further influenced by different atmospheric conditions, different height of the rovers' pancams from your eyes, and a lack of recognizable depth cues given by familiar objects of known size.

Straight answers from NASA: Earth's horizon and Mars' horizon

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interesting one.

Nice article on CNN.com about the two (Earth) year anniversary of the rovers.

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What was the topspeed of the marsrovers? And why are they driving so slow?

What is the top speed.

They are solar powered, and controlled by AI and non-realtime commands. The solar power means little power is available to use on driving (you need energy to perform science, power the cameras to see where you're going, power the onboard computers, power your heaters etcetc), the control means that there's nobody around to quickly change route when dangers suddenly lies ahead of the wheels.

Consider the moon rover from the apollo missions: it had precharged batteries, was used to drive and was controlled by the astronaut. (almost) All power could be used to propell the rover, and the astronaut took care of avoiding danger. Furthermore, large precharged batteries were available from which the motor could drain energy, not small solar powered batteries that need to find time to charge themselve somewhere during being drained .

I'm sorry this explanation isn't too good, but the fact that they're solar powered, energy is needed for a lot of things and they aren't human controlled in real time limits speed.

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From here

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10 mm/second is 0.036 kilometer/hour or 0.022 miles/hour

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Scientists relish Mars' images

After 2 years, rovers continue to beam back data

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MOC View of Spirit Rover on Husband Hill

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134000 images, 16GB of data, super high-res pictures, moving robots, working for 2 years, climbing hills, descending into craters, investigating fresh meteorites...

I wonder if ProjectOrion still thinks the Viking landers were so much more potent than the twin rovers.

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What's the consensus on finding evidence of water in the past now? Recently there were some claims that there is no such conclusive evidence.

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NASA Opportunity Mars Rover Image: 'Festoon' Pattern in Meridiani Outcrop

This is considered a strong sign of past water.

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Wow. The technological feat is magnificent but this sure does illustrate how time goes by so very fast. I can't believe it has been that long already!

I am following the Mars Exploration Rovers -- and this thread! -- with interest.

I remember jumping for joy as I watched the respective Rovers successfully land, unfold, and roll off their base stations. I can hardly believe it's been so long since these plucky robots first began their sojourn on Mars. How times flies!

The science that the Rovers has produced is nothing if not astounding to me. Looking at the photographs beamed back to Earth, I find myself marveling that they are of an alien planet millions of miles away, and yet crystal-clear and magnificent in every way. And the fact that scientists have discovered from the Rovers' journeys strong indications that areas of Mars were once covered with a shallow, briny sea only makes me wish we could do even more to explore the Red Planet. And, if our luck holds, we may, yet. We might soon explore it in person.

Every bit of news about the Rovers brings us knowledge of the previously unknown. But equally important is the effect that this continuing project has on many members of the public. Some people are inspired by poetry, some by music, and still others by song. Those things inspire me, too. But there is nothing quite so stirring as the realization that what we are doing now on Mars -- seeing strange places among the stars that no one in history has ever seen, almost as though we were all there -- is both the culmination of our pioneering spirit, and an evocation of the great things that may yet come to be.

Bring on the news of what humanity has accomplished so well in the name of science. Bring on the news of Mars, and the future.

Bravo, MER! Bravo, JPL! Bravo, NASA!

the orbiters have been great, Mars Odyssey, MarsExpress and MarsGlobalSurveyor
http://themis.asu.edu/zoom-20060109a
http://antwrp.gsfc.nasa.gov/apod/ap040124.html
One Mars Orbiter Takes First Photos of Other Orbiters
http://mars.jpl.nasa.gov/newsroom/pr...20050519a.html

A lot of people use the NASA and JPL sites to check out the photos


http://qt.exploratorium.edu/mars/opp...CP1110L0M1.JPG
http://qt.exploratorium.edu/mars/spi...WP1312L0M1.JPG

but some fantastic pics can also be found here at the exploratorium page

The world used to get smaller due to technology, it seems like it is getting a lot bigger now

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Great post, AstroReader! I think it mirrored the ideas and feelings of a lot of us.

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I think the big reason they're still rolling is the unexpected side effect of the dust devils/wind cleaning the panels off. Its been pretty remarkable how cooperative Mars has been while they've been in operation.

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Indeed. I mean, what would have happened had the water risen again?

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Good summary of rover status from The Planetary Society:

Spirit Heads to Home Plate as Opportunity Finally Roves On

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Spirit has arrived at the base of Homeplate
http://qt.exploratorium.edu/mars/spi...0P0685R0M1.JPG
http://qt.exploratorium.edu/mars/spi...0P2363R1M1.JPG

When the rovers do stop operating, do you think they will recover them when we go to Mars and place them in a museum or anything? I would like that very much if they did, although it won't be in my life time.(likely)

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I think they should be left where they belong.

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yeah, i agree. samething with the voyagers, pioneers and NH (if we have technology to recover them in future)

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Bountiful layering at Home Plate, seen by Spirit Navcam

More at Exploratorium :: Spirit :: Navcam :: February 7

A Pancam Shot of the Target-Rich Environment

More at Exploratorium :: Spirit :: Pancam :: February 7

It's too bad Spirit can't linger here for months of study, but before too long it has to head for the hills, out of the shadowy valley, and onto more energy-favorable slopes for the upcoming winter. I think they were planning to be at McCool hill in about 50-60 more sols.

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Wow! That's some really interesting looking geology. (Marsology?) Anyhow, gorgeous rocks. It'll be interesting to see some commentary on this.

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^
Try "areology."

Those are incredible rocks--check out that bedding! It could give Meridiani Planum a run for the money any day. I know Squyres is going to lose sleep over this; so many targets, so little time...

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Notes from the Spirit World and the Land of Opportunity

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Spirit Mars Rover Reaches 'Home Plate': Formation Has Researchers Puzzled

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Is the speck in the "sky" in this photo an artifact or a moon (or comet/asteroid etc...)?

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It's not in the right-hand image taken at the same time, so it has to be a camera artifact.

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