An impossible task? And maybe a not very useful one but...here it goes...

I would really like to establish a link between both rovers, Spirit and Opportunity.
How to achieve it?
Is there a way to find the X marking the spot? Phil? James? Pando?...Anyone?

Is there a way of, through your accurate measurements find a a way to Xitania and X Civitas? The martian ground wher both rovers meet?
How does this work? Nothing really scientific, maybe a mere curiosity but I would like to know where, grabbing both rovers landing sites and drawing a straight line between these and then, taking their current locations, find where the intesection point is located...that is what I would call the Xitania capital, X Civitas...is it feasible? Come on guys...I know that from you there are no impossibles...

Maybe we can this exercise into previous sols and, most importantly, future ones, until the last one of them...then we would have the whole Xitania territory marked, joining the four quadrants and X Civitas would be there, as a capital of a whole unexplored ground...please me!

How about just the lat and long values in the middle of the two lat and long values of the rovers.

Doug

Sorry for my eagerness and one beer beyond the acceptable but...is that accurate enough Doug?...

Imagine a square formed by Spirit's landing site and her current location and the same for Oppy, that's Xitania, and the point where lines meet that's X Civitas, impossible to acquire?

I would truly like to know where, exactly, those lines meet, I know...too demanding, but you guys have spoiled me...

Well, for starters you can take a look at this: http://en.wikipedia.org/wiki/Great_circle_distance

You've completely lost me.

Doug... I AM proud of that...

ugordan...why do you think I've asked for help on this?...Euclidean geometry?! My kriptonite!

Well, then, you're in luck! This ain't Euclidean geometry, it's spherical geometry!

Using an image from Google Mars, I marked two rectangles between Opportunity and Spirit where they could meet, depending on which way they go. Rectangle 1, to the West of Opportunity, looks to be in rough territory. Rectangle 2, to the East, looks good. That rectangle would have the added advantage that Opportunity and Spirit could join forces to look for Beagle which is located in that area.
Click to view attachment

If we're fantasising that they're capable of driving that distance I don't think a small matter of a range of honking great shield volcanoes and chaotic terrain would be much of an obstacle And Oppy gets to explore Valles Marineres ..! Ack, this is the second "fantasy Mars exploration" post from me today... I must try to stop daydreaming...

Ahh, daydreaming of Mars. Perhaps a "daydreaming" thread is a good idea, or, heck, even an entire subforum!

I've certainly dreamt of rover encountering rover. Just imagine a crazy alternate universe where their landing sites had been tens instead of thousands of km apart. Or if MSL were to go to Meridiani...

As they approached each other, one of us here at umsf would be the first to spot one from the other's cameras, nothing more than a single pixel glint of sunlight, a beacon on the horizon. Then, over very many sols, the single pixels would grow, and eventually the rover shape would be recognizable. Finally Encounter Day would arrive, and we'd see the rovers as no overhead projection or simulation could ever show. We'd see them on Mars.

You guys are crazier than this special cookie of yours!

I'm looking only for he interception point nothing more than that!

But we can discuss it...

I still think that, using Google Mars, it is a fun coincidence that Beagle 2 rests in a spot just about mid way between the MERs. Spirit, being a little hobbled would stick to the lowlands. (How Spirit would get out of Gusev, I don't know.) Opportunity could take a more direct route.
Click to view attachment

I vote for rectangle 1 because I think the "Labirintus Noctis" should offer a breathtaking view!

That's simply half way around the great circle path between them. But you seemed to dismiss that - seriously - I don't know what you're trying to get at here. Half way between them, or something else. What does a rectangle have to do with it? Both being fairly close to the equator, a great circle route is fairly close to just a straight line on the map anyway.

Spirit is 14.5718 south, 175.4785 east
Opportunity is 1.94 south, 354.47 East

Thus - a point roughly between them is 8.256 south 264.97 east, which is the east end of Noctis Labyrinthus.

If that's not what you're after - then what are you after?

By the way, B2 is only roughly half way between them - if you go the long way around. There's only 2 degrees in it - but the 'shorter' route is to go West from Opportunity and down Valles Marineris - not East between Hellas and Isidis.

Doug

Ido not understand why you want a route map going along the equator. There are two others by each of the pole. So there are 4 possible meeting points.

Actually since they are almost at opposite sides of the planet now, they could head towards any heading and meet along a great circle.

But the equatorial route is clearly the best, since the sun is higher more often at the equator.

Isn't this great - I'm mixing cold, hard, engineering realism with utter fantasy.

Because that is the shortest.

If they were on EXACT opposite sides of the planet ( 0, 0 and 180, 0 ) - then yes, you could infact leave one in any direction and if travelling in a straight line - you would then hit the other. BUT - they're not.

OK, got it! But, as you said yourself Doug, "what are we after" anyway?
This topic is just out of this world

Of course, I'm making the mistake in thinking of Mars as a sphere, which it isn't. Oblate spheroid and all that

You're right, it's far from it:
Click to view attachment

Given that:
1. The solar powered MERs must stay close to the equator for what would be a journey of many Martian years.
2. The rovers are not exactly on opposite sides of Mars.

Then, yes, there would be one curve on the surface of Mars that would mark the shortest distance between the two rovers as the bird flies. And it would be interesting just out of curiosity to know where that route was, along with its center point. But if you want to be a little more realistic ( ), you would take into account the state of each rover and the terrain each would have to cover to determine the most likely area in which the two would meet.

Two different things: One, a mathematical curiosity and the other a fanciful "what if they could do it" scenario.

From where did you guys pull out the idea of calculating a path for rovers to meet?!

Not from me...

I was just curious about if it was possible to know how to calculate this precise location on martian ground:
Click to view attachment

Nothing more than finding a X, with no further implications, just plain curiosity...

Well - they've both travelled south - so a line between the two landers wouldn't cross a line between the two rovers. In your drawing, one goes up and one goes down. In reality - one's gone down, and one's gone down and right.

The distance covered by both rovers is noise compared to the distance between them. It's about 10,500 km between them. From Spirit's position - the total traverse of Opportunity, call it 7km, extends only 0.038 degrees.



"grabbing both rovers landing sites and drawing a straight line between these and then, taking their current locations, find where the intesection point is located" - this now makes sense - but now that it makes sense....it - errrr - doesn't make sense because they're both the same side of the line between them

This drawing doesn't have the scale - but relatively - it demonstrates how and why your two lines wouldn't cross one another.

Had Spirit, for example, driven North, not south - then we might have an X - but we don't.

Hard to demonstate but I think, for an observer on the Earth, the lines crosses while Mars is rotating. Right ?

I can't really imagine how - they're so close, and so very nearly parallel, they might as well just be one line. And even if they did - it would be a dynamic 'apparent' crossing, not a real one.

Well, if you're going to drive all that way, may as well make it a party by meeting up at the Viking 1 lander site.