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#200
by
robertross
on 18 Aug, 2012 13:42
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What is that concave feature on the ridge of mount Sharp (or on the mound), which I've circled?
The enclosed image cut comes from the panorama here:
http://www.planetary.org/blogs/emily-lakdawalla/2012/08171906.html
Also, I wonder if there is any panorama around with a bar at the bottom which indicates the direction in degrees in which one is viewing? I'd like to pin point where in the panorama above, for example, Glenelg is located. I would now guess that it's slightly to the left of where the shadow of the mastcam points.
It's just the effect of the blurry background. The whole top of the ridge is fuzzy, and it's only because you have a high contrast area with that dark area (likely due to a depression) that it shows up that way
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#201
by
hop
on 18 Aug, 2012 19:21
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It's just the effect of the blurry background. The whole top of the ridge is fuzzy, and it's only because you have a high contrast area with that dark area (likely due to a depression) that it shows up that way
Actually, it's a piece of the rover that was photoshopped out. The mountain in that stitch was from the early hazcam shot. Description here:
http://www.planetary.org/blogs/emily-lakdawalla/2012/08171906.htmlDamien Bouic has stepped into the breach, doing his best with the only photo we have that reaches the mountaintop: the one taken by the rover's forward Hazard Avoidance camera on the day of the landing. It's a wide-angle, fisheye camera, so the view is pretty low-resolution, and there's a divot at the right side where a piece of Curiosity obstructed the view.
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#202
by
jumpjack
on 20 Aug, 2012 18:52
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Sorry for not reading all previous 14 pages,but I have a question:
why is rover white?? Last thing we need on Mars is COLD, so why didn't they paint the rover black, to gain some °C without needing electricity?
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#203
by
Kaputnik
on 20 Aug, 2012 19:02
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You are correct that a darker colour absorbs heat more easily, but it works both ways and it will also lose heat more quickly.
A lighter colour both absorbs and emits less heat over the course of a day, which makes thermal regulation of the rover easier.
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#204
by
iamlucky13
on 21 Aug, 2012 23:06
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Sorry for not reading all previous 14 pages,but I have a question:
why is rover white?? Last thing we need on Mars is COLD, so why didn't they paint the rover black, to gain some °C without needing electricity?
Overheating is as much of a danger as freezing to death - they have to design not only for the coldest temperatures the rover will encounter in the dead of winter and dark of night (when the sun is no help anyways) but also for the hottest temperatures it will encounter at high noon in the summer.
It's often technologically easier to add heat than it is to get rid of it, especially when you already have a 2 kW heater for a derriere. While parts that sit outside the body like the wheel motors, and mast and robotic arm instruments require electric heaters, the rover body itself is plumbed into the cooling loop for the RTG and can adjust the flow of heat into the body as necessary. It's practically free heat.
Bonus question - What color are the robotic arm joints and turret and wheel motor covers on MSL?
Hint:
http://photojournal.jpl.nasa.gov/catalog/PIA15277(I can't confirm authoritatively that the different thermal control requirements are the reason, but I strongly suspect so).
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#205
by
Jim_LAX
on 17 Nov, 2012 16:50
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Question: Since MSL's RAD instrument has revealed that surface radiation levels at Gale crater are comparable to those on the ISS in Earth orbit, could Lichens from Earth survive (and produce oxygen) there? I know they survive freezing here on Earth but a cold winter's night on Mars would be much colder, even in the Martian tropics.
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#206
by
fthurber
on 20 Nov, 2012 02:21
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Question: Since MSL's RAD instrument has revealed that surface radiation levels at Gale crater are comparable to those on the ISS in Earth orbit, could Lichens from Earth survive (and produce oxygen) there? I know they survive freezing here on Earth but a cold winter's night on Mars would be much colder, even in the Martian tropics.
It might be too dry. The extreme aridity and negligible atmospheric pressure would desiccate any surface organism not to mention UV and perchlorates.
But it is an intriguing question. I think a good place to start might be the Dry Valleys of Antarctica or the Atacama Desert. Lichens barely survive in the Dry Valleys and grow very slowly (on the order of .01 to .005 mm/year). However Mars is a much tougher environment.
Were thinking in terms of terraforming? Extreme patience would be required using lichen...
I believe that lichen can even dissolve rock (with an organic acid) and contribute to soil growth but even on Earth this is very slow.
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#207
by
scienceguy
on 20 Nov, 2012 03:49
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Question: Since MSL's RAD instrument has revealed that surface radiation levels at Gale crater are comparable to those on the ISS in Earth orbit, could Lichens from Earth survive (and produce oxygen) there? I know they survive freezing here on Earth but a cold winter's night on Mars would be much colder, even in the Martian tropics.
Researchers in Europe have studied this. The lichen Xanthoria elegans has been taken to the ISS and left outside in the vacuum of space and it still photosynthesized when it was brought back and warmed and wetted.
http://en.wikipedia.org/wiki/Xanthoria_elegans They also had this lichen in a chamber simulating Mars conditions and found that it photosynthesized, albeit for a couple of days. It was determined that Mars is too dry for this lichen.
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#208
by
scienceguy
on 20 Nov, 2012 03:54
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Xanthoria elegans survived for 4 days in Martian conditions. Here is the reference:
De Vera, Jean-Pierre. (2012) Lichens as survivors in space and on Mars. Fungal Ecology 5:472-479
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#209
by
hop
on 20 Nov, 2012 05:43
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#210
by
Robotbeat
on 20 Nov, 2012 13:18
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#211
by
ClaytonBirchenough
on 05 May, 2013 10:50
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What would the payload be if MSL were to land at an area that was -7km MOLA?
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#212
by
ClaytonBirchenough
on 12 Aug, 2013 21:05
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I know this is an old thread but I've got a question that has been "urking" me...
So prior to parachute deployment, MSL ejected six tungsten weights (each 25kg) as a ballast. My question is why six? Why not one 150 kg ballast?
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#213
by
Jim
on 12 Aug, 2013 22:12
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I know this is an old thread but I've got a question that has been "urking" me...
So prior to parachute deployment, MSL ejected six tungsten weights (each 25kg) as a ballast. My question is why six? Why not one 150 kg ballast?
Bring the the cg to the center of the vehicle and easier to attach to the aeroshell
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#214
by
ClaytonBirchenough
on 12 Aug, 2013 22:19
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Bring the the cg to the center of the vehicle and easier to attach to the aeroshell
Six tungsten ballasts were easier to attach to the aeroshell than one ballast?
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#215
by
Jim
on 12 Aug, 2013 22:27
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Bring the the cg to the center of the vehicle and easier to attach to the aeroshell
Six tungsten ballasts were easier to attach to the aeroshell than one ballast?
The aeroshell is composite.
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#216
by
baldusi
on 12 Aug, 2013 22:40
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Bring the the cg to the center of the vehicle and easier to attach to the aeroshell
Six tungsten ballasts were easier to attach to the aeroshell than one ballast?
The aeroshell is composite.
Volume, local attachments strength or balance issues?
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#217
by
hop
on 13 Aug, 2013 02:20
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Bring the the cg to the center of the vehicle and easier to attach to the aeroshell
Six tungsten ballasts were easier to attach to the aeroshell than one ballast?
Yes, if you want to be able to eject them cleanly and maintain the desired CG.
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#218
by
JohnFornaro
on 13 Aug, 2013 15:01
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Imagine being on a falling hexagon and throwing a 150 kg weight overboard.
Now imagine being on the same falling hexagon and throwing (6) 25 weights overboard in a hexagonal pattern.
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#219
by
ClaytonBirchenough
on 13 Aug, 2013 17:22
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Imagine being on a falling hexagon and throwing a 150 kg weight overboard.
Now imagine being on the same falling hexagon and throwing (6) 25 weights overboard in a hexagonal pattern.
I'm imagining... were the ballasts ejected all at the same time?
