Download and install Blender ( http://www.blender.org/ )

Import OBJ

Export STL.

Done.

(Caution - you will not want to try and print an object like this on a 3D printer as-is. You will need to bifurcate it into hemispheres - such as I've done for other small bodies like Eros, Itokawa and Vesta http://nasa3d.arc.nasa.gov/search/ellison/model )

It's alive alright.

There are some great articles on that at the JPL Tech Report Server...

The Spirit anomaly story : http://trs-new.jpl.nasa.gov/dspace/handle/2014/38849
The Mars Rover Spirit FLASH anomaly : http://trs-new.jpl.nasa.gov/dspace/handle/2014/39361
Mars Exploration Rover Spirit Sol 18 anomaly : http://trs-new.jpl.nasa.gov/dspace/handle/2014/40546

It's a rover issue.

http://www.jpl.nasa.gov/news/news.php?release=2014-292
An increasing frequency of computer resets on NASA's Mars Exploration Rover Opportunity has prompted the rover team to make plans to reformat the rover's flash memory.

The resets, including a dozen this month, interfere with the rover's planned science activities, even though recovery from each incident is completed within a day or two.

It is imperative to not do something that is likely to get the rover permanently stuck. Driving into areas with questionable traction without autonav & visual odometry etc is significantly more likely to result in a permanent embedding event that would bring the mission to a premature end.



Just because you don't see them doesn't mean they don't exist. It's been explained why driving in the dark would present an entirely unnecessary risk to the vehicle

MastCam can not be used for AutoNav.

MastCam will not see anything in 'starlight'

Moreover
-The MRO pass would not be long enough for an in-the-loop driving decision process.
-Earth may well not be visible during a night time MRO pass at Gale.
-The energy required to warm the mobility system to do this would be huge (if not entirely insurmountable)
-What evidence is there that 'cool' sand dunes offer more traction?

The Haz and Navcam's are not IR cameras. They can not see in the dark.

https://www-robotics.jpl.nasa.gov/publicati...ne/fulltext.pdf

Their sensitivity is between 600 and 800nm. Thermal IR starts at 3,500nm

What is a 'realtime overhead data link'? Are you talking about returning data from MRO? That only happens for about a 15 minute period, twice a day, and the one-way light time is usually more than the duration of an MRO pass.

How would you conduct hazard avoidance in the dark? How much extra energy would you be spending heating the mobility system to allowable temperatures before moving?

And moreover....why might it be better at night anyway? I've attempted to drive across the sand in 40degF heat and 105degF heat....didn't change a thing.

I have a hard time imagining it will ever be that small. That would require us knowing the location of the orbiter to an accurate barely wider than its own solar panels, and it's distance to the comet similarly accurately, AND the gravity gradiant all the way to the surface in a free-flight that might take anything from 2 to 12 hours. There is so much uncertainty there that a football field is far far too small an area to be thinking of.




The later. The lander has no means to do course-corrections on the way down. It's only propulsion is to 'stick' it to the surface during touchdown.

What I'm seeing in ESA's drawings is exactly that - landing ellipses. There is uncertainty in deployment velocity and gravity field ( which is being characterized as we speak )

The Huygens landing site was picked via engineering. The Philae site is being selected via a combination of engineering AND scientific goals and they will be targeting a specific location on the surface to aim for.

If you follow the links you'll get to the HiRISE team page for the observation
http://hirise.lpl.arizona.edu/ESP_037190_1765
Where it says
This image was targeted to cover part of a small “chaos” terrain, where there are lots of steep slopes.

Yup - there's threading -but only inside the collar mechanism that pulls dust up into the CHIMRA mechanism

http://www.nasa.gov/images/content/727102m...-43_946-710.jpg
http://bestdrillingbits.com/wp-content/upl...bit_diagram.jpg

Infact - the drill doesn't really spin round like a drill at all. It's more a percussive chisel that rotates only at about 60rpm...not the hundreds and hundreds of a typical 'drill'

https://www.youtube.com/watch?v=nq9xUr4T7E8

Why would wheel wear have an impact on rover longevity?

Senior management would disagree


http://www.nasa.gov/mission_pages/mer/news/mer20100126.html

Brownish motion is the result of impacts upon a particle by the molecules of the fluid it's suspended in (i.e. dust floating in an an atmosphere or in suspension in a liquid of some sort)

How does that apply here?

That's exactly what it does - and that's what I do to start down the road of making HDR images myself. By under-exposing, for example, you get more detail out of a bright window. By over exposing, you get more detail in the shadows. Stack'em'all up and magic occurs

There is some merit to doing it with the 12 bit imagery from the PDS - but it's going to be pretty limited with the 8 bit JPG's that are already clipping top and bottom.

But - tone mapping - the adaptive brightness/contrast control applied to a single image - that's one way to get 'more detail' out of a single image.

There are two HDR techniques. One is simply exposure fusion - compressing multiple exposures to capture detail in both highlight and shadow regions of photographs.

The other is tone mapping- this, at some given radius, adjusts the brightness/contrast/gamma etc of the image area by area such that everywhere can express more detail (i.e. brighten areas in shadow to see detail there, darken areas like skies to see detail in clouds)

I dabble in landscape photography and I'm pretty fond of what the latter, done with a little subtlety, can do.

http://dougellison.smugmug.com/Landscapes/...int/i-3hKxSfc/A

Not questioning the results - just wondering what your pipeline is that requires making faked +/-ev pictures first.

Why bother going thru that process? Just load the single image into, say, Photomatix and work with it there. You're just tone-mapping an 8-bit image - there's nothing to be gained from trying to fake different exposures.

Are these not contradictory statements?

No - the centripetal acceleration is 4 orders of magnitude less than the escape velocity.

It's where the bulk of activity appears to be
http://sci.esa.int/rosetta/54471-comet-act...-2-august-2014/

If it were rotating fast enough to displace the two halves if the 'neck' were to disappear....then it would also be rotating fast enough to rip itself to shreds.

What I have in essence done is prove that the comet can exist (which is somewhat self evident)

Rotation rate is 12.7 hours. The circumference drawn by the 4km length of the comet ( a 2km radius ) is 12.6 km

So very roughly - it's doing 1km/hr or 0.28m/sec. V^2/r is thus 0.000039 m/sec^2

Surface gravity is approximated as 10^-3 m/sec^2 3 orders of magnitude higher than the centripetal acceleration due to rotation.

Thus no - they would not fly apart. They would collapse together.

Nope - just un-textured STL's for printing.



I'll look into it - but it would be pretty low res so might not be worth the effort.