August 29, 2007, HiRISE release Options

[Pavel]

Just messing about...

Waiting for Soup Dragon?

[kenny]

And the Polar Pit Gullies are fascinating.

Polar Pit Gullies


Especially the enlarged sub-image...

Polar Pit Gullies - enlargement

Looks like Scottish hillside gullies, with apparent "sheep tracks" crossing obliquely between the gullies...

Kenny

[Guest_AlexBlackwell_*]

Interesting new image of the Arsia Mons pit.

Perfect timing. And wouldn't you know it? I understand that the Cushing et al. paper ("THEMIS observes possible cave skylights on Mars") should be published online tomorrow in Geophysical Research Letters.

[tty]

Looks like Scottish hillside gullies, with apparent "sheep tracks" crossing obliquely between the gullies...

Kenny

Though these are thoat tracks of course.

[kenny]

Hej tty,

I think you mean "goat" ?

Do you have mountain goats in Sweden? I didn't see any when I climbed Kebnekaise.

[elakdawalla]

No, he definitely means thoat.

--Emily

[dvandorn]

Yep -- as someone else here once said, I would absolutely adore to see images from a Barsoom Reconnaisance Orbiter. BRO could resolve the great spires of the city of Helium, after all...

-the other Doug

[kenny]

Ah! Thanks Emily. I've obviously not been reading enough science fiction...

Kenny

[edstrick]

If we are VERY lucky, we may see the spires of the towers of Helium, thoats, green martians, and Deja Thoris in a few years. Pixar has the rights now and is apparently SERIOUSLY planning "John Carter of Mars".

For those that don't know, A Princess of Mars is the first, precedent setting and archtype creating "Planetary Romance", one of the two roots of modern Space Opera.

Quote:
A Princess of Mars is an Edgar Rice Burroughs science fiction novel, the first of his famous Barsoom series. It is also Burroughs' first novel, predating any of his famous Tarzan novels. He wrote it between July and September 28, 1911, going through four working titles. finished story was first published under the last of these titles in All-Story as a six-part serial in the issues for February-July 1912. The finished story was first published under the last of these titles in All-Story as a six-part serial in the issues for February-July 1912.


from http://en.wikipedia.org/wiki/A_Princess_of_Mars

[hendric]

Anyways, I was just wondering about MRO resolution, and the maximum possible. I know there were rumblings before the arrival that MRO's additional resolution wouldn't help any due to the limiting factor of Mars' atmosphere. Now that we're there and all, are there any new idea on the reasonable resolution limit from orbit? If we had a 5/2/1cm per pixel capability, when would we start getting dimishing returns?

[tuvas]

Well, it all depends on how big of a camera you want to send there. I think HiRISE is mostly diffraction-limited, and it's mirror is 50cm, I think. If you want to double the resolution, you have to double the size of the mirror, or get closer to the surface. I don't think NASA would like the latter option very much, so you're stuck with a larger mirror.

HiRISE's max resolution is near 20-30cm, although I think there's some pixel-blurring at the highest resolution (I haven't studied the optical system, and I'm no optical engineer anyways, but this is from my memory). Anyways, assuming you would want a 5cm resolution, you'd need to send a 2m mirror! I can't see that happening for a long while yet, HiRISE resolution is good enough for 99% of the things we could think of, I rarely have seen anyone asking for much higher. I could see another HiRISE being sent before they send another higher-resolution (As I understand, there's another HiRISE camera that's half-built on the ground, it's not out of the realm to send another one there, just thought you'd like to know that.) Anyways, just thought I'd through in my $.02

[monitorlizard]

A study document for the 2013 Mars Science Orbiter (available at the MEPAG website) weighed the advantages/disadvantages of sending a camera with 10 to 15 cm resolution. To eliminate pixel smear, they considered moving the CCD array during image acquisition, rather than moving the entire camera or entire spacecraft.
Ultimately, they decided that the weight of such a camera would be excessive and a HiRISE-class camera would be sufficient, given how little of Mars will be imaged by HiRISE itself during its lifetime. BTW, a HiRISE camera is not guaranteed for 2013, and will be competing for payload inclusion against things like an imaging SAR and advanced atmospheric instruments.

A resolution of at least 10 cm should be technically achievable from Mars orbit. Unclassified sources estimate that U.S. reconnaissance satellites get at least 10 cm resolution, and the Earth's atmosphere should be more of a challenge to compensate for than Mars'. Except during planet-wide dust storms, of course.

[ElkGroveDan]

Unclassified sources estimate that U.S. reconnaissance satellites get at least 10 cm resolution,

Actually they acquired images better than that. There are anecdotes from the latter cold war years of espionage agencies being able to identify individual license plates on vehicles. The letters on my California plates (assuming they are typical) are about 6 cm tall. Clearly you'd need resolution on the order of 2cm or finer to read them

[dvandorn]

I've always heard that those were just that -- anecdotes. However, from what I've heard, the more recent orbital reconaissance assets are multi-spectral, able to return images in color and in non-visible frequencies.

I've heard that the rumors of being able to read license plates were apocryphal, but that you could, in many cases, determine the issuing state of a given license plate from its unique color combination. You could also determine the rank of a given officer by the color of his shoulderboards (depending on the particular uniform specifications of the government you're observing).

Infrared imaging, of course, has very obvious benefits.

-the other Doug

[lyford]

Perhaps I am missing something obvious, but with license plates being mounted vertically on fenders, I never understood how they could be read from above... even if you are right next to the car.