Mercury Flyby 1 Options

[peter59]

'n1ckdrake' - I think Astro0 meant 25 to 30 Kilobytes per hour.

Correct Kilobytes.

25-30 Kilobytes per hour? Are you sure? Rather 25-30 Kilobytes per second.

[Bjorn Jonsson]

25-30 kilobits per second (kbps) seems likely. Downlink bandwidth is usually given as kbps and 25-30 kbps is comparable to various inner solar system spacecraft. It would be nice to know for sure the correct value though.

[ugordan]

Even 25 kbps sounds like a rather low bandwidth for inner solar system standards. Granted, MESSENGER doesn't use a dish antenna, but still - Cassini can get over 100 kbps from 9 AU away.

[Ant103]

What extraordinary times we're living

If you want, I have made a desktop version of the last pic Messenger send us.

Attached thumbnail(s)

 

[djellison]

Even 25 kbps sounds like a rather low bandwidth for inner solar system standards.

No - Messenger really is quite a low data rate mission. Cassini has a great big HGA. Messenger doesn't.

Doug

[ugordan]

I guess that's a Discovery class imposed weight limitation. It's expected that MESSENGER will, on average, get up to 80 full resolution images per day once in orbit. This is based on onboard compression speed and mission requirements (which I guess are greatly affected by available bandwidth).

It's remarkable how tight the point spread function of the wide angle camera is, it looks tighter than 1 pixel. In fact, it almost looks like it's causing some aliasing and the WAC images certainly don't need any sharpening applied like the NAC images do. WAC is a great context camera, one of the sharpest imagers I've seen; look at the sharpness of small craters near the terminator. Can't wait to see the color version of the above image.

[Guest_Oersted_*]

Marvellous images: what a great age to live in!

[dvandorn]

OK -- 30 kilobits per second, I can see. At 30 kilobytes per hour, you would be getting about 210 kilobytes over seven hours, and even the jpeg'ed images we've already seen are larger than that. Each.

Unless there is some kind of uber-compression going on here of which I'm not aware, I would think it would be hard to fit 1,200 images into a file only 210 KB large.

-the other Doug

[robspace54]

When I was a mere boy, Mariner 4 flew past Mars and sent it's fuzzy, smearing 22 photos of Mars back at the rate of 8 1/3 bits per second!!!! That makes 25 kilobits per hour sound high, but the effective bit rate is less than 7 bits per second... In this age of digital instant gratification waiting is not something we like to do.

I am really enjoying the "instant science" here. It reminds me of the Pioneer and Voyager flybys. :-)


Rob

[tedstryk]

Galileo made us forget how much the internet had advanced things, since it was often months before the data was on the ground.

[David]

Would anybody like to have some fun matching the new image to this old-style telescopic albedo map from the early 20th century?

[Phil Stooke]

Good luck! Unfortunately, Antoniadi and all astronomers of the time thought Mercury was tidally locked to the sun. That's why his map shows just one side. It's really a composite of all 360 degrees compressed into 180. Every time Antoniadi looked at Mercury and what he saw didn't look the way he imagined it should, he thought clouds were interfering with his view - clouds on Mercury, I mean. A dark spot was hidden by hazes, or a bright spot was a thick cloud.

So this map can't be used as you suggest. When the rotation became known (from radar studies) a new map was compiled and used to redistribute placenames around the planet for the IAU. Rotational effects do make our views selective, so there is some relationship between Antoniadi's map and the later IAU map. But your question really should be applied to the IAU map.

Incidentally, the original names of USGS map sheets are taken from the old albedo nomenclature. Caloris is in Liguria, if you need to know!

Phil

[SpaceListener]

A quick questions.

I doubt that Messenger will not take zoomed pictures like MRO? I am not able to get the value of image resolution (m/pixel) of narrow and wide angle imagers of Mercury Dual Imaging System.

I am interested if MDIS will be able to take an even more detailed pictures of landforms and surface features than the recently posted ones.

Is the Mercurian landform regolith alike to Moon since Solar energetic particles bombard its surface even stronger and more than on the Moon? This would lead that the Mercurian surface would very dusty like Moon or Mars?

[djellison]

This single image was picked to be downlinked as it was the highest resolution image image that included the whole planet. It's about 3km/pixel

Now - MDIS will not reach HiRISE resolutions. But the highest resolution images from this flyby will be about 120m/pixel - so about 25 times better than this first returned image.

http://messenger.jhuapl.edu/encounters/ind...&timestep=7

Doug

[JJR2]

That is indeed, and it's replacing my current wallpaper (an Apollo montage), it'll be interesting to see just how many people mistake this for the Moon (and believe me it will happen).

I don't know if I'm quite ready to replace my Spitzer IR montage of the center of our galaxy just yet.

So, will we have to wait until 2011 for the "good stuff"?