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Orbiter Successfully Enters Orbit
dylanduck writes "Mars Reconnaissance Orbiter has slipped safely into orbit - unlike two of the last four orbiters NASA sent to Mars. Remember Mars Climate Orbiter and the mix up between metric and English units? MRO is going to send back 34 trillion bytes of data, more than all the previous missions put together." From the article: "The spacecraft will use a suite of six instruments, including the most powerful camera ever sent to another planet. This will image objects as small as 1-metre wide and should be able to snap pictures of the Spirit and Opportunity rovers. The instruments will track the planet's weather, geology and mineralogy, and even probe about a kilometre beneath its surface to hunt for water."
NPR has an area on their website covering not only this orbiter but past probes as well.
http://www.npr.org/templates/story/story.php?stor
No we don't. We're in a transition period. To be clear people have to use "trillion bytes" or "tebibyte". "terabyte" is currently ambiguous.
Pounds, miles, hogsheads etc are not "English" units. Please call them by their correct name "Imperial Units". This is not a joke name, it is what I was taught to call them when I was a child.
I went to an English "Public School" and am now over 40. I only know my weight in kilogrammes. We went metric a long time ago!
I'll see your Constitution and raise you a Queen.
HiRISE, under the best of conditions, will do about 30 cm/pixel sampling, giving it a resolving power of just over half a meter. So it is indeed the most powerful camera in Mars Orbit.
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Well, the Mars Global Surveyor did take a picture of (albeit farther away) of Spirit's landing site-tracks, heat shield, and parachute. You can't see the actual rover. http://en.wikipedia.org/wiki/Image:Mgs_mer.gif
g s-images.html especially the Mars Odessey as seen by the Surveyor
This might be of interest to you. From the nasa website: "The Mars Orbiter Camera can resolve features on the surface of Mars as small as a few meters or yards across from Mars Global Surveyor's orbital altitude of 350 to 405 kilometers (217 to 252 miles). From a distance of 100 kilometers (62 miles), the camera would be able to resolve features substantially smaller than 1 meter or yard across" Take a look at the pictures on this site: http://www.nasa.gov/vision/universe/solarsystem/m
The Surveyor orbits at 235 miles above Mars.
Why do Americans like to call Imperial units "English units"? It's like they're trying to pass the buck or something. Come on guys, the English stopped using Imperial units a long time ago. Own up to your own antiquated ways and call them "American units". After all, you're the only ones in the world using them now anyway.
Are you sure the pics in that Pop. Sci. article were from orbit? Many very impressive "spy satellite" pictures out there actually came from U-2 spy planes. I don't think we had that kind of resolving power from orbit 25 years ago.
Still trying to think of a clever sig...
Also, be wary of stuff that has been "declassified." The spy satellites can do some pretty amazing stuff to be sure, however I am a little skeptical of this claim. I've got a little experience with some of the people that do this work, and to be sure they can do some incredible stuff, but reading 1 inch tall lettering on the ground from space would be quite a stretch even now, and likely impossible back in 1980.
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I'm entirely not convinced that was from a spy satellite (to read 1-inch high lettering, the targetting and stability problems alone would be quite difficult to solve for such high resolution; you'd have blurring (from spacecraft issues and the person holding the book), mis-targetting, etc.). Given that:
All of the electronics have to be radiation hardened. This usually puts back the technology by a few years to even a decade compared with what one could afford without the rad-hardening.
Given that, the actual resolution is 20-30 cm per pixel (depending on distance from the surface). That's 10 or so inches. However, you can't actually resolve/recognize anything that's only a pixel across. The canonical requirement is 3+ pixels to be sure you're detecting what you think you're detecting. So, the actual resolving power is about 1 meter.
If the spacecraft (and camera) had been designed to orbit at a lower elevation, the resolution would have been higher, but as it is, it's pretty darn close to Mars' atmosphere and you don't want to orbit there. MRO's orbit is going to be about 320 km above the surface. Some satellites at Earth (I have no idea if they're "spy" sats) orbit at around 150 km above the surface--much closer. Many spy planes fly over the surface at only a few tens of km. With that and some amazing engineering to reduce smear, they could easily resolve very small objects.
One of the major issues with HiRISE is going to be spacecraft jitter (the spacecraft shakes, other instruments move, etc.). This could effectively limit the resolution by a few factors if it's not resolved. There is a high stability mode in which nothing is allowed to move and the spacecraft holds itself still while HiRISE images very important targets (future landing sites, etc.), but that mode is resource intensive and excludes some instruments from doing certain activities. What HiRISE is trying to do is equivalent to trying to take a picture of the street through a glass-bottomed car at 125 about miles per hour.
Another problem is context--sometimes the MOC images are uninterpretable because we don't know what's going on around them. With too-high resolution images, we'll just be looking at... well, noise, essentially. We can't really understand things without context to place them into. That's why we have a MOC-equivalent "context" imager bore-sighted with HiRISE.
All-in-all, this is the most powerful telescope/camera sent to another planet.
http://news.bbc.co.uk/2/hi/science/nature/4542174. stm
OoO
Please do not publish outside of
>I'm entirely not convinced that was from a spy
>satellite (to read 1-inch high lettering, the
>targetting and stability problems alone would be
>quite difficult to solve for such high resolution;
>you'd have blurring (from spacecraft issues and
>the person holding the book), mis-targetting,
>etc.). Given that:
>
>All of the electronics have to be radiation
>hardened. This usually puts back the technology by
>a few years to even a decade compared with what
>one could afford without the rad-hardening.
I don't know why this keeps coming up. In applications like this, computing power *is not* and *has not* been a limiting factor on spacecraft performance. Period. "Faster computers" have provided nearly no improvements in performance in applications like this. In fact, if you are really serious about high-bandwidth control systems you are still better off with *analog* and the requisite technology for that has existed for 50 years with negligible improvements. In fact, most if not all of the sensors (like earth sensors, star trackers, and any variety of gyroscopes) still use analog at the lowest level.
If anything, the advent of "better computers" and "better computer languages/programming practices" have probably *set the industry back* in terms of performance, and certainly set it back in the area of productivity. OO programming is probably great for some applications, but a control system implementation is essentially a procedural task. I've been in the business long enough to see the switch from analog/logic matrix hybrids, to procedural (done in FORTRAN, JOVIAL, and assembly) to OO. Some of the most efficient, clearly written, and maintainable code I've seen was implmented *using only IF statements and gotos*. Yes, you CAN write spaghetti code with FORTRAN, etc, and you CAN write clear and straightforward procedural code with C++. I've seen some absolutely incredible examples of both. But, if nothing else, in the good old days, you couldn't use the sort of stuff that you see in OO programming, because your GET and SET functions alone would suck up the entire memory and/or CPU. All that "better computers" have allowed is massive bloat, and associated explosion of questionably-applied OO programming. For this application the desired level of abstraction is the *bit*. But I feel another rant coming on...
More computing power and digital flight control systems provide much more flexibility and more easily-implemented features - but they DO NOT necessarily have anything to do with improving pointing performance.
In any case, the limiting factor in getting high-resolution has absolutely nothing to do with rad-hard technology dragging down performance. Sufficient controls performance can be acheived without computers at all, and was possible and achieved in the 60's
Structural exitation (jitter, bending) IS a limiting factor on performance, and most of the items that need to point some device accurately are designed with this in mind. But it's always a tradeoff between rigidity/damping and weight.
In any case, the ultimate limiting factor on the resolution is the size of the objective (almost always a mirror), and there's only so much glass you can launch to Mars with a relatively inexpensive rocket. You want to double the resolution, come up with 10x the money, and I'm sure we can figure out a way to get it.
Brett
They already re-imaged it: Linky
Though, like you said, it doesn't matter: If you disagree with him, you're part of the conspiracy!
Actually, the radar instrument on Mars Express (MARSIS) and the radar instrument on MRO (SHARAD) are made by the same group from the Italian Space Agency. The MARSIS radar is capable of detecting features further below the surface than SHARAD, but as you mentioned SHARAD will have a greater amount of detail.
All in all this will be a fantastic mission -- it's been well thought out. For instance, HiRISE (the extremely high resolution camera, made by Ball Aerospace) is co-aligned on the spacecraft body with CTX (the context imager, built by Malin Space Science Systems), so that during the science phase they'll take a context image (which will cover a few miles squared) and then do high-res imaging of the same area with HiRISE.