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Landsat 7 Satellite Might Be Dead
Lord Satri writes "Landsat 7 ETM+ remote sensing satellite,
probably the most important Earth Observation satellite, might be dead now.
This would have very important repercussions on the remote sensing / space community."
The images must not look too bad, since it took them over a week to notice the problem.
'SBEMAIL!' is better than a goat!!
I clearly disagree.
:-)
ALI is costly.
ASTER has a very limited coverage.
Landsat 5's quality is far behind Landsat 7 ETM.
A lot of L7 data is free (thanks to UMD). Coverage is worldwide. And L7 is definitly the most used RS/OE data type. That's why I claim consequences are not anodine.
Animoog.org
You have obviously never seen Landsat data before. It is of little or no military value. There is no conspiracy here. Satellites break. Get over it.
Actually, I worked on several image processing projects for the military, and we certainly did use LandSat data. And SPOT data (optical band) and SAR data (K band and X band mostly) as well as IR data.
The advantage of LandSat data is the broad spectrum of data returned, not the resolution. As a consequence, LandSat data alone has little tactical use, but it has tremendous strategic value -- particularly when geolocated and registered with data in other bands, and in conjunction with other data. In one project I did for the Comprehensive Test Ban Treaty Verification Organisation in Geneva, the challenge was to develop criteria for distinguishing mining sites from non-mining sites using satellite imagery. What does this have to do with A-tests? you may wonder. An underground explosion could be part of a mining or roadworks operation, or it could be a nuke test.
You've got the location of the explosion easily enough from the seismics, and it's easy enough to distinguish from an earthquake by its distinctive P/S wave ratio (explosions have almost no shear wave component, it's all compressional). Now how can you tell if its an ongoing mining operation without actually visiting the site? First you geolocate and register your LandSat, SAR, AVHRR and SPOT data to each other in the region of interest. Throw in some vector road maps and topography while you're at it. Imagery from different days, months, years, decades in the same area is also quite useful. Now you can either sit down an analyst in front of the data, or you can develop algorithms for identifying mining sites from various combinations of imagery. When you're done, let me know. LandSat data is tuned for collecting land-use information. Tree cover, grasslands vs. exposed rock for example. Clearings in the jungle that weren't there before. Desert areas that suddenly change to vast warehouse complexes well away from the largest roads and typical commerical trucking routes. Get the picture?
It is of tremendous strategic value to unobtrusively monitor land use over time, over large areas, for all sorts of military applications. Other data are better for tactical applications in a silly little game of soldiers, true--but you're not going to even want that level of resolution and targeting for determining new developments. The world is a big place. Where do you look first, and what kinds of anomalies do you look for? What anomalies are potentially of strategic significance? Quick, give the answer without LandSat data. Not as easy now, is it?
And as for calling it a "conspiracy theory" -- it's rather well known that there exist American satellites that have been said to have malfunctioned that have certainly not, because the data being returned was found to have military, strategic or other significance. The LandSat 7 "malfunction" could well be another instance. No conspiracy there. Satellites go black for different reasons. Malfunction is just one of them.
Look at it this way. I leave five dollars on my desk and it disappears. The thief is caught on camera and given a warning. A week later I leave five dollars on my desk again, and, again it disappears -- but this time the thief is not caught on camera. Is it "a conspiracy theory" to say, well, this guy was caught stealing once, and he was in the area at the time, so of course we're going to question him. Does calling this reasonable suspicion based on past behaviour a "conspiracy theory" wash? No. It's just simple inductive logic. Get over it.
This is the perfect conspiracy theory: it's almost entirely plausible, almost impossible to refute, and we want to believe it!
Reasonable suspicion based on past known behaviour does not a "conspiracy theory" make. Every time a remote sensing satellite goes black, it's worth wondering of what tactical or strategic value was the data. And to do this well, you need to know what image processing and multisensor fusion algorithms are currently being used, by both your own nation, and your nation's enemies, as well as what other data they have available. It's not just the raw data, bucko.
On the other hand, I can get a pretty good aerial view of Downtown Baghdad any time I want it.
Yes, but what about Bankok and all of Brazil? What about March 2000 vs June 2003, i.e. What is your coverage like over time? Ever wonder what's going on just out of range of a single image? What went on the month before or the day after? What the area looked like in a mulispectral, SAR or IR images? What if your multisensor fusion algorithm is ten times more accurate when you add low-res multispectral to your high-res optical? What if it becomes ten times more useful when you have three images to compare over time, in the same area, versus just one? What if your algorithm has far greater strategic value if part of the data are believed by your opponent to be simply unavailable due to ostensible satellite malfunction? What if half of your own functioning satellites were taken down in a war? Wouldn't you be glad to be still getting the data from the ostensibly malfunctioning ones?
These are actual questions pondered in actual meetings. I have been presented with them in a technical setting, in the development of actual image processing applications. It's hardly a "conspiracy theory" to say that these questions are asked.
20-20 tunnel vision is of no use when there's a truck full of explosives coming at you from left field. You need your peripheral vision for that. And it's the missile coming right at you that's the hardest to measure the velocity of. So the more points of view you have, and the more measurements over time you can make, the better off you are, from a defense standpoint. As an American Citizen, I happen to like my country being well-defended, so I don't think it's necessarily a bad thing if LandSat 7 went black for some reason other than a straight malfunction. But it does make me wonder.