Could we make a smaller spy satellite

I believe that we could have, if we don't already, have a smaller cheaper and better satellite. Using a laser and some common technology, I believe that it would be not only possible but practical to do so.

What I want to know is should we or should we have done?

One problem I forsee with making a smaller spy satellite is that a smaller vehicle would almost necessarily be less capable. The size of a telescope's mirror - and, let's face it, spy satellites are just another sort of space telescope, albeit one designed to look down at Earth rather than out at space - is directly related to the effective resolution of that telescope, paticularly for the visible part of the spectum.

Annecdotal reports of the latter KH-series spy satellites suggest that they're about the same size as the Hubble telescope; this evidence is based on the known capabilities of the launchers used to put the spy satellites in orbit (including the now-defunct Titan IV), by which we can approximate the weight of the satellites and compare them with the known weight (~24,000) of the Hubble. Reports also suggest the KH-11, -12, and -13 satellites were shipped in containers similar to the one Hubble was shipped in, which would mean that what we know about the Hubble is useful in considering the sizes of spy sats: Hubble is 43 feet long and 14 feet wide, or about the size of a Greyhound (bus, not dog).

Which is big, but not huge. Big means higher telescope resolution, which means more detailed data for our nation's spy agencies. I doubt that it would be practical, from a data-gathering standpoint, to significantly shrink the size of current spy satellites. Even if it were possible from that perspective, I don't know that the cost involved could be recouped in savings on launch vehicles (i.e. Delta IV medium instead of Delta IV heavy).

And, in any case, if you have a nigh-unlimited black budget to play with - why bother?

[edit on 2-11-2006 by PhloydPhan]

I was thinking a lot smaller than that. About the size of a beach ball or basket ball.
The optics could be of small size which is easier to manufacture with a high quality. The telescope optics do not have to be extremely accurate and we maybe able to not even use a reflector.

As for the resolution, that depends on the speed of the electronics used in the detector and the quality of the laser beam.

If your smart you all ready know the technology that I'm referring to. This is not the same thing as the Hubble. It could not replace the Hubble in function but I could make a very nice spy satellite.

And I'm saying that it isn't that simple. You said, and I quote:

The optics could be of small size which is easier to manufacture with a high quality. The telescope optics do not have to be extremely accurate and we maybe able to not even use a reflector.

I'm sorry, and don't mean to be rude, but the sentences above tell me that you don't know anything about optics. Telescope mirrors DO have to be manufactured to extremely high tolerances; poor manufacturing in Hubble's mirror led to absolutely terrible pictures like these, necessitating the December 1993 STS-61 mission. Mirror defects in spy sats would have similar effects - and good mirrors cost a lot of money.

And the mirrors need to be big, too. Compare sources at FAS, Jane's Defense, and Global Security and you'll get slightly differing data, but the consensus is this: KH-12 spy sats (or KH-11B, depending on your nomenclature of choice) - the newest in our inventory, apart from the slightly apocraphal KH-13 - are about 15 feet wide by 50 feet long, with a primary mirror that is anywhere from 2.3 meters to 4 meters in diameter (this would be very highly classified information and, thus, is a guess, differing from source to source). This allows it to see objects on the ground which are anywhere from 6-10 centimeters in size - the true resolution would also depend on the composition of the object (i.e., solid fences would be easier to see than the chain-link variety). Bear in mind that this is all from an eliptical orbit that ranges anywhere from 150-900 km above the Earth.

Resolution doesn't depend on "the speed of the electronics used in the detector", as you put it. Detailed pictures DO require large, high-quality mirrors, which require large support structure around them to provide propulsion (spy sats can change orbit, within certain constraints; KH-12's carry several thousand pounds of rocket fuel), power and batteries, communications equipment, etc. A beach ball won't cut it, I'm afraid.

As for use of lasers in spy satellites, the only use for a laser in a spy sat (at least that I can see) would be as an altimeter like the one in use aboard the Mars Global Surveyor. But, in a spy sat the size of a beach ball, where are you going to put batteries to power your laser, support for the solar panels to recharge the batteries, communications equipment to relay your intel to Earth, etc.?

And yes, I realize that you're not talking about re-building the Hubble, but the analogy is an accurate and instructive one. If you'd read some of the literature available on the subject, you'd know that.

Originally posted by PhloydPhan
One problem I forsee with making a smaller spy satellite is that a smaller vehicle would almost necessarily be less capable. The size of a telescope's mirror - and, let's face it, spy satellites are just another sort of space telescope, albeit one designed to look down at Earth rather than out at space - is directly related to the effective resolution of that telescope, paticularly for the visible part of the spectum.

why bother?

[edit on 2-11-2006 by PhloydPhan]

Welll....

You're making a couple of big assumptions there.

First, we're talking about Spy sats. You assume that all spy sats are optical satellites. Not true. Just as vital to strategic optiacal intelligence is signal intelligence. SIGINT uses what amounts to large orbital antennes: "Big Ears" in space.

Second, large diameter mirrors are only necessary if the object being observed is extremely faint in the visible spectrum. The large size of the mirror allows the telescope to gather the most availble light. Visual acuity, the sharpness of the captured image, has little to do with the size of the mirror and more to do with the mirror's precision.

Advances in electronics and optics (and electro-optics) have made much greater capabilities availible in much smaller packages. Adaptive optics, advanced CCD's, and flight control software that allows an armada of small vehicles to "flock" and cover a wider area than any single large sat could ever hope to cover, mean that there are now significant advantages to "thinking small".

Your getting warmer. Modern batteries can last for aweek or more if your only using 20-100 mW. Throw out the CCD, we don't need one. We don't need corrective optics either.
A laser can be used for more than just an altimeter. I bet that you see one used for this type of purpose about every day, if not several times a day. I also bet that you have never heard about one on a satellite.


Correction: I mean throw out the CCD array. We're not taking a picture we're doing a ...

[edit on 4-11-2006 by angryScientist]

Thanks, Bhadhidar - I was focusing on optical surveillance satellites because that's what I'm most familiar with. I agree that the advances in adaptive optics and electro-optics are interesting - and that my mind didn't even go there before your post! - but I still feel that the net impact on mirror size of these technologies is going to be minimal. Large mirrors will still be needed to collect and focus reflected light from dim light sources - camouflaged weapons emplacements, vehicles, etc. I would bet that advances in optics are going to make our already impressive orbital surveillance capabilities even better, but I don't see them eliminating the need for relatively sizeable spy sats.

As for SIGINT sats, they too use (as you noted) LARGE orbital antennas, and radar surveillance sats like the LACROSSE series are sizeable as well. You're right to say that a small armada of these sats can replicate the capabilities of a single, larger unit, but then you run into problems like the ones mentioned above: where do you keep maneuvering fuel on a micro-sat, where do you keep the batteries, communications equipment, and - unique to this "flocking" application - how do you keep the entire flock flying in precise formation, considering the slighly different rates of orbital decay, etc? All problems we can solve, certainly, but I think they will combine to keep spy sats pretty goodly sized for the foreseeable future - i.e. the size of compact cars, at the smallest.

As for you, angryScientist, care to actually contribute to the discussion you started, rather than toss in a few lines like: "If your (sic) smart you all ready know the technology that I'm referring to."? How about some links, or at least spelling out what you think lasers and the like could be used for on a spy sat, since you seem to be an expert on the subject?

Here is the idea.
You have all seen a barcode scanner. A little dot of light sweeps over the barcode label. A small electronic eye is all that's needed to pick the variations in light intensity. Laser scanners are used for high end digital image capture.

I would have thought that this technology would have been exploited to the max, but it hasn't and I can't figure out why.

You could also use the beam as a projector if you modulate the intensity.




[edit on 6-11-2006 by angryScientist]

Originally posted by angryScientist
Here is the idea.
You have all seen a barcode scanner. A little dot of light sweeps over the barcode label. A small electronic eye is all that's needed to pick the variations in light intensity. Laser scanners are used for high end digital image capture.

I would have thought that this technology would have been exploited to the max, but it hasn't and I can't figure out why.

You could also use the beam as a projector if you modulate the intensity.




[edit on 6-11-2006 by angryScientist]

Bar code scanners are purely digital image readers. laser in question simply allows the reader to distinguish between black or white , which in the digital world reads as either on, off; a one (1) or a zero (0). Product information is encoded in the bar code in such a way as to allow the scanner to "read" and decipher the info.

Useful surveillance images are far more complex than the bar code images that have caught your imagination. At least 90% of a sat image's info is in the gray-scale between the black and white a simple bar code.

Ever see that old optical illusion where you're shown a picture that looks like nothing more than a bunch of black splotches on a white page...until the image moves and it turns out to be a black and white cow in a snow covered landscape?

That high-contrast still image is what the laser-based system would see.

For effective intelligence you need high-resolution, not high-contrast.

Another problem is that laser light tends to scatter as it passes through the atmosphere. Bouncing an orbiting laser off an object on the ground to image it would compound the optical scatter of the illuminating beam: the laser would be scattered by the atmosphere from orbit to the object, scattered by the object itself, and scattered even further by the atmosphere as it returns to the spysat to be imaged.

[edit on 6-11-2006 by Bhadhidar]

Here is something.

"laser linescan system"

From Department of Defense
Definition: (DOD, NATO) An active airborne imagery recording system which uses a laser as the primary source of illumination to scan the ground beneath the flight path, adding successive across-track lines to the record as the vehicle advances.

See also infrared linescan system.

Also;

A laser line scan image of the Phantom II ROV. The laser line scan captures so much detail, that the printed words on the ROV (on the right hand edge, underneath the tube) can almost be read.

oceanexplorer.noaa.gov...


Here is something more.
Laser camera