Thursday, January 29, 2015

Radar and NEO

Here’s something that I found interesting. I get a daily update known as the Astronomy Picture of the Day. Today’s (January 29) was about the close approach of the Near Earth Object (NEO) known as 2004 BL86, which is about a third of a mile in size and if it struck the Earth could cause widespread damage and loss of life. It came within three quarters of a million miles of Earth or about three times the distance between the Earth and the Moon.

Now all that is interesting and I often joke about worrying about the asteroid that is going to strike the Earth. It really isn’t much of a joking matter because of the destructive potential of such a strike, especially if it hit a population center.

But all that isn’t the real point here. What caught my attention in the description of the close encounter (yes, I used that term on purpose), they wrote, “Still, the close approach to planet Earth allowed detailed radar imaging from NASA’s Deep Space Network antenna at Goldstone, California and revealed the asteroid to have its own moon.”

The largest ships ever build on Earth are just under a third of a mile long. I mention that for some perspective. Now we’re told that not only can these Earth-base radars detect something relatively small at such great distances, but it is capable of discriminating between an object some 1700 feet in diameter and its much smaller companion.

I think you all can see where I’m going with this. If we have a radar system that good, with that ability, what else might it have detected closer to Earth? Does that system operate all the time and what is it searching for? Oh, I know, it probably is set to look for these small asteroids in their near Earth orbits, but they must see other things at other times such as satellites, space debris and the like. What do they do with those objects that don’t fit into the normal astronomical  or other categories? Are those data collected or just ignored? Are they sent to another organization such as, oh, I don’t know, the Air Force Space Command?

These sorts of things would be classified, of course. National security. We wouldn’t want our competitors in the world to know just how good these radar systems are so the information from them would be classified and besides, we don’t have a need to know.

This might be a path that we wish to follow. Who knows what a FOIA request might shake loose… or we might just learn that they have nothing that is responsible to our request… or call it a goose egg.


albert said...

They do say the radar resolution is 13ft/pixel, which would make that 230ft moon ~17 pixels long. Pretty darn good at 740k miles!
According to NASA, the Hubble can see objects ~210ft long (at 248k miles), so around 210ft/pixel.
So the radar has much higher resolution than Hubble. What am I missing here?
I can see that NASA might not want to give out any information which might affect national security (and I fully agree).
I gotta go...

Bob Koford said...

Many years ago I was compiling info for, what was hopefully going to be a book. The hard drive that I was using was hacked, and the entire system was destroyed. I was able to save only a handful of documents, and text from it. My first blog: UFOB: Of VITAL Importance, was also hacked.

The three main subjects I was researching at the time were: the now famous LD McLaughlin documents, documents dealing with the Airman Bunce case at Wright Patterson (also dealing with Aztec), and the National Security Space Architect (NSSA) and their handling of the Residence Space Object catalogues.

RSOs covered all the objects being tracked...from Near Earth Objects, to every nut and bolt their cameras could resolve.

When I was looking into this, the RSO catalogue contained an UNIDENTIFIED category. I remember it numbering in the hundreds.

I had also found thst Project BLUE BOOK had a catalogue of the UFOs in the CORONA BROCHURES...which appeared to be the equivalent of the RSO catalogues UNIDENTIFIED section.

Bob Koford said...
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cda said...

"These sorts of things would be classified, of course. National security....and besides, we don’t have a need to know."

We certainly DO have a need to know if an NEO was about to collide with the earth!

Hence if this super-duper radar facility detected a large UFO near the earth I think we can take as certain that the authorities would inform the public. The same would apply even if the said object was determined to be an asteroid or other natural object.

Come to think of it, if this radar facility really is classified (or top secret), how come you know about it, and are able to tell the world?

KRandle said...


The site is not classified. It's existence is not classified. Some of the products would be classified... and while the tracking of an NEO would not be classified, the track of a potential enemy's satellite would be classified... or the close apporach of something that is not natural and not manufactured on Earth.

cda said...

I accept that the track of a potential enemy's missile or satellite would be classified.

I do not accept that the track of a manufactured object from beyond our planet would be classified. The reason being that there is no provision, within the official rules & regulations (of the US or any other country) for unearthly manufactured objects of any kind, since no such things are known to science.

Unless you know otherwise, of course.

Larry said...

In my day job, I work on the Planetary Defense problem, so I know a little bit about this.

The radar tracking of NEOs in the US is done exclusively from 1 or 2 facilities. The primary one is the Arecibo radio dish in Puerto Rico. As I have discussed before, radar has the characteristic that a signal is transmitted from an antenna to a target, the signal bounces off the target and some of the signal returns to the transmitting antenna. The outbound signal strength diminishes with distance, squared, and the return signal also diminishes with distance, squared, so the combination falls off with distance to the fourth power. As a practical matter, that means that to detect objects with radar at large distances, you need a lot of peak power in the outbound signal. The Arecibo dish has one transmitter with 20 TW peak power.

Also, the resolving power of any kind of telescope scales like the aperture diameter, divided by the wavelength of light that the telescope operates at. The aperture of the Arecibo dish is about 305 meters. That compares to 2.4 meter aperture diameter for Hubble Space Telescope. However, the wavelength of the radar signals that Arecibo transmits are about 4 to 5 orders of magnitude longer than the visible light that Hubble uses. So, the intrinsic resolving power of Arecibo is thousands of times worse than Hubble. To make up for that, they sometimes operate Arecibo in an interferometer mode wherein they transmit signals from Arecibo using the high power transmitter and receive the signals at one of the 70 meter dishes at Goldstone, California in the Mojave Desert (part of NASA's Deep Space Network). The distance from Arecibo to Goldstone becomes the effective aperture diameter, which increases the resolving power to as good as or better than an optical telescope. If the press release was quoting 13ft/pixel, I would guess that they must have used the Arecibo-Goldstone baseline.

As to the possibility of using something like the Arecibo-Goldstone setup to detect UFOs: The Arecibo observatory is set up to track objects in the sky that are moving at the angular rates at which planets move--approximately 15 degrees per hour. The tracking is accomplished by that little cable car suspended over the face of the Arecibo dish, and there's only so fast you can make it go. Any presumed UFOs in cis-lunar space would presumably not be moving at exactly the speed necessary to track them, and so would appear as highly transitory blips flashing through the field of view. As I understand it, Arecibo already detects signals like this when aircraft or spacecraft accidentally fly through the beam. They simply reject such signals as noise.

albert said...

Thanks for the info...It's nice to know that we have such clever folks working on this stuff.... or is it?......

Robert Sheaffer said...

I doubt very much that radio telescopes like these would ever turn up an unknown object, even if one were nearby. They don't simply look outward and see what they find. Instead, as Larry explained here, observing an object is a difficult and painstaking operation taking a lot of planning and coordination. You scan some exact point, and coordinate with another site, to get decent resolution. You don't simply stumble across things, and record them.

KRandle said...

All -

I get that they set the limits of discrimination that would probably exclude anything coming in at a slower rate. I get they're not looking for UFOs. I get the overall purpose of this... I just wonder if they get anything truly strange, what would they do? It seems we have the capability but I get that we probably aren't using it to look for flying saucers.

Bob Koford said...

I should have denoted that my point was: even though I don't know the answer to your specific question regarding deep space tracking, it is provable that the secret tracking/spy systems...such as CORONA, were indeed used to track and photograph UFOs, by combining with ground based radar. MITs Lincoln Labs is a main partner in this, with NSSO. As such, the U2 almost certainly was used as well, utilizing its side-view/Over The Horizon camera systems.

Before anyone accuses me of making it up, I can tell you this was discovered because of a major Air Defense study that was undertaken during, and because of the Vietnam conflict. It was called CORONA HARVEST. A very few of the documents that should have been purged from the BLUEBOOK files were missed. If one looks, they will see them. The author admitted he used files from BLUEBOOKs CORONA BROCHURES. Which would also seem to indicate that incidences such as the one mentioned by former Director Brown (the "enemy helicopter" statement)

Since the same NSSO evolved from these programs, who handle the RSO issue, which evolved from the Project Twinkle attempts, themselves, actually, I should think that if they had too, and they knew to look, they could locate just about anything they want.

But that is my assumption.

Bob Koford said...
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Larry said...

I should make it clear that my comments regarding the uselessness of the Arecibo radar for discovering UFOs do not necessarily extend to the other many modalities that would be available to the US government (or other militarily advanced governments, for that matter). Even though the Arecibo setup is referred to as radar (because it measures the time of flight of a RF pulse from the transmitter to the receiver) it is not set up to scan large volumes of space for the purpose of detection of objects. In the case of NEOs, the NEO is first detected using visible (or perhaps IR) wavelengths, its orbit is determined, and the Arecibo dish is pointed to the coordinates in space where the object will pass. It is capable of detecting NEOs only when they are at the point of closest approach to Earth and therefore largest in apparent size. For the other 90+% of their trajectories, they are too far away for the amount of signal strength Arecibo has.

However, there are several categories of powerful military radar systems that are set up to detect and track previously undetected objects moving through the atmosphere and near-Earth space such as the NORAD Space Fence, ballistic missile defense radars, etc. I am not an expert on those systems, but most radar systems these days that are intended for some primary purpose have software algorithms implemented in them to filter out radar returns that are not useful for the primary purpose. For example, for the Space Fence, you are interested in tracking objects in orbit; objects that are not moving at the orbital velocity corresponding to the altitude they are at, are rejected by the algorithm. Conversely, if you are interested in tracking incoming warheads, you want to pay attention only to those objects that are not in orbit. If you're tracking aircraft, your radar might be set to ignore objects apparently moving faster than some particular speed. So, the day to day operators of those radar systems do not necessarily see on their displays the returns from "anomalous" targets.

The same is true of our assets in space that look back toward the Earth. Some of our military satellite systems monitor the globe continuously in the thermal IR part of the spectrum. They can detect heat sources like missile launches and aircraft going into afterburner.

Basically, all these systems generate a data stream in service to some primary purpose, which is not to detect UFOs (as we would use the term). That data stream is usually filtered to discard signals that are not germane to that primary purpose, so operators of those systems do not necessarily see UFO signatures very often or perhaps at all.

However, the raw data streams could be filtered with different algorithms to display the signals that do look like UFOs (assuming you know what they're supposed to look like). It would require an agency with the appropriate clearance level and a clandestine budget to get access to the raw data stream. There's no reason it couldn't already be happening, as Bob Koford's comments would imply.

Bob Koford said...

Thanks Larry.

I would like to make one last point about what I commented on:

If someone were to inform me that the Corona Brochures did not deal with UFOs (as we would think of here)it would not diminish their importance in this matter, as they resided with Project: BLUEBOOK...the UFO program.

This is because it would absolutely verify, once and for all, that Air Defense Plan BLUEBOOK of 1952 (of which the plan actually was germinated in 1948, by, I believe Chidlaw)and the Project:BLUEBOOK that we are all familiar with, are indeed one-in-the-same.

Thanks again.

Bob Koford said...

For anyone who might stumble onto this post, and the comments, I thought I should mention that I have been gathering much information together, recently, on the UFO/CORONA connection.
There is quite a bit...a lot more evidence than you might be thinking.