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It appears that six European satellites have gone missing from the NORAD tracking catalog. All are in highly elliptical orbit and, historically, were “tracked” once each orbit, which in the case of the four Cluster II satellites (used to keep track of solar weather) about once every 2.4 days. The last updates to their orbital elements were made in mid-November. What could have happened?

Actually, losing satellites used to be not too uncommon, even important adversarial satellites. I did a study once that looked at Russia’s (and, of course, the Soviet Union’s) early warning satellites. Those were observed, on average, about once every day. But they would occasionally be lost. Usually this was associated with, for instance, the Russians moving a geostationary satellite to a new longitude. Sometime between one observation and the next planned one, the Russians had moved the satellite to a slightly different altitude and it had “drifted” at a rate of over 1 degree per day to a new position. Usually, the US tracking network picked the satellite up before it reached its new position and it could be watched moving along the geostationary band.

The incidence of losing satellites greatly decreased when the US started using a satellite-based telescope to track satellites. Called the Space-based Visible (SBV) and mounted on the MSX satellite, this sensor tracked satellites for ten years. Unfortunately, it stopped functioning in June of last year. We can look back on the history of observations of the Cluster II satellites and see the effect of the death of this sensor on the frequency of observations of the Cluster satellites. During all of 2007, there where 14 times when observations of the Cluster II FM8 were made on every other orbit. In the 5 months between SBV’s demise and when the Cluster II satellites were lost, there were a total of 11 times the satellite was tracked less frequently than once every orbit and several times when seven or more days passed between observations. It would be interesting to know if ESA moved these satellites in November but we certainly can see the importance space-based observations have played in space situational awareness.

Comment [2]

The International Herald Tribune reported yesterday that Islamabad and New Delhi has exchanged the list of their respective nuclear installations and facilities on New Year’s Day, in accordance with the 1988 Agreement between India & Pakistan on Prohibition of Attack Against Nuclear Installations and Facilities.

According to the agreement, the term ‘nuclear installations and facilities’ includes:

…nuclear power and research reactors, fuel fabrication, uranium enrichment, isotopes separation and reprocessing facilities as well as any other installations with fresh or irradiated nuclear fuel and materials in any form and establishments storing significant quantities of radioactive materials.

Both countries have classified the list, but I learned the approximate numbers today. India has declared 30 facilities while Pakistan has declared “about 20”. The Indian government has put some university sites on the list, presumably because “significant quantities of radioactive materials” are stored there. I cannot give you more specifics than that.

It is, however, encouraging that the list continues to be exchanged despite the heightened tension between the two countries. One day, perhaps, the list will be made public. But don’t hold your breath.

Comment [1]

Urs Tinner, alleged Khan middleman, is free — according to AP:

A Swiss man suspected of involvement in the world’s biggest nuclear smuggling ring has been released from prison after more than four years of investigative detention, his family said Sunday.

Urs Tinner, 43, was freed several days ago, his mother, Hedwig Tinner, said by telephone from eastern Switzerland.

His brother Marco Tinner, 40, remains in detention while prosecutors appeal his release to the federal criminal court in Bellinzona, she said, declining to comment further.

Pretrial detention is no picnic, but it is shocking to me that not a single one of the alleged Khan middleman has done a day in prison after a conviction — with the possible exception of Gotthard Lerch. That one I am still not sure about.

Comment [3]

Click on the image for more detail.

$15 from shirt.woot. F’ing awesome.

Comment [1]

I remember having a conversation with a missile engineer some time ago about the North Korean Nodong missile; he said “no one in their right mind would field a missile that has only been successfully tested once!” At the time, that made a lot of sense to me. But exactly how many tests do you need? And more importantly, how do you decide how many tests you need? These questions should all be determined by the reason why tests are performed in the first place.

I think I understand bullet testing. When developing a new bullet, you test it millions and millions of times to make sure they work right in all imaginable situations and that you have a high degree of confidence that they will work. But, of course, bullets only cost a dollar or two each so there is little problem with running a standard quality control test program to allow you to achieve real confidence they are going to work. National missile defense tests cost about $100 million each so we are never going have the “95% confidence that the system works 95% of the time” that some critics of missile defense have been advocating. (I’m not against that in principle; I’m just saying it’s never going to happen. Any missile defense development program has to be adjusted to that reality.)

I was reminded of my conversation with the missile engineer when NASA announced it was awarding SpaceX part of a $3.5 Billion dollar contract to deliver supplies to the ISS based on a single successful test flight. SpaceX is quickly becoming my favorite sociological experiment in missile development. Touted as a more cost effective way of getting into space, SpaceX has hired former NASA engineers and uses government facilities without, I’m sure, contributing to paying off their development costs; just some sort of use fee. But now, it seems, that the real way they are going to save money is not to have the sort of expensive testing program we might expect from a government development program. This isn’t going to be a rant against SpaceX, which as I say, is one of my favorite sociological experiments (which also doesn’t imply that I think they are doing the right things!) The problem is, I’m not sure what the government would use that development program for, anyways. If we are not using flight tests to determine statistical reliability, perhaps only one successful test is really all that is needed. If so, what does that tell us about countries just starting the development of their missiles?

Tests Associated with Various Development Programs

Program	No. of Tests	No. Successful Tests
Falcon-1 (SpaceX)	4	1
W-76	4	2*
RS-24	3	3
Al Samoud I (Iraq)	37	33
Al Samoud II (Iraq)	24	22
Nodong (DPRK only)	2	1
Taepo’dong I (DPRK)	1	0**
Taepo’dong II (DPRK)	1	0

*I have arbitrarily dropped the two tests with anomalous results from the successful column. **First 2 stages successful.

Integration Tests

One reason I like the Falcon-1 test series so much is illustrated by the reason the third flight test failed. Developed by engineers and scientists who have had plenty of experience developing other missiles, this missile failed (I believe) because they were concentrating so much on economic factors, namely the reuse of the first stage engine. If you want to reuse an engine, you don’t want to go firing pyrotechnics that blow holes in the nozzle to quickly drain the fuel. On the other hand, if you don’t quickly and reliably shut the engine down, the remaining fuel might cause the first stage to continue to produce a little bit of thrust and hence risk bumping into the second stage engine and breaking it as they separate. That is exactly what happened. Could SpaceX have caught this error if it had run more ground checks? If so, were they cut to reduce design costs? I hope you see why I like it so much.

The RS-24 is another interesting case that seems to be devoted to testing an integrated system. Pavel Podvig has made a very convincing argument that the RS-24 is a Topol-M missile with more than one warhead uploaded onto its bus. In that case, perhaps it shouldn’t need very many flight tests to get it up to speed. In fact, one might think that only the post-boost bus needs testing. But perhaps even that doesn’t need much testing since some claim that the Topol-M’s bus was tested for more than one warhead without loading any more on it by simply maneuvering as if it did have the warheads. (Some Russians claim exactly the same thing for some US post-boost buses. The US responds to those charges by claiming that additional maneuvers were needed for range safety reasons. And so it goes.) On the other hand, as the Falcon-1 test series shows, integrating different components does introduce new modes of failure. Were three tests enough? Apparently so, since Russia has said they will now introduce the RS-24 into their arsenal.

Statistical Uncertainty

The US philosophy of testing nuclear weapons is perhaps the hardest to understand; not least because so much is buried in secrecy. One could have imagined that, since the US performed over 1054 nuclear explosion tests (it appears that some tests had more than one explosive device tested at a time) and “developed” a total of 112 nuclear weapons, they could have used these tests to establish a reasonable statistical reliability for each weapon. After all, this corresponds to nine tests per bomb design with a significant number left over for testing one-point-safety, which would be reassuring. Except that the US testing philosophy was never to test to this level.

Instead, our nuclear tests were supposed to develop weapon designers’ expertise; an expertise from which they could judge the reliability of a nuclear design without further testing. This must rely on two assumptions that are probably true most of the time: 1) that the non-nuclear components are tested individually and as a whole enough times to establish a statistical reliability for the non-nuclear functioning of the design and 2) the nuclear process involves so many “particles” that statistical fluctuations cannot have a significant effect on the design’s function.

Some doubt that the later is true for the W-76, a mainstay of the submarine leg of our nuclear triad. Critics have suggested that the possibility that a macroscopic instability exists that violates the second assumption. It is also one of the few warheads for which the US has released information on its testing. It had a total of four tests during its development and apparently two of them had “anomalies.” They could have had anomalously high yields, or anomalously low yields, or anomalies that didn’t affect the yield; the open literature doesn’t say. However, we know that one anomaly resulted in a retest and the other in a change in a component (but no retest). Fortunately, there have probably been enough tests of the W-76 with the few stockpile surveillance tests done in the later years of testing to establish a reasonable statistical reliability, especially when more than one warhead is devoted to each target.

Other Countries
Given these examples of developed countries’ R&D programs, Iraq’s development of the Al Samoud I and II are very reassuring. Not only did they use flight tests to iron out the bugs, they went on to what we would call an extensive operational test and evaluation series. The last 11 Al Samoud II flight tests were for verification of the “firing table,” determining the range under various conditions such as changes to the pitch program etc. (One of these failed, so the operation failure rate of the Al Samoud II was probably around 10%.) Still, I cannot help suspecting that somebody in a powerful position might have made a lot of money for each test flight flown. Hence their large numbers. Still, if other countries followed this sort of a testing program, we would never miss their development of an ICBM.

North Korea, on the other hand, doesn’t seem to need nearly as many flight tests. Apparently only one successful test was needed for DPRK to start selling its Nodong missile abroad. Various analysts have come up with ingenious reasons for this and they could very well be right. But, on the other hand, do we really understand why and how we test complex systems well enough to claim to understand North Korea’s? I am full of doubt.

Note added: Just to be clear, when I say I think there have probably been enough stockpile surveillance tests of the W-76 to give a reasonable statistical confidence to the W-76’s reliability, that was not the intention of the surveillance tests. In fact, this statement is based only on my estimates of the numbers tested that I derived from a correlation analysis and published in Jane’s Intelligence Review in July 2005. As I hope I made clear, the reliability of nuclear weapons is officially based on the judgment of the designers and not on tests. Perhaps not surprisingly, that is probably the case with all the other tests considered here.

Comment [4]

Frank Pabian sends along a response to the comments on his presentation.

Regarding the comments posted so far regarding my Youtube briefing, first, I would first like to thank all the commenters for their questions and comments on the various aspects of the presentation.

However, I must also say that I’m surprised and sorry to learn the following:

1. That I’ve been labeled a Hawk, and,
2. That due to a small error on my part in verbally describing slide #90, that I would have provided anyone the basis for determining that the credibility of the entire briefing is therefore in doubt. (This is most unfortunate given that the presentation lasted one hour and incorporates over 110+ slides).

Although I have never thought of myself as hawk (given that I consider violence of any kind, either at the individual or national level, to be abhorrent; and given that I have not, and will not, ever advocate unprovoked military action by anyone at any time) perhaps a metaphorical ornithological review is in order. A hawk (or an eagle?) has the ability to see far off and focus in on what is important, in this case the developments that suggest a growing threat of nuclear weapons proliferation. If one chooses to ignore or dismiss such information, I don’t think that he or she should be considered a dove, but rather an ostrich (or a pigeon?).

Regarding the US Executive Oder #13224 labeling the NCRI as a terrorist group…It was made in December 2002. However, that in no way inhibited the IAEA from following up on NCRI leads long after that (and there should be no doubt that the IAEA achieved much success as a result). So, as Josh later said, it is a non sequitur as to whether NCRI information has any value or not, or whether or not it is worthy of follow-up by anyone concerned with international security.

(The proof is in the pudding, regardless of who made it)

Regarding Rwendland’s other comment that takes issue with my slide #90 showing the various examples of Magnox reactors. I would like to respond by saying that the slide #90 was correct as originally created and as viewed standing alone, as it was only meant to provide examples of how knowledgeable bloggers (i.e, on ArmsControlWonk) were correct in drawing attention to known Magnox reactors as a basis for comparison with Al Kibar long BEFORE the ODNI audiovisual presentation in April 2008. I did nonetheless mis-speak in saying that that central image was a cutaway model of a Calder Hall reactor when it was in fact (as Rwendland accurately points out) a view of the much larger, but still Magnox, reactor at Oldbury (and I’m actually not aware of such views being available with respect to the Calder Hall reactors). As a result, and in order to avoid any similar confusion in the future, I have now updated that slide as enclosed. Rwendland is also correct to point out that the heat exchangers in the Oldbury design are internal as opposed to external at both Calder Hall and Yongbyon (and al-Kibar)… this can be seen on either side of the core in the Oldbury cut-away model. Rwendland is also correct to point out that the Oldbury reactors employ a pre-stressed concrete pressure vessel as opposed to steel containment vessel used at Calder Hall (and evidently at Yongbyon, and as was shown by the ODNI in the ground photos of Al Kibar).

I’ve included two additional slides that show both reactor types as they now appear on Google Earth. However, please note that the four cooling towers (one for each of four Calder Hall reactors) visible in the Google Earth image, have since been demolished by controlled demolition (akin to the one at Yongbyon) and the reactors decommissioned as of last year.

Both of the Oldbury Magnox power reactors were similarly slated for decommissioning this year, but that was recently postponed as the Oldbury #2 reactor will continue to provide electricity through at least 2009.

These slides also provide refutation to [the] questioning the authenticity of the ground image of a Calder Hall reactor in Slide #90. A quick comparison with the overhead view on Google Earth shows that it was indeed a ground view of Calder Hall (Reactor #2).

Again, thanks to all who have commented (and have yet to comment), as I see this is the beauty and true value of Blogs and Wikis…They provide a forum in which to correct, clarify, and elucidate on myriad topics in a way not otherwise possible, with the end result being that everyone is better informed.

Cheers,
Frank

Comment [13]

Jeffrey writes in his recent post about BX-1 being a Rorschach test and he appears to be right on so many levels. I thought I’d riff off of his excellent post and focus in on one aspect that has been bothering me for quite a while: defining what maneuvering actually means. You see, space isn’t so big or empty as many of us think it is and that has a lot of implications. Certainly I thought it was much bigger and emptier than it really is until I made this plot:

This plot shows how often a cataloged object comes within a given distance of a hypothetical equatorial satellite at an altitude of 855 km. The dotted line shows how this would increase purely with cross sectional area (R^2).

It turns out that satellites pass fairly close to something fairly often and often that something is a functioning satellite. Now this plot is for a hypothetical satellite with a circular orbit at an altitude of 855 km, very close to the most popular orbital altitude. (Its also the altitude of the FY-1C China shot down in January 2007, which is why I made this plot.) But it shows that such a satellite passes within 45 km of a cataloged object about once every half hour. Several of these each day are functioning satellites so if we are concerned about passing close to the ISS, perhaps one “rule of the road” should be that some orbital altitude bands should be reserved for human activity. That seems to me to be the only way of reducing this sort of fly-by. On the other hand, China’s BX-1 was released as part of a manned mission so perhaps even that incident wouldn’t have been regulated.

If, on the other hand, we are concerned about countries developing their ASAT capabilities by testing ASAT components on other satellites (such as trackers or guidance systems) we cannot simply say: don’t come within such and such a distance! That’s simply not practical since satellites come within very close distances of something quite often. Instead, we need to add something to make a practical rule. I proposed a ban on actual maneuvering near another object, say within 100 km; something that happens every 5 minutes at 855 km altitude. By that, I meant actually accelerating away from the initial Keplerian orbit. Of course, even that would be difficult to time even by a country that was intent on obeying the rules so perhaps you need to introduce yet another requirement, say, an object greater than such-and-such apparent magnitude or size. As you can see, things quickly get very complicated because space is neither as big or as empty as we like to think.

Comment [2]

You can see an animation of the BX-1 companion satellite at 1:57 into the clip.

Anybody remember that really boring paper I wrote, in 2004, calling for “rules of the road” regarding autonomous proximity operations? (That’s when satellites maneuver around one another.) Me neither, but according to the internet, I said:

The launch of a Chinese micro-satellite with the capability of SNAP-1, let alone the XSS-11 or DART, would generate concern in many quarters of the United States. If the Chinese were to conduct a proximity maneuver near a U.S. satellite, the reaction would be apoplectic.

So, four years later the Chinese put up a small micro-satellite, BX-1, on a recent Shenzhou launch. It maneuvered near the ISS (sort of). Cue the apoplexy:

Richard Fisher, senior fellow at the Washington DC-based International Assessment and Strategy Center, and the author of a new book, China’s Military Modernization, Building for Regional and Global Reach, is not surprised that there has been no official US statement or response to this puzzling episode.

“We do not know how close the BX-1 actually approached the ISS. But for me, at closure speeds of 3.1km/second, the Shenzhou-7 was already too close at 45 kilometers. I expect that in time leaks or questions from the Congress will lead to revelations of more data about the BX-1 pass-by of the ISS,” says Fisher.

This is precisely why we need rules. As it turns out, the Chinese were operating safely. But with few or no rules, what seems safe to a Chinese aerospace engineer may be way too close for Rick Fisher’s comfort. Without any rules defining legitimate behavior in space, BX-1 is an inkblot.

What you see says more about your personality than the Chinese space program. Peter Brown sums it up nicely:

BX-1 could well be little more than a peaceful probe merely engaged in “close proximity” operations with cameras and transmission equipment aboard. Or it could be a prototype satellite attack dog, a space surveillance and Space Situational Awareness (SSA) platform with anti-satellite (ASAT) capabilities, all rolled into a single menacing platform ready to pounce.

If you are the sort of person who likes to make decisions based on information, here is my recommended reading list on the BX-1 and proximity operations in general:

— Michael Katz-Hyman, Proximity Operations in Space, The Case for a Code of Conduct, INESAP Bulletin 26, June 2006.

— Jeffrey Lewis, Autonomous Proximity Operations: A Coming Collision in Orbit?, March 2004.

— Brian Weeden, China’s BX-1 microsatellite: a litmus test for space weaponization, The Space Review, October 20, 2008. (I think Brian mean inkblot, since litmus is an objective indicator of whether a solution is acidic or alkaline.)

— David Wright and Gregory Kulacki, Chinese Shenzhou 7 ‘Companion Satellite’, Union of Concerned Scientists, October 21, 2008.

Comment [11]

Sorry for the light blogging of late. I got a chuckle out of this story:

US firms now control UK’s nuclear weapons plant

LONDON (AP) — Britain’s government said Friday that a state-owned nuclear group has sold its stake in the company that manages the U.K.‘s atomic weapons research center, bringing the facility under the control of U.S. companies.

British Nuclear Fuels PLC has sold a one-third share in Britain’s AWE Management Ltd. to Jacobs Engineering Group Inc, based in Pasadena, California. AWE Management has a contract to operate the government-owned Atomic Weapons Establishment, which has facilities in Aldermaston and Burghfield in southern England, through 2025.

The sale means that operations at the center, which makes and maintains warheads for Britain’s nuclear missiles, is now under the control of U.S. companies.

I think it comes as a shock to most people on either side of the Atlantic when they learn how much the UK depends on the United States for its nuclear deterrent. Even I was a little taken aback during my visit to Aldermaston when Don Cook, the Managing Director of the Atomic Weapons Establishment, began to address us in his flat American accent.

I thought “Whiskey Tango Foxtrot? Couldn’t they have found someone British?”

After a couple of days at the AWE, and a tour of the lovely historical collection, I accepted the reality that, no, the United Kingdom does not in any way, shape, or form have an independent nuclear deterrent.

I mean no disrespect to all the people at Aldemaston who endure the nightmarish hell of living in and around Basingstoke to keep their country safe from … well, anyway. And I understand the need for the polite fiction given political debates in the United Kingdom, but the UK suffers when US policymakers buy into London’s public relations strategy.

The fact that stunned me was the model, in the historical collection, of Red Snow — the UK’s first deployed thermonuclear weapon. (Forget Green Grass)

Red Snow is an “Anglicized” version of the US Mk-28. (Anglicized is the nice way of saying “copied”.) The first thing you observe about the the bomb is that compact little thermonuclear device is packaged into a GINORMOUS bomb casing.

The mockup at AWE is a cut-away, but this image from the Nuclear Weapons Archive gives you the idea.

The problem, we were told in the historical talk, was the UK was unable to manufacture the Mk28 to the original specifications.

One implication was that the bomb was too large for the US casing and had to be placed in reused Yellow Sun bomb casings. Another was that the designers had little confidence in the warhead without nuclear testing — which was a problem since the warhead was deployed during the 1958-1961 test moratorium. (I suspect it was eventually tested )

I was able to track down the first story, but not the second — until I noticed that AWE posted it on their website!

The British decided to produce a megaton yield American warhead design under the code-name ‘Red Snow’. The equivalent British device needed more development and more nuclear tests – not possible because of an agreed pause in testing by the three nuclear powers.

However, certain aspects of the American design did not meet the British Ordnance Board Requirements. Modifications were embodied and trials carried out in Australia. The warhead would no longer fit the original American bomb casing and a much larger and heavier British one had to be used.

Well, that’s honesty for you. (In their defense, I think they used a different high explosive.)

The UK has executed three designs since Red Snow — Anglicized variants of the B61, the W59 and the W76.

British Nuclear Weapons

British Desig.	Delivery	US Desig.	In service
Red Snow	Yellow Sun Mk.2, Blue Steel	Mk28	1961-1966
WE.177A-C	Gravity Bomb	B61	1966-1998
RE.179	Polaris SLBM	W59	1968-1982
ET.317	Polaris SLBM (Chevaline)	W59	1982-1996
Unknown	Trident SLBM	W76	1994-present

Author estimates. I could be wrong.

Presumably AWE does not make FOGBANK, SEA BREEZE or other speciality materials in the W76 — which basically means that UK decision-making about life extension for the Trident warhead depends entirely on the W76-1 Life Extension Program and/or whether the US builds WR1.

They must have been crapping Scotch Eggs when we thought we might not be able to make FOGBANK.

Comment [9]

click on the image for a larger version

The currently active US early warning satellites, SBIRS and DSP: each satellite is removed one at a time to highlight its individual coverage. Orbits have been determined by the amateur satellite observer network, see-sat, with particular thanks to Mike McCants, Greg Roberts, Peter Wakelin, and Scott Campbell

Now a ‘days everyone seems to know that you need at least two DSP or SBIRS satellites to track a missile in stereo. (Actually, that’s not exactly true. If only the US and Russia had continued with their RAMOS project, we could have jointly developed the sensors necessary to determine the 3D position of a missile with only a single satellite. That, however, is a different blog altogether.) But that is far from the only reason why we need at least two satellites observing every point on the Earth’s surface. Perhaps an even more important reason for having multiple observations of a missile’s heat signature is to eliminate false alarms.

Most, but not all, of the background from reflected sunlight is eliminated by looking at the Earth in only a very narrow band tuned to the wavelengths absorbed by water. Yesterday, we considered in detail the image taken by SBIRS HEO 2. One of the features of that photograph was a thunderhead that in all likelihood extended high into the atmosphere, past where most of its reflected light would have been absorbed by the surrounding water vapor. Today, we are going to look at a different source of background, sunlight reflected off of low altitude clouds but with a geometry where the sun, clouds, and satellite nearly line up. This results in what is known as specular reflection as opposed to the more common diffuse reflection. The later reflects much less light into the sensor and is, therefore, easier to eliminate as background.

The SBIRS HEO-1 checkout photograph (taken on 14 November 2006 of the launch of the DMSP F17 satellite from the Vandenberg AFB) provides a good example of how bright low altitude clouds can get:

click on the image for a larger version

The Delta IV rocket lifted off from Vandenberg on a generally southern heading (I estimate an azimuth of about 190 degrees, based on the 98 degree inclination of the orbit) which, in the image as presented above, makes it appear to go downward. There is a clear decrease in the track’s luminosity just below the upper part of the track (which is its start) that is a combination of the trough region, as discussed in my post on signal and background, and the 28 second gap between main engine cut off (MECO) and the ignition of the second stage.

The thing I want to discuss about this photograph, however, is the bright background near the top of the image. Again, this background has been “artificially” increased by combining the images taken over several hundred seconds while the signal has been smeared across a number of different pixels as the rocket moves across the scene. However, the clouds near the Earth’s limb are considerably brighter than the clouds appeared in the image taken on 11 June 2008 of the Delta II even though that image was taken at local noon. Here, the sun, Earth, and satellite have almost exactly lined up, producing the enhancement associated with specular reflection. If this had not been over the United States, and if the satellite had been searching for launches as opposed to waiting for an expected launch, it is possible other meteorological—in combination with the alignment—could have produced a false alarm and perhaps triggered a nuclear war. One possibility might be for a storm front to be moving obliquely across limb of the Earth and different thunderheads to be illuminated in turn. Of course, we are talking about a system that continuously watches the Earth for years at a time and is bound to see all sorts of different and unexpected phenomena.

That is exactly what almost happened in 1983 when specular reflection caused many people in Russia’s strategic forces to think the US had launched an attack of half a dozen or so missiles. Fortunately, Col Petrov, the officer in charge of monitoring the newly launched system, decided such a small attack could not possibly be used to start a nuclear war. He was court-martialed for his troubles but at least we didn’t all die.

It is an interesting question just how much this danger is reduced by the SBIRS very high revisit rates; I would guess that an image is taken at least once a second and added into these composites we see here. After all, with more points on the “trajectory” it becomes more difficult for a natural phenomena to fake a missile launch. However, it is best not to rely on that too much. Instead, the US can usually view the same launch from two or more satellites; in this case SBIRS HEO 1, DSP F14 and DSP F17 with a possible contribution from DSP F16 if it used its above-the-earth-limb sensor; a special sensor that is meant to view rocket launches at the edge of the Earth and which appear silhouetted against the black background of space. This is apparently the only why Russia views missile launches but they can still get into trouble from reflections off of clouds and hence maintain early warning satellites in both geostationary and Molynia orbits looking at the central US missile fields from two very different directions. There are still worries, however, that Russia is not maintaining a complete Molynia constellation of early warning satellites and, some fear, could accidently start a nuclear war triggered by some rare weather phenomena or other benign event.

If the US currently has enough early warning satellites for this overlap, some analysts fear that it might not in a few years as DSP ages. But that is another blog.

Comment [1]