The tumbling behaviour of the mysterious Kosmos 2553 satellite

Framestack (530 frames) showing variable brightness of Kosmos 2553. Click image to enlarge

Over three years ago, on 5 February 2022, Russia launched a mysterious military satellite, Kosmos 2553 (2022-011A), into an unusual orbit at approximately 1995 km altitude, the outermost margin of Low Earth Orbit. Very few satellites orbit there.

Early 2024, US Congressman Michael R. Turner, chairman of the House Intelligence Committee, wrote an unprecedented public letter to House members in which said he had concerns about a "serious national security threath", urging then President Biden to declassify the information. Subsequently, various US news sources quoted various of the proverbial "anonymous sources", with often conflicting information about the nature of the threath, but all indicating some kind of Russian space weapon. And moreover: a nuclear weapon, alledgedly. See my earlier 2024 blogpost here. Based on statements that a kind of prototype of the satellite in question was in Low Earth Orbit 'in a region not used by any other spacecraft', Kosmos 2553 was identified as the likely suspect.

More recently, in April 2025, various news sources (e.g. here and here) reported that as of late 2024, Kosmos 2553 had started to tumble, indicating a possible loss of attitude control.

I imaged Kosmos 2553 on May 20, 2025, and it indeed shows a brightness variation that was not present when I imaged it a year earlier. The image above is a 530-frame (21.2 second) stack, and the brightness variation can be clearly seen in it. Below is a sequence of the actual video footage:

 

We can compare this to video footage from a year earlier (20 May 2024) when the object was steady:

 

I extracted almost 9 minutes of photometric information from the 20 May 2025 video. This shows a prominent flash cycle of (peak-to-peak) 2.22 seconds, with a regular pattern consisting of a brighter flash followed by a fainter flash, ad infinitum. 

Below is a diagram of the full 9-minute photometry series, and a detail of a part of the curve which shows the pattern of the brightness variation: the red line is a fitted multi-sinusoid who's main period is 2.22 seconds. Gaps in the data are moments the camera was repositioned, or the object was closely passing a star.

Click diagram to enlarge

 

 

Click diagram to enlarge

The datapoints in the diagrams are 5-frame running averages. The data in the two diagrams above have been corrected for range and phase angle variation, i.e. to absolute magnitude (normalisation to 1000 km range and 90 degree phase angle). 

The apparent observed magnitude varied between magnitude +5.7 and +9.4. Below are these apparent photometric measurements uncorrected for phase angle and range (note that a calibration of the data to the Visual band has been done to correct for instrument spectral sensitivity):

 

Click diagram to enlarge

The imagery was made from my home in Leiden, the Netherlands, with a WATEC 902H2 Supreme camera and Samyang 1.4/85 mm lens, filming at 25 frames/second. 

The photometry clearly supports reports that Kosmos 2553 has started a tumble or spin. Whether this means it is no longer operational, is another question that is less easily answered. Given the regularity of the flash period, the flashing could be due to spin stabilization. On the other hand: why did this only become apparent some 2 years into the mission?

In orbital data for Kosmos 2553, a sudden subtle change in orbital altitude can be seen starting around 15-16 November 2024 (see diagram below). Perhaps this is when the tumbling or spin started.

Click diagram to enlarge

Multiple analysts, including myself, believe Kosmos 2553 to be a (Radar) imaging satellite (possibly 'Neitron'). It has a ground track that after four days closely repeats itself, which would fit an imaging satellite. It is not clear why some in US Government circles believe that Kosmos 2553 is connected to a 'nuclear space weapon' program (presumably Ekipazh). That suspicion must be based on undisclosed HUMINT.

Russia itself has stated that Kosmos 2553 is a "technological spacecraft […] equipped with newly developed onboard instruments and systems for testing them under the influence of radiation and heavy charged particles". That explanation does not sit entirely well with several analysts: yes, at 2000 km altitude the radiation regime is different and more severe compared to a more typical Low Earth Orbit: but not thát much different and severe, really.

Nukes in Space?

ionospheric glow caused by Starfish Prime, a 1962 nuclear detonation in Space (image: Wikimedia)

It sounds a bit like the fictituous Goldeneye satellite from the 1995 Bond movie of that same name: a secret Russian weapon in space waiting to unleash doom.

The past few days the media have been abuzz about a purported Russian Space Weapon, either nuclear or not, either deployed or not. 

The initial source was US Congressman Michael R. Turner, chairman of the House Intelligence Committee, who in an unprecedented public letter to House members said he had concerns about a "serious national security threath", urging President Biden to declassify the information. Subsequently, various US news sources quoted various of the proverbial "anonymous sources", with often conflicting information about the nature of the threath, but all indicating some kind of Russian space weapon.

What kind of weapon exactly, is unclear, although it seems to be an Anti-Satellite weapon of some sorts (see below). What caught the attention is that the 'anonymous sources' seemed to indicate something nuclear: either a nuclear weapon in space, or a nuclear powered satellite. Whether this is correct or not or just paranoia, is unclear at the moment.

A spokesman of the US White House National Security Council, ret. Admiral John Kirby, in reply briefed the press but with little pertinent extra information, apart from stating that he could confirm that "it is related to an anti-satellite capability that Russia is developing":

 

He also made it clear that it is "not an active capability that has been deployed". In other words, there is currently not a weapon already lurking in space. And, he did clarify that it does not concern something targetting objects on the Earth surface.

It should also be noted that Kirby did not unambiguously mention (see below for what I exactly mean with that) that the 'capability' in question is nuclear, so this remains an unverifiable rumour from anonymous sources that might or might not be wrong. 

However, at 26:45 into the press conference, he does confirm that this Russian capacity is 'space-based': i.e. not a kinetic interceptor fired from earth, but a weapon to be deployed on-orbit; and he states, interestingly enough, that it "would be a violation of the Outer Space Treaty". 

The latter is an interesting phrasing and could perhaps be taken to indicate something nuclear after all (but: see what is following), as the 1967 OST, to which Russia is a signatory State, in article IV of the Treaty prohibits the deployment of Weapons of Mass Destruction (and very specifically nuclear weapons) in space. 

On the other hand, the remark of  "violating the OST" might simply refer to Article VII, that holds parties to the OST responsible for any damage they inflict in space on satellites from other Nations; or Article IX that says that signatory States should avoid "harmfull contamination" of Space (such as the creation of harmfull space debris from an ASAT test). 

So it all remains ambiguous here and the 'capability' in question might not have any nuclear aspects (e.g. being nuclear-powered, which is not a violation of the OST, or a nuclear weapon, which is) at all, depending on how you interpret the wording of Kirby's statements. There is a lot of interpretational wiggle room here.

That Russia is pursuing anti-satellite (ASAT) capabilities is nothing new. In November 2021, they conducted a much-criticized kinetic ASAT test targeting and destroying their Kosmos 1408 satellite (see my earlier posts here and more elaborate here) that created orbital debris in Low Earth Orbit and made astronauts and kosmonauts onboard the ISS briefly take shelter in their Soyuz capsule. 

The new element of the capability that is now the subject of all this discussion, appears to be that it is to be space-based. But even that is not really new. Over the past years, there has been much concern about Russian proximity operations in space (Russian satellites approaching other satellites, either Russian or from other countries, very closely: or ejecting sub-satellites/apparent projectiles).

In 1987, the former Soviet Union attempted to launch a prototype space-based laser weapon,  Polyus/Skif (that launch failed). Maybe they are up to something like that again. And for a long time, it is said that Russia is working on a nuclear-powered electronic warfare satellite, Ekipazh.

proximity operation of the Russian LUCH/OLYMP 2 SIGINT satellite close to a commercial geostationary satellite, as seen in this image I made from Leiden on 20 Sept 2023

 

In general, ASAT weapons are usually not weapons that are smart to use, as they do more harm than good.

Both kinetic ASAT weapons (that destroy satellites and in that process generate a lot of potentially harmful orbital debris) and nuclear detonations in space for use as ASAT, are indisciminate weapons that do not only harm your target, but potentially also harm other satellites, including your own satellites and those of Nations not part of the conflict in question. 

This is not the case for every ASAT weapon though. For example, a weapon that would attach to a target satellite and mechanically or electronically sabotage it, would be less harmfull to other satellites, although it does produce at least one piece of space debris, a dead satellite.

[clarification added 17:30 UTC on 16 Feb 2024:
The paragraphs below discuss a nuclear EMP device in space. There is however another option, that of a nuclear powered but in itself not nuclear ASAT weapon, where a nuclear reactor provides the power source for another type of weapon, e.g. a very powerful laser (see the mention of Polyus above) or radio jammer (see the mention of Ekipazh above). This was one of the SDI concepts back in the 1980'ies. Nuclear powered satellites in itself are not new: both the Soviet Union and the USA have used them in the past, for example the Soviet RORSAT's that used nuclear power to power a powerful radar. Nuclear powered satellites do not violate the OST.]

As the nuclear spectre was raised by the 'anonymous sources' (which could have political agendas to do so), let's discuss this for a moment. Before the OST came into effect, Nuclear weapons tests have actually been conducted in space. And the results were very concerning.

The most well known of these is the US Starfish Prime test of 1962, part of Operation Fishbowl, where a 1.4 megaton nuclear bomb launched by a Thor rocket was detonated in Space at 400 km altitude. But there were also three smaller, earlier, low yield US tests in 1958 as part of Operation Argus.

Starfish Prime surpassed all expectations, leading to a halt in this kind of testing. Detonated at 400 km altitude over Johnston atoll, the Electro-Magnetic Pulse (EMP) created by the nuclear detonation actually inflicted damage at ground level on Hawaii, 1450 km away, where it knocked out some streetlights and parts of the telephony network.

(Note that in our modern world, where lots of electronics work based on microprocessors which are very vulnerable to EMP, we are much more vulnerable to such effects than the world was in 1962).

1962 Starfish Prime detonation flash as seen from Honolulu (image; Wikimedia)

 

 

ionospheric glow caused by charged particles from the 1962 Starfish Prime detonation (image: Wikimedia)

 

In addition, charged particles generated by the detonation and carried along the Earth's magnetic field damaged several satellites. 

Of the 25 satellites in earth orbit on that date (this was the early space age), nine were damaged and eventually failed early as a result of this test. It concerned seven US satellites, one UK satellite, and one Russian satellite.

The damage is done by beta particles and electrons generated by the detonation, which spread through the earths magnetic field and ionosphere (which includes a considerable part of Low Earth Orbit), and damage electronic components in satellites. Some of these particles can linger on in the ionosphere for quite a long time (months).

In addition, the charged particles released into the ionosphere by the test generated Aurora-like effects on low latitudes, generating conditions that speed up the orbital decay of satellites.

In other words: using a nuclear bomb as an ASAT weapon in space, is not a very sensible approach. I would be surprised if Russia would use such a weapon, as its side-effects potentially could criple its own space assets too.

[note added 18 Feb 2024:] And it might actually do less harm to western military satellites (the ones Russia would want to target) than to civilian satellites, as several critical military space platforms have actually been hardened against EMP.

update 18 Feb 2024: CNN has published a story that is getting some traction, where it appears to be claimed that the 'weapon' in question is in fact an EMP device. 

But it is again based on anonymous sources: and anonymous sources so far have been contradictory in this, and there could be political agendas behind such 'anonymous' statements. Only a few years ago, a group of hawks in US politics were trying to push the alarmistic story that North Korea was developing (and even would already have tested, a claim which is certainly bogus) space-based EMP weapons (a dark interpretation of North Korea's KMS satellites). Their agenda was that they were advocating for a preemptive strike on North Korea.

(note: added a few sentences on the 1980'ies Soviet space-based laser weapon Polyus/Skif and the Ekipazh concept a few hours after the initial version of this post appeared).

North Korea's Hwasong-17 ICBM: capable of (briefly) bringing warheads into orbit?

image: KCNA/RodongSinmun

According to multiple western sources and North Korea, North Korea conducted a first full-power test-flight of its new Hwasong-17 ICBM on March 24, 2022, at 5:34 UT, from Sunan close to Pyongyang.

The Hwasong-17 is the Behemoth missile that was first revealed to the outside world one-and-a-half-years-ago during the 2020 October 10 parade in Pyongyang and surprised everyone by its massive size at the time. It is North-Korea's largest, heaviest missile so far and visually looks like a Hwasong-15 on steroids.

[NOTE: some sources are now casting some doubt on the missile identity, suggesting that footage from the failed March 16 launch (see below) was used. See comment at end of post]

The test launch was confirmed by North Korean State sources which produced a written account on their KCNA and Rodong Sinmun websites, accompanied by photographs, while KCNA also broadcast a video of the test. The imagery underlines how impressive the size of the Hwasong-17 is: it is a Monster of a missile!

 

image KCNA/Rodong Sinmun

 

image KCNA/Rodong Sinmun

 

image KCNA/Rodong Sinmun

The video report on the test as broadcast by the North Korean State Agency KCNA is spectacular, with a glamour role for the sunglasses-clad North Korean leader Kim Jung Un (look at 3:55 to 4:05 in the video below!). It evokes shades of a Hollywood action movie trailer. 

(the actual footage of the test and test preparations starts at 3:25 in the video, after the usual bombastic introductions by news anchor Ri Chun-hee)

Earlier test flights of components of the same missile might have taken place in Februari and early March (but not on full power), according to western sources. North Korea claimed at the time that it was testing components for a reconnaisance satellite program. 

We also know that on March 16, another test flight from the same launch-site (near Sunan Airport), possibly also a Hwasong-17, failed shortly after launch at an altitude of less than 20 km.

But the March 24 test flight appears to have been successfull, as claimed by both North Korea and western sources. According to North Korean official State sources it reached an apogee at a whopping 6248.5 km altitude, with a ground range of 1090 km and a flight time of long duration (1h 7m 30s).

Western sources that independently tracked the launch mention similar ballpark values for this test: apogee "6200 km" and range "1080 km" according to the S-Korea Joint Chiefs of Staff; apogee "6000 km" and range "1100 km" according to the Japanese Government. The missile came down in front of the Japanese coast inside Japan's EEZ, at some 180 km from Cape Tappi. 

The apogee is at an extreme altitude, and this test was hence extremely lofted, as can be seen in this trajectory reconstruction I made:

click to enlarge

Looking into the necessary impulse in order to assess maximum range of the missile, I realized that the resulting nominal impulse of 7.85 km/s I reconstruct, actually means that the Hwasong-17 can achieve orbital speed. In other words: this means it is powerfull enough to, in principle, loft a payload to (low) earth orbit and get it (briefly) orbital!

Objects can complete at least one revolution around the earth if they have enough orbital velocity such that they can orbit at at least 100 km altitude (the exact value of the lower limit of orbital flight is debated: for circular orbits it might be possible at altitudes as low as 80-90 km, but it anyway strongly hinges on the drag characteristics of the object in question). The corresponding orbital speed at 100 km altitude is 7.84 km/s (for a circular orbit). The nominal impulse I get for the March 24 launch, at 7.85 km/s, matches that (in reality, it is more complex, as the missile will experience atmospheric drag during the initial phase of launch, which was not part of my reconstruction. And part of the initial impulse will be lost due to gravity pull before reaching 100 km altitude).

So in theory, this missile could briefly get an object (e.g. a warhead) in orbit around the earth, rather than on a suborbital ballistic trajectory. In case you wonder: it didn't on March 24, because it was not launched on an orbit insertion trajectory, but rather straight up.

 

image: KCNA/RodongSinmun

image: KCNA/Rodong Sinmun

image: KCNA/Rodong Sinmun

 

This was not something I had expected. But it gives a new meaning to North Korean claims from earlier this year that tests conducted then, possibly with Hwasong-17 components, where in connection to a space launch program.

They did fairly and squarely present the latest March 24 test as an ICBM  test flight though.

The launch location at 39.188 N, 125.667 E (as geolocated from the imagery by Joseph Dempsey) was on a concrete strip about 1.75 km from the main buildings of Pyongyang Sunan airport. That concrete strip is part of the Si-Li Ballistic Missile Support Facility which itself is some 2.5 km southwest of the airport:

click map to enlarge

click map to enlarge

But let's get back to the realization that this missile can apparently reach orbital speeds. This means that it - or components of it - in theory can be used for road mobile satellite launches. But it can also mean that you can briefly bring a warhead in orbit, either for a full revolution or more, or - cough - for a "fractional" orbit....

Remember the discussion of the Chinese test of a FOBS ('Fractional Orbital Bombardment System') in July last year?! See this earlier post.

I have been doing some modelling. Based on specs of an early '60-era US warhead, the W56, I modelled whether a launch of a similar warhead into a very low 100 x 105 km, 98.0 degree inclined polar orbit from Sunan, could reach the USA. 

I used the General Mission Analysis Tool for this, with the MISE90 model atmosphere and F10.7 solar flux set at 100. I modelled for a 275 kg warhead with assumed Cd 1.0 and a drag surface of ~0.15 m² (comments on how realistic those values are, are welcome) and under the assumption that the launch vehicle does achive sufficient orbital speed to insert it in such a 100 x 105 km orbit. The modelled launch was in southern direction, taking the long but undefended southern Polar route over Antarctica, approaching the USA from the south after finishing just over half an orbital revolution. [info added later: The model is strictly for the warhead assuming release from the missile upon orbit insertion: I did not model prolonged coasting as part of a post-boost vehicle of any kind].

With the mentioned specifications, I model it to nominally come down fairly and squarely in Ohio (or any other place within the continental USA if you adjust the orbital plane launched into somewhat), as the map below in which I have plotted the modelled trajectory for the warhead shows....

click map to enlarge

 

So: is the development of this missile perhaps a prelude to the development of a North Korean FOBS? With a suitable warhead, it appears they could do it with this missile.

Incidentally: the flight-time of the March 24 test was similar to the on-orbit flight time needed to get from Sunan to the United States via the southern polar route. But that is likely coincidence.

Leaving FOBS aside for the moment: at any rate a missile with this power launched on a more conventional ballistic trajectory can easily reach any location within the continental United States, as well as Europe and the Pacific (but would need a working reentry vehicle of course, which is another matter). In addition to that, it means that North Korea now in theory also has a potential road-mobile reconnaisance satellite launcher in their arsenal.

 

image: KCNA/Rodong Sinmun

image: KCNA/Rodong Sinmun

image: KCNA/Rodong Sinmun

image: KCNA/Rodong Sinmun

 

Added note: some sources are now casting some doubt on the missile identity, suggesting (with arguments from image analysis) that footage from the failed March 16 launch was perhaps presented by North Korea as being from the March 24 launch. The added suggestion is that the March 24 test missile might have been a Hwasong-15, not a Hwasong-17 as North Korea is claiming.

These objections are interesting, but multiple scenario's are possible. For example, they might have used footage from both test launches, certainly if iconic scripted propaganda scenes (e.g. KJU marching in front of the TEL leading his Rocket men) were shot during the preparations for the failed March 16 test. North Korea has been known to have doctored launch imagery for aesthetic/propaganda purposes before in the past, as I have shown for the historic first Hwasong-15 launch of 28 November 2017.

Whatever missile it really was: the missile performance shown by this test is remarkable and well beyond that of earlier North Korean ICBM launches. Western tracking of the missile test confirms the performance, so it is not just North Korean propaganda that can easily be waved away. This is a significant development, no matter how you look at it.

An upcoming Trident-II D5 SLBM test in the Atlantic

click map to enlarge

A few days ago a Navigational Warning (NAVAREA IV 838/21, also issued as HYDROLANT 2336/21) appeared which points to an upcoming Trident-II D5 SLBM (Submarine-Launched Ballistic Missile) test from a US or Royal Navy SSBN on the Atlantic Eastern Missile Range between 12:30 UT on September 17, and 1:23 UT on Sept 20. The distance between the launch area and MIRV target area is about 9900 km.

This is the text of the Navigational Warning (the map in top of this post shows them mapped, along with a simple ballistic trajectory):

151459Z SEP 21
NAVAREA IV 838/21(11,24,26).
ATLANTIC OCEAN.
FLORIDA.
1. HAZARDOUS OPERATIONS 171230Z THRU 200123Z SEP
   IN AREAS BOUND BY:
   A. 28-56N 079-59W, 29-02N 079-53W,
      29-06N 079-37W, 28-59N 079-10W,
      28-37N 079-10W, 28-36N 079-35W,
      28-45N 079-56W.             
   B. 28-24N 076-44W, 28-42N 076-42W,
      28-21N 074-40W, 28-06N 074-44W.
   C. 27-27N 071-21W, 27-52N 071-15W,
      27-25N 068-46W, 26-54N 068-54W.
   D. 17-22N 044-54W, 18-33N 044-32W,
      16-54N 040-55W, 16-00N 041-23W.
   E. 09-00S 003-51W, 08-22S 003-22W,
      12-35S 002-40E, 13-05S 002-19E,
      11-56S 000-16E, 12-09S 000-16W,
      11-34S 000-20W.
2. CANCEL THIS MSG 200223Z SEP 21.

The launch area (area A) is one of two launch areas used for these kind of tests in the Atlantic (see an earlier post from 2019 analyzing several of these launches). It is the variant closest to the Florida coast, one which I suspect is used when the launch has an 'audience' of officials.

The area is close enough to the Florida coast that Florida east coast residents might see the launch, as has previously happened.

The target area is the regular target area in the southern Atlantic some 1000 km out of the coast of Angola.

Areas B, C and D are where the first, second and third stage splash down.

 

 

The location of the hazard areas does not match a simple ballistic trajectory well (such a trajectory is indicated by the line in the map in the top of this post), which might point to some mid-flight manoeuvering of the MIRV-bus.

The test launch is probably a DASO ("Demonstration and Shakedown Operation"), done to recertify the readiness of the submarine and its crew after major overhauls. One candidate submarine for this test launch is the Ohio-class SSBN USS Tennessee (SSBN 734) which reportedly completed a major overhaul at Kings Bay on July 1. [EDIT 18 sept 2021 15:45 UT: it actually was USS Wyoming, which fired two Trident missiles as part of the test]

 

UPDATE 18 Sep 2021 15:45 UT

The US Navy has announced that as part of DASO-31, the Ohio-class SSBN-742 USS Wyoming has fired two Trident missiles on September 17th.

image: US Navy/David Holmes

image US Navy/David Holmes

A possible (now CONFIRMED) Trident-II SLBM test launch between February 9 and 14, 2021 [UPDATED]

click map to enlarge

A Navigational Warning, NAVAREA IV 117/21, appeared yesterday, and is suggestive of an upcoming Trident-II SLBM test in the Atlantic. I have posted on such test launches before.

This is the text of the Navigational Warning:

 071431Z FEB 21
 NAVAREA IV 117/21(GEN).
 ATLANTIC OCEAN.

 1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING
    091340Z TO 140226Z FEB IN AREAS BOUND BY:
    A. 28-56N 76-17W, 28-56N 75-34W,
       28-36N 75-34W, 28-43N 76-17W.
    B. 28-02N 73-18W, 28-17N 73-13W,
       27-47N 71-11W, 27-34N 71-17W,
       27-44N 72-10W.
    C. 26-25N 67-23W, 26-47N 67-10W,
       25-44N 63-47W, 25-06N 63-57W,
       25-32N 65-52W.
    D. 17-10N 45-30W, 17-37N 45-11W,
       16-53N 43-06W, 15-23N 41-22W,
       14-46N 41-42W, 16-11N 44-26W.
    E. 06-00S 09-39W, 05-13S 09-08W,
       06-37S 06-56W, 07-17S 07-22W,
       06-55S 07-57W, 07-00S 08-05W.
 2. CANCEL THIS MSG 140326Z FEB 21.

The map in top of this post shows the hazard areas A to E from this Navigational Warning plotted, and a fitted ballistic trajectory. Together they define what strongly looks like a Trident-II Submarine Launched Ballistic Missile (SLBM) trajectory. 

Area 'A' is the launch area where the submarine is located; areas 'B', 'C' and 'D' is where respectively the first, second and third stages of the missile splash down; area 'E' is the target area of the warhead(s).

The indicated range, from the distance between area's A and E, is about 8400 km. That is somewhat shorter than most earlier Trident-II tests in the Atlantic.

Earlier tests in the Atlantic typically had a range near  9800 km, in one case even 10 600 km (see my overview here). So this test falls short from a  typical test by about 1500 km. 

An earlier clearly shorter range was however indicated for the infamous June 2016 Royal British Navy Trident-II test, which would have had a 8900 km range with a target area west of Ascension Island if it had not failed. The range of the upcoming February 2021 test is 500 km shorter than that of this June 2016 test, with a target area slightly more north and the launch area further out of the Florida coast. 

The launch area is nevertheless a familiar one: one of two areas regularly used for Atlantic Trident test launches. 

It is the same as that for the 10 Sep 2013, March 2016 and June 2018 Trident tests. It is the area labelled 'launch area B' in the map below, which plots the launch areas of several previous Trident tests. The figure comes from this previous post and is discussed there (including a suggestion for why there might be two distinct launch areas).

click map to enlarge

 

The target area near Ascension Island and shorter range might perhaps indicate that this will be a British Royal Navy test with the SLBM launched from a Vanguard-class submarine rather than a US Navy test, but this is by no means certain. It could also mean a US Navy test with new hardware, e.g. a more heavy dummy warhead or a new stage engine.

US Navy tests are usually acknowledged after the test, so it will be interesting to see whether such an acknowledgement will appear from either the US or British Navy.

UPDATE  10 Feb 2021 10:50 UT

Overnight, images and footage have appeared from Florida and Bahama residents that show an exhaust plume, indicating that the test indeed took place, near 23:30 UT on Feb 9. These are a few of them:

Is this what we saw last night from the Leeward end of Provo? This is looking northeast at around 6:31pm yesterday (Feb 9, 2021) pic.twitter.com/yr8ReXUoZe

— Dave Wickert (@DaveWickert) February 10, 2021

JUST IN - Trident missile launched from a submarine just off the coast in South Florida?pic.twitter.com/odlkSaaRPT

— Disclose.tv 🚨 (@disclosetv) February 10, 2021

Strange Object appear in sky 2hrs ago in Palm Beach Florida, did my research & no rocket was launch today either, the next rocket launch is March 25th. #UFO #UFOsighting pic.twitter.com/d5uqmuJFUD

— Nick Thomas (@Mixmasterxl) February 10, 2021

Yippy presents launch footage of Trident II - #SLBM from Bahamas 2/9/2021 @ approx 1830hrs. pic.twitter.com/tqPbh5BZyG

— Yippy.com the best search engine in the world. (@yippycom) February 10, 2021

 

The imagery shows the sun-illuminated exhaust plume of the missile. The missile itself is in space by that time, ascending towards its ~1200-1800 km apogee.

I did a quick calculation: for a launch at 23:30 UT on 9 February 2021, the missile (and its expanding exhaust plume) should break into sunlight about a minute after launch once above ~147 km altitude. I have indicated the sunlit part of the trajectory in the map below in yellow. This means that the exhaust plume on the imagery is from either the second or third stage of the missile.

click map to enlarge

UPDATE 16 Feb 2021:

The Drive reports that the US Navy has now confirmed that this was a Trident test. The name of the submarine from which the missile was launched has not been released.

A reanalysis of the Trident SLBM test of 10 September 2013 and other tests

9 May 2019 Trident-II D5 test launch from USS Rhode Island in front of Florida
Photo: John Kowalski/US Navy

NOTE: This post reanalyses a case from September 2013 that turned out to be a Trident SLBM test launch. New information on the launch trajectory allows to glean information on the missile's apogee. The 10 September 2013 test launch trajectory is compared to those of several other Atlantic Trident test launches in subsequent years. 

Elements of this re-analysis were already published in May of this year in two Twitter threads here and here. As Twitter is highly ephemeral in nature, this blog post serves to preserve and consolidate the two analysis.

*********

On 9 May 2019, I noted a Maritime Broadcast Warning issued for the period of May 9 to 12, that clearly defined the trajectory of  a Trident-II SLBM test in the Atlantic (this was was later confirmed to be a Trident test launch from the submarine USS Rhode Island):

NAVAREA IV 394/2019 

(Cancelled by NAVAREA IV 403/2019)

WESTERN NORTH ATLANTIC.
FLORIDA.
1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING
   091340Z TO 120026Z MAY IN AREAS BOUND BY:
   A. 28-53N 080-01W, 29-00N 079-35W, 28-55N 078-58W,
      28-38N 079-00W, 28-40N 079-37W, 28-50N 080-01W.
   B. 28-34N 076-26W, 28-24N 075-24W, 28-10N 075-27W,
      28-21N 076-29W.
   C. 27-45N 070-22W, 27-14N 068-45W, 26-48N 068-56W,
      27-18N 070-32W.
   D. 17-46N 045-38W, 16-22N 042-18W, 15-44N 042-36W,
      17-09N 045-55W.
   E. 15-47S 004-32E, 17-17S 007-04E, 17-10S 007-08E,
      17-29S 007-49E, 17-20S 007-52E, 17-19S 008-07E,
      17-28S 008-12E, 17-41S 008-04E, 17-45S 008-14E,
      18-27S 007-50E, 17-51S 006-44E, 17-43S 006-50E,
      16-11S 004-16E.
2. CANCEL THIS MSG 120126Z MAY 19.

071718Z MAY 2019 EASTERN RANGE 071600Z MAY 19.

The five hazard areas defined in the Broadcast Warning correspond to: the launch area in front of the coast of Florida; the splash-down zones of the three booster stages;  and the MIRV target area in front of the Namibian coast. This is what it looks like when the coordinates are mapped - the dashed line in the map below is a modelled simple ballistic trajectory between the lauch area and target area:

click map to enlarge

The case brought me back six years, to September 2013, when I was asked to look at photographs made by German astrophotographer Jan Hattenbach that showed something mysterious. I suggested it was a missile test, a suggestion which was later confirmed.

In this blog post, I revisit the 2013 analysis in the light of new information about this test, and compare it to other tests for which I could find trajectory information.

In the evening of 10 September 2013, Jan Hattenbach was making a time-lapse of the night sky near the GranTeCa dome at the Roque de los Muchachos observatory on La Palma in the Canary Islands, at 2300 meter altitude.

Suddenly, a strange fuzzy objects producing cloudy "puffs" moved through the sky. I wrote about it in two blog posts in 2013 (here, and follow-up here), identifying the phenomena as a Trident-II SLBM test launch conducted from a US Navy Ohio-class submarine.

This is Hattenbach's time lapse of the phenomena: the fuzzy cloud moving from bottom center to upper left is the missile (the other moving object briefly visible above the dome is a Russian satellite, Kosmos 1410). The distinct "puffs" are likely the missile's Post-Boost Control System (PBCS) reorienting while deploying RV's during the post-boost phase:





Here is a stack of the frames from the time-lapse, and a detail of one of the frames:

click to enlarge

click to enlarge

At that time, Ted Molczan had managed to dig up a Broadcast Warning that appeared to be for the MIRV target area:

( 090508Z SEP 2013 )
HYDROLANT 2203/2013 (57) 
(Cancelled by HYDROLANT 2203/2013)

SOUTH ATLANTIC.
ROCKETS.
1. HAZARDOUS OPERATIONS 091400Z TO 140130Z SEP
   IN AREA BOUND BY
   09-18S 000-26W, 09-50S 000-32E,
   12-03S 002-39E, 13-40S 004-09E,
   14-09S 003-49E, 13-06S 001-56E,
   11-05S 000-58W, 10-55S 001-05W,
   09-56S 000-50W.
2. CANCEL THIS MSG 140230Z SEP 13.


The case of May this year made me realize there should be Broadcast Warnings for the launch area and stage splashdown zones as well. Searching the database for such Navigational Warnings, I indeed managed to find them, as a separate Broadcast Warning:

( 082155Z SEP 2013 )
NAVAREA IV 546/2013 (24,25,26) 
(Cancelled by NAVAREA IV 546/2013)

WESTERN NORTH ATLANTIC.
ROCKETS.
1. HAZARDOUS OPERATIONS 091400Z TO 140130Z SEP
   IN AREAS BOUND BY:
   A. 28-57N 076-17W, 28-56N 075-54W,
      28-44N 075-11W, 28-29N 075-13W,
      28-43N 076-17W.
   B. 27-53N 073-02W, 28-14N 072-56W,
      27-58N 071-52W, 27-46N 071-08W,
      27-38N 071-11W, 27-39N 071-43W,
      27-39N 071-48W, 27-41N 072-04W.
   C. 26-42N 066-58W, 26-16N 065-36W,
      25-37N 063-38W, 25-18N 063-35W,
      25-06N 063-42W, 25-02N 063-52W,
      25-39N 065-51W, 26-07N 067-12W.
   D. 15-59N 043-47W, 16-51N 043-14W,
      15-54N 040-54W, 14-19N 038-09W,
      13-48N 038-28W, 13-30N 039-26W.
2. CANCEL THIS MSG 140230Z SEP 13.

When the coordinates of these two Broadcast Warnings are mapped, they define a clear trajectory for this test (map below). It is somewhat different from the hypothetical trajectory we reconstructed in 2013 (the launch site is at a different location, much closer to Florida) and it is very similar to that of the recent May 2019 test. The dashed line is, again, a modelled simple Ballistic trajectory between the launch area and MIRV impact area, this time fitting the hazard areas extremely well:

click map to enlarge

The trajectory depicted is for an apogee height of 1800 km. This altitude was found by modelling ballistic trajectories for various apogee altitudes, and next looking which one of them matches the actual sky positions seen in Hattenbach's photographs from La Palma best.

In order to do so, I astrometrically measured Jan Hattenbach's images in AstroRecord, measuring RA and declination of the missile in each image using the stars on the images as a reference. The starmap below shows these measured sky positions, as red crosses.

When compared to various modelled apogee altitudes (black lines in the starmap), the measured positions best match an apogee altitude of ~1800 km:

click starmap to enlarge

So, we have learned something new about the Trident-II D5 apogee from Hattenbach's La Palma observations. At 1800 km the apogee is a bit higher than initially expected (ICBM/SLBM apogees normally are in the 1200-1400 km range).

This is how it approximately looks like in 3D (green lines depict the approximate trajectories of the missile stages). The ground range of this test was about 9800 km:

click to enlarge

Out of curiosity, and now knowing what to look for in terms of locations, I next searched the Broadcast Warning database for more Broadcast Warnings connected to potential Trident-II tests. I found six of them between 2013 and 2019, including the 10 September 2013 and 9 May 2019 test launches. It concerns additional test launches in June 2014, March 2016, June 2016, and June 2018. Putting them on a map reveals some interesting patterns, similarities and dissimilarities:

click map to enlarge

The set of Broadcast warnings points to at least two different launch areas, and three different MIRV target areas.

The two launch areas are in front of the Florida coast, out of Port Canaveral. One (labelled A in the map) is located some 60 km out of the coast, the other (labelled B in the map) is further away, some 400 km out of the coast.

I suspect that the area closest to Florida is used for test launches special enough to gather an audience of high ranking military officials. The recent test of 9 May 2019 belongs into this category, as well as a test in June 2014, and also the infamous British Royal Navy test of June 2016 (I will tell you why this test has become infamous a bit later in this blog post).

As to why area A is tapered and area B isn't, I am not sure, except that the launch location for these tests could perhaps be more defined, restrained by the audience that needs a good, predefined and safe spot to view it.

Click map to enlarge

Not only are there two different launch locations near Florida, but likewise there are at least three different MIRV target areas near Africa.

Four tests, including the 10 September 2013 test imaged by Hattenbach, target the same general area, some 1000 km out of the coast of Angola (indicated as 'impact area 1' in the map below). Two of the tests however target a slightly different location.

click map to enlarge

One of these two deviating tests is the earlier mentioned infamous Trident-II test by the British Royal Navy from June 2016.

This test has become notorious because the Trident missile, fired from the submarine HMS Vengeance, never made it to the target area. Instead it took a wrong course after launch, towards Florida (!)  and had to be destroyed. That test had a planned target area (dark green in the map above) somewat shortrange from the other tests, closer to Ascension island. This is the shortest ground range test of all the tests discussed here, approximately 8900 km, some 1000 km short of most other tests. Incidently, the choice of launch area indicates this failed test had a launch audience, so I reckon some top brass was not amused that day.

The other is the recent 9 May 2019 test. This US Navy test had a target area (red in the map above) some 400 km out of the African coast, further downrange from previous tests. This is the longest range test of all the tests discussed here, with a ground range of approximately 10 700 km, about 700 km longer than the other tests. From the choice of launch area, this test too might have had a launch audience.

The other tests had a range of 9600 to 9900 km. The different ranges could point to different payload masses (e.g. number or type of RV's), different missile configurations, or different test constraints.

There have certainly been many more Trident-II tests than the six I could identify in Broadcast Warnings (e.g. see the list here). Why these didn't have Broadcast Warnings issued, or why I was not able to identify those if they were issued, I do not know.

The Trident-II is a 3-staged Submarine-Launched Ballistic Missile with nuclear warheads. The missile is an important part of US and British nuclear deterrance strategies. The missiles are caried by both US and British Ballistic Missile submarines.

click to enlarge

Edit 23 Oct 2019:
Considering the Trident-II D5 range, the US Navy clearly needs to update it's own 'fact file' here (which at the time of writing lists a maximum range of 7360 km, well short of the distances found in this analysis)

[UPDATED] Where to hide your nuclear missile submarine? (but be quick)

(Updated 20 Dec 2017 23:25 UT with a new plot that includes DSP)

Say, you are the leader of a nefarious country that is in posession of submarines equiped with long range nuclear missiles. You want to launch a stealth missile attack codenamed "Operation Orange Squeeze" on a northern hemisphere Super Power.

Where would you direct your submarine, and where would you best fire you missiles, from the perspective of an as-late-as-possible space-based detection of your missile launches?

The answer came to me today when, after a question by someone (in the context of a war crime investigation), I looked into the current global coverage of the Space Based Infra Red System (SBIRS), the US system of Early Warning satellites that looks for missile launches:

click map to enlarge

The red areas in the map above have an almost continuous coverage by SBIRS satellites (and often by multiple SBIRS satellites at the same time). The dark blue and black areas in the map by contrast have only a few minutes of SBIRS coverage each day, or even none at all.

As you can see, there is a clear gap in coverage in the southeastern Pacific, with lowest coverage in the area near the Galapagos islands. That is where I would park my nuclear missile submarine.

You might have to be quick to pull off your nefarious plan though. A new SBIRS satellite, the fourth satellite in the geostationary component, will launch in January. It wouldn't surprise me if it stops the gap, once operational.

Of course, this map is in fact somewhat deceptive anyway. It only shows the coverage by SBIRS. But there is also the legacy early warning satellite system called DSP (Defense Support System), which still has active satellites, and which is not taken into account here [UPDATE: but see the plot at the end of this post!]. It is less sensitive than SBIRS, but likely will detect your ICBM SLBM launch.

Back to SBIRS. SBIRS is made up of two components, each currently consisting of three satellites (so six in total): three geosynchronous SBIRS-GEO satellites at geostationary altitude, and three SBIRS-HEO satellites (TRUMPET-FO SIGINT satellites with a piggy-back SBIRS package) in 64-degree inclined Highly Elliptical Orbits with two revolutions a day.

click map to enlarge

The map above shows the coverage of the three geosynchronous SBIRS satellites (a fourth will be launched in January). Eurasia, Africa and the western Pacific Ocean has a continuous coverage by these satellites, with central Asia, Pakistan and India (the latter two known nuclear powers) particularly well covered.

The SBIRS-HEO coverage is more variable and depends on the date and time of day, but the system is designed such that at least one of the HEO satellites will have much of the Northern hemisphere in view at any time. Here are a few examples, for various times of the day: note how coverage of the Northern hemisphere is near-continuous (the HEO component also particularly covers the Arctic region well, which is at the edge of the GEO component's coverage).

click maps to enlarge

A SBIRS satellite typically has two modes: there is the scanning mode, which scans the whole visible hemisphere of the earth (as seen from the satellite) for infra-red heat signatures in less than 10 seconds. And there is the staring mode, a more sensitive sensor which can be used to observe a specific region or just detected infra-red event.

In the case of a missile launch, the sensors pick up the heat signal of the missile engine. Because of the large degree of worldwide coverage which the system now provides, an undetected stealth launch of a nuclear missile has become almost impossible.

SBIRS is probably an important source of  Early Warning capacity and information on the recent North Korean missile tests.


UPDATE 20 Dec 2017  23:25 UT:

I now also included the four DSP satellites that are still operational according to the database of the Union of Concerned Scientists. That leads to the following map:

click map to enlarge

As you can see, the gap has become smaller, but a gap is still there. Red October might be lurking in front of the South American west coast.