Tuesday 27 February 2024

A perigee-raising manoeuvre by the North Korean satellite Malligyong-1

Kim Jong Un inspecting a Malligyong satellite under construction in 2023. image: KCNA

On 21 November 2023 (see this earlier blogpost), after two failed earlier attempts, North Korea launched its first military reconnaissance satellite, Malligyong-1 (2023-179A), using its new Chollima-1 rocket. 

Like two civilian predecessors (KMS 3-2 in 2012 and KMS-4 in 2016), it did indeed reach orbit - an initialy 512 x 493 km, 97.43 degree inclined Sun-Synchonous orbit. But: although North Korea in the days and weeks after launch claimed the satellite took images of various US and South Korean Naval bases and  other important locations (such as the White House), it was not clear whether the satellite was really functional

North Korea never made any purported imagery taken by the satellite public, and independent radio trackers never detected any signals from the satellite.

But now we can definitely say the satellite is alive, On February 19, 2024, it initiated the first of a number of successive perigee raising manoeuvers that stepwise brought perigee (the lowest point in its orbit) up from 488 km to 497 km. It can be seen as the stepped "jump" in the red line in the diagram below, which maps the evolution of the apogee and perigee height of the orbit since launch:

click diagram to enlarge


The orbit raise appears to have been performed stepwise, in five increments, starting on February 19/20 and completed by February 24. The net effect was not only a perigee raise, but also a more circular orbit (currently 508 x 497 km).

click diagram to enlarge


The manoeuvre proves that Malligyong-1 is not dead, and that North-Korea has control over the satellite - something that was disputed.

South Korea's Defense Minister Shin Won-sik, commenting on the North Korean satellite, just this week remarked that it: "is currently in orbit. But it is not showing any signs of performing tasks or engaging in reconnaissance activities". Thus suggesting the satellite is not working.

That remark didn't age well: while we indeed currently can not be sure whether the satellite does successfully take imagery, it at least performs orbital manoeuvres, so in that sense it is functional. And to do such manoeuvers, you need to have the satellite under control, including attitude control.

The orbit raising manoeuver comes a bit as a surprise, as the presence of an onboard propulsion system is unexpected. The previous two North Korean satellites never manoeuvered. That Malligyong-1 has means of propulsion, was not something I and many other analysts expected.

Having the capacity to raise the satellite's orbit is a big deal. It means that North Korea, as long as there is fuel left in the satellite, can prolong the satellite's orbital lifetime, by raising its orbit when it gets too low due to natural orbital decay: thus delaying reentry into the atmosphere.

The orbit raise comes at a moment that some western observers expect that North Korea will launch another satellite soon.

Wednesday 21 February 2024

January UK Trident-II D5 SLBM test failed

It probably generated a lot of Stiff Upper Lip and an "Ow well, that is regrettable Old Boy...." from the UK Defense Secretary and the UK Royal Navy Commander that were on scene to witness the test.

For British media (e.g. The Sun here and the BBC here) report that the 30 January Trident-II D5 SLBM test launch from the British Royal Navy submarine HMS Vanguard, on which I wrote earlier here, failed.

From the description of the failure by The Sun, the suggestion is that the first stage failed to ignite after ejection of the missile from the submarine. As a result, it fell back into sea close to the submarine.

A previous British Royal Navy Trident test launch, in 2016, failed as well when the missile veered into the wrong direction after launch and had to be destroyed in flight.

In general, the Trident-II D5 is a reliable missile. The US Navy test-fires Trident SLBM's frequently, and most of their tests reportedly were successful. It just seems the British have bad luck lately.

UPDATE:  Statement by the UK Ministry of Defense to UK Parliament on the matter.

Friday 16 February 2024

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).

Wednesday 14 February 2024

USSF-124, launching the Hypersonic and Ballistic Tracking Space Sensor

click map to enlarge

If all goes well, SpaceX will launch USSF-124 for the US Space Force on 14 February 2024, using a Falcon 9 rocket launching from Cape Canaveral launch pad 40. The launch window opens at 22:30 UTC and runs untill 3:00 UTC.

USSF-124 launches two classified payloads, one built by Northrop-Grumman and the other by L3 Harris, for the Missile Defense Agency. The two satellites are part of their Hypersonic and Ballistic Tracking Space Sensor (HBTSS). 

In addition, the final four of SDA's SDA Tranche 0 satellites are part of this launch too.

The Navigational Warnings related to this launch (see map above) point to launch into a ~38.5 degree inclined Low Earth Orbit. The orbital altitude will likely be around 600 km.

The upper stage of the Falcon 9 will deorbit after 1.5 revolutions, over the Indian Ocean east of Madagascar, some 2 hours and 20 minutes after launch.

The Navigational Warnings are plotted in the map in top of this post. These are the Navigational Warning texts:

090947Z FEB 24
NAVAREA IV 146/24(11,26).
   142230Z TO 150300Z FEB, ALTERNATE
   2230Z TO 0230Z DAILY 15 THRU 20 FEB
   A. 28-38.28N 080-37.18W, 28-45.00N 080-18.00W,
      28-43.00N 080-09.00W, 28-36.00N 080-07.00W,
      28-28.00N 080-20.00W, 28-27.11N 080-31.61W.
   B. 29-58.00N 077-39.00W, 30-42.00N 076-26.00W,
      31-00.00N 075-43.00W, 30-34.00N 075-28.00W,
      30-21.00N 075-53.00W, 29-53.00N 077-35.00W.
2. CANCEL THIS MSG 210330Z FEB 24.//

081626Z FEB 24
HYDROPAC 483/24(61).
DNC 02, DNC 03.
   0056Z TO 0519Z DAILY 15 THRU 21 FEB
   36-40.00S 078-41.00E, 34-50.00S 079-51.00E,
   26-27.00S 060-32.00E, 28-17.00S 059-28.00E.
2. CANCEL THIS MSG 210619Z FEB 24.

Tuesday 13 February 2024

Imaging the X-37B robotic spaceplane mission OTV 7

OTV 7 imaged from Leiden at 12 Feb 2024. Click image to enlarge

In my previous post, I wrote about the first on-orbit detections, by Tomi Simola, of the US Space Force's X-37B space plane mission OTV 7, and how it is in an orbit that is certainly unusual for a space plane.

Yesterday (February 12, 2024) I finally had a clear sky, and an almost near-zenith pass of OTV 7 in the early evening just after twilight. So I could finally image it too

Using the ZWO ASI 6200MM PRO with a 1.2/85 mm lens, OTV 7 showed up well in the imagery, as a reasonably bright object that was not difficult to detect. Above is one of the images, a 10 second exposure near 19:06 UTC while OTV 7 was over Europe at ~6700 km altitude, descending towards perigee.

The orbit is now a bit better constrained, and about  38600 x 300 km at 59.15 degree inclination. Perigee is currently over the equatorial region. The image below shows the orbit, and the orbital position of OTV 7 around the time I imaged it:

click image to enlarge

OTV 7 was several minutes early on one day old elements, meaning it appears to be actively manoeuvering. This fits an X-37B, the previous OTV missions (all to LEO) were also frequently manoeuvering. 

It is possible that the spacecraft is using a continuous thrust ion engine.

In the current Highly Elliptical Orbit (HEO), the orbital velocity at perigee is close to 10.2 km/s, which is 2.4 km/s more than in a Low Earth Orbit (previous X-37B missions all went to Low Earth Orbit). To eventually land the spaceplane, the orbit likely will be circularized first, by lowering apogee drastically, perhaps with the help of aerobraking in perigee, before doing a deorbit and landing.

This is my current orbital fit, which is still up for improvement, based on observations by Tomi Simola, Eelke Visser, Scott Tilley and me:

1 58666U 23210A   24044.12782730 0.00000000  00000-0  00000+0 0    05
2 58666  59.1696   4.0545 7416334 167.8228 233.0020  2.09261279    07

Saturday 10 February 2024

X-37B OTV 7 has been found in HEO!


OTV 7 discovery image by Tomi Simola, Finland  ((c) Tomi Simola, used with permission)

On 29 December 2023 at 1:17 UTC, after several delays, SpaceX launched a Falcon Heavy for the US Space Force with OTV 7, the seventh X-37B Spaceplane mission. Now its payload has been found!

OTV 7 was the subject of much speculation. The use of a Falcon Heavy, and the locations and time windows of related rocket stage splash-down and reentry zones, as well as statements by the US Space Force, indicated it might go into a different, higher altitude orbit than the previous six missions. On this blog, I speculated about a ~74-degree inclined Highly Elliptical Orbit (HEO).

Thanks to the dedicated efforts of Tomi Simola from Finland, OTV 7 has been found on-orbit this week. It is indeed in a HEO orbit, but inclined by 59.1 degrees, not 74 degrees.

Tomi performed a dedicated plane scan using a fixed staring camera. On the night of 7-8 February, he finally nabbed the elusive payload (see the discovery image above), while it was at ~3400 km altitude descending towards perigee. He used a WATEC 902H2 Ultimate camera with a 1.2/50 mm lens and 10 seconds integration.

Subsequent observations show that OTV-7 is in a 38840 x 323 km, 59.1 degree inclined Highly Elliptical Orbit. Perigee is just North of the equatorial region (currently clearly North of it near latitude 30 N, but short after launch it was at a lower latitude near 15 N).

(a Highly Elliptical Orbit (HEO) is an orbit with a low perigee - generally at a few hundred km altitude -  and distant apogee, at 35 000 km altitude or more. As a result, the shape of the orbit is highly elliptical (highly elongated). An object in HEO typically makes two orbital revolutions a day. Due to the shape of its orbit, it spents most of its time in the higher parts of the orbit and a relatively small amount of time near perigee. When apogee is over high latitudes, as is usually the case for these orbits, this allows a long dwell-time over these latitudes with view of a very large area (a full hemisphere when in apogee). HEO orbits are hence the polar equivalents of a GeoSynchronous Orbit (GEO) and often used for communications relay or long-term monitoring of areas. They are a favoured orbit for Communications, SIGINT and Infra-Red missile launch monitoring. The OTV 7 HEO is unusual in that perigee is not over the southern hemisphere).


orbit of X-37B OTV-7 as of 10 Feb 2024. Click to enlarge

The observed orbital plane of the object matches well with a launch from Cape Canaveral on 29 December 1:07 UTC. Together with the fact that the orbit is quite unusual for a HEO object with it's Northern hemishere perigee location, an identification with OTV 7 is very likely.

Propagating the orbit backwards, the suggestion is that, after initial launch into a 51.5 degree inclined low coasting orbit, it was pushed into HEO by a manoeuvre when crossing the descending node, about half a revolution after launch. It subsequently probably manoeuvered a couple of times, adjusting apogee and perhaps also inclination. 

The upper stage probably did a second manoeuvre after payload separation, changing its inclination to 74 degrees as suggested by the shape, orientation and location of the deorbit area from the Navigational Warnings related to the launch.

click map to enlarge

The map above plots the current orbit of OTV 7 propagated back to the day of launch, as well as the estimated initial low coasting orbit.

As can be seen, the OTV 7 orbit after one revolution actually does cross over the deorbit area from the Navigational Warnings: but in an oblique way that does not seem to match the orientation of the area. This is why I believe that the upper stage after payload separation was boosted into a higher inclined orbit. Perhaps as a collision avoidance manoeuvre (but the implied magnitude of the inclination change, 15 degrees, is rather large), perhaps - but that is pure speculation - it might have delivered a second payload to a higher inclination.

Because their orbital inclinations are about half a degree apart, I did look into a possible relation with another odd object launched into an odd orbit recently: USA 310. Their orbits are quite dissimilar though: USA 310 is in a circular MEO orbit inclined by 58.5 degrees, not a HEO orbit. I do note that their orbital planes, even though quite dissimilar, are 90 degrees apart. But most likely, that is coincidence.

click to enlarge

It will be interesting to follow OTV 7, and see whether it changes orbital altitude as often as the missions to LEO did (see this post from a few years ago).

A re-usable space-plane in HEO: who had that in the cards for 2024....?!

Let's see if they can get it back at some point.

Wednesday 7 February 2024

An upcoming Russian SSO launch from Plesetsk

click map to enlarge

Navigational Warnings have appeared pointing to an upcoming Soyuz launch from Plesetsk between February 9 and 13.

The direction of the launch suggests a ~97.4-degree inclined Sun-Synchronous Polar Orbit. If I would guess at the payload, it likely is either a BARS-M or a EO-MKA optical reconnaissance satellite, based on the orbital inclination aimed for.

While I initially interpreted this launch as a possible BARS-M launch, the lack of a deorbit area for a 3rd stage might suggest an EO-MKA instead (the EO-MKA's are prototypes of a small optical imaging satellite). Or maybe it is something new altogether.

Here are the Navigational Warnings:

051945Z FEB 24
HYDROARC 10/24(42).
DNC 22.
   0600Z TO 0800Z DAILY 09 THRU 13 FEB
   70-13.00N 033-11.00E, 70-18.00N 033-49.00E,
   70-12.00N 034-11.00E, 69-54.00N 034-46.00E,
   69-33.00N 034-47.00E, 69-25.00N 034-15.00E,
   69-35.00N 033-37.00E, 69-53.00N 033-05.00E.
2. CANCEL THIS MSG 130900Z FEB 24.

052111Z FEB 24
HYDROARC 12/24(42,43).
DNC 22.
   0600Z TO 0800Z DAILY 09 THRU 13 FEB
   75-59.00N 021-26.00E, 75-50.00N 022-05.00E,
   75-35.00N 022-47.00E, 75-21.00N 022-52.00E,
   75-15.00N 022-13.00E, 75-24.00N 021-29.00E,
   75-36.00N 020-51.00E, 75-53.00N 020-43.00E.
3. CANCEL THIS MSG 130900Z FEB 24.

The map in top of this post shows the two areas plotted: one is just north of Murmansk, the other close to Svalbard. I have not been able to find a matching area for the upper stage deorbit.

Monday 29 January 2024

An upcoming British Royal Navy Trident SLBM test in the Atlantic [UPDATED]

click map to enlarge

Over the past month, there was much anticipation for a (almost certainly) British Royal Navy Trident-II D5 SLBM test in the Atlantic. The arrival of the British nuclear ballistic missile armed submarine HMS Vanguard and several support ships at Port Canaveral in the past weeks suggested as much. Port Canaveral is the home base for such Trident SLBM tests.

And now the corresponding Navigational Warnings have appeared, for the period January 30 - Feb 4.

290215Z JAN 24
   A. 29-00.00N 079-56.00W, 29-05.00N 079-35.00W,
      29-00.00N 079-07.00W, 28-38.00N 079-06.00W,
      28-36.00N 079-33.00W, 28-42.00N 079-52.00W.
   B. 28-28.00N 076-03.00W, 28-19.00N 075-04.00W,
      28-06.00N 075-07.00W, 28-16.00N 076-01.00W.
   C. 27-03.00N 069-40.00W, 27-20.00N 069-37.00W,
      26-58.00N 068-02.00W, 26-43.00N 068-05.00W.
   D. 19-42.00N 050-06.00W, 20-19.00N 049-55.00W,
      19-02.00N 046-24.00W, 18-23.00N 046-46.00W.
   E. 08-32.00N 031-06.00W, 08-39.00N 031-01.00W,
      08-03.00N 028-55.00W, 06-43.00N 027-40.00W,
      05-49.00N 028-16.00W, 05-59.00N 028-34.00W,
      05-25.00N 028-53.00W, 06-25.00N 029-17.00W.
3. CANCEL THIS MSG 040456Z FEB 24.

I have depicted the five hazard zones from this Navigational Warning (also issued as HYDROLANT 214/24, and a re-issue of an earlier warning that had a typo in the coordinates of Area A) in the map in top of this post. Area A is the launch area. Areas B, C and D are the splash-down zones of the first, second and third stages. Area E is the RV target area.

The launch is from one of two standard test firing areas, some 80-90 km in front of the coast of Florida (see also this earlier post). The launch will be visible from Florida, so from previous experience I expect it to generate a number of 'UFO' reports from eyewitnesses who don't know what they are seeing.

The first thing of note is that the range of this test, at approximately 5900 km, is rather short compared to other Trident tests.

That can be seen in the map below, which depicts the RV target area of this test along with the target areas of earlier Trident-II D5 tests fired from the same test launch area 1.

click map to enlarge

Whereas the other RV target areas are at latitudes 9 S to 18 S, the target area for this test is much more north, near latitude 7 N, i.e. a range some 3000-5000 km short of earlier tests. It is effectively about half the range of a typical Trident test.

HMS Vanguard (S28) has recently come out of a long 7.5 years maintenance overhaul and refuel period, and this test likely is part of its recertification as an operational SLBM submarine. The Royal British Navy has four Vanguard-class submarines in active service. Each of them carries 16 Trident-II D5 missiles.

In June 2016, the previous Royal British Navy Trident missile test, a Trident test-fired from HMS Vengeance, went awry when the missile veered into the wrong direction (towards Florida) after launch: according to newspaper The Guardian because if was given wrong trajectory information. It had to be destroyed in flight. That test targetted a target area just east-southeast of Ascension Island. I guess some nervous officials will watch the upcoming launch carefully with their finger on the destruct button.

UPDATE 21 Feb 2024:

The missile test failed, according to UK Media (.e.g. BBC here and The Sun here). It appears that the first stage did not ignite after missile ejection from the submarine. As a result, the missile plunged back into sea close to the submarine. The test was reportedly witnessed by the UK Defense Secretary Shapps and the Commander of the Royal Navy, so I guess there was a lot of Stiff Upper Lip that day, with some "Ow well, that's unfortunate Old Boy...".
A previous UK Royal Navy test launch, in 2016, failed as well (see discussion above in blogpost).

Thursday 4 January 2024

2023 at a glance

click to enlarge

First of all, a Happy, Healthy and Clear 2024 to all the readers of this blog!

The past year has been an active and productive year. I did optical observations on 50 nights, gathering 14069 astrometric positions on 108 objects, of which 73 were classified objects.

2081 of these astrometric positions were obtained (on both classified and unclassified objects) as part of my regular observational activities. 

In addition to these, 6794 astrometric positions were obtained on the SWARM A, B and C satellites, as part of camera and timing accuracy calibrations (see this earlier post). And 5194 astrometric and photometric datapoints were gathered on BlueWalker 3, which - together with data from 2022 - are part of this study published in Nature.

The image in top of this post, shows all 14069 datapoints gathered in 2023 plotted on a star map. Red crosses are from my regular observing activities; blue crosses are data on BlueWalker 3; and green crosses are data on the SWARM satellites. The diagram below shows the distribution of observing nights over the year:


The past year had several personal and observational highlights. These include:

1. My Lecturer position at the Delft Technical University Faculty of Aerospace Engineering became a permanent position

2. I was co-author to this study published in Nature, on the high brightness of BlueWalker 3

3. Observing the RNLAF cubesats BRIK-II, HUYGENS and BIRELAND (see this post)

4. Being filmed for a very nice 40-minute documentary by the Dutch TV program FOCUS about 'War in Space', for which we filmed at the RNLAF headquarters and my home.

5. Being filmed, as one of three specialists, for this very nice short informative video by the 'University of the Netherlands' on 'War in Space', part of an informative web-series called 'Voorkennis' ('foreknowledge'):

6. Recovering several high altitude objects not seen for a while by our network, including USA 310, PAN and several other GEO and HEO objects.

7. Forecasting the reentries of the North Korean satellites Kwangmyŏngsŏng (KMS) 3-2  and 4

8. Forecasting the reentry of the TU Delft cubesat Delfi-C3.


screenshot from the NTR FOCUS tv documentary (me at left, Major Wijnja at right)


Apart from the already mentioned Nature paper, I also published this Conference Contribution on the work of our network of Independent Satellite Observers, the result of partin g in the 2nds NEO and Debris Conference in Darmstadt in January.

I have been in the media several times on topics including Starlink and the war in Ukraine, Starlink and the quick rise of the number of objects in orbit, space debris in general, the reentry of two North Korean satellites, and the Launcher One mishap, as well as a number of missile tests.

During the second part of the year, I had the opportunity to gather data on MEO, HEO and GEO objects while testing a prototype tracking camera that in 2024 will be placed on the roof of the TU Delft Faculty of Aerospace Engineering. The imagesbelow were obtained with this camera.

6U cubesat Huygens imaged on 7 Sept 2023. Click to enlarge

following the movements of PAN/NEMESIS-1. Click image to enlarge

Russian SIGINT satellite LUCH (OLYMP) 2. Click image to enlarge

Friday 8 December 2023

A Missile Defense Test in the NE Pacific on December 11-16 (FTG-12?)

click map to enlarge

Two Navigational Warnings have appeared, NAVAREA XII 841 and NAVAREA XII 845, that together point to a Missile Defense test with a MRBM/IRBM target missile fired from NW of Hawaii towards California, and intercept by a GBI fired from Vandenberg, California. 

The window runs from December 11  to December 16 (2023). Here are the Navigational Warnings:

 061011Z DEC 23
NAVAREA XII 841/23(19).
A. 24-40.00N 164-32.00W, 24-52.00N 164-43.00W,
   24-38.00N 165-07.00W, 24-26.00N 164-57.00W.
B. 27-13.00N 158-33.00W, 27-34.00N 158-49.00W,
   27-07.00N 159-45.00W, 26-44.00N 159-30.00W.
2. CANCEL THIS MSG 161830Z DEC 23.//

070807Z DEC 23
NAVAREA XII 845/23(18,19).
      35-01.00N 121-13.00W, 35-01.00N 120-29.00W,
      34-45.00N 120-29W.00, 34-44.00N 121-13.00W.
      34-35.00N 123-56.00W, 35-07.00N 123-56.00W,
      35-08.00N 121-13.00W, 34-36.00N 121-13.00W.
      34-28.00N 126-07.00W, 35-11.00N 126-09.00W,
      35-12.00N 125-20.00W, 34-29.00N 125-18.00W.
      35-08.00N 137-34.00W, 35-48.00N 128-26.00W,
      33-43.00N 128-13.00W, 32-52.00N 136-37.00W.
      32-59.00N 138-18.00W, 34-45.00N 138-38.00W,
      35-06.00N 135-41.00W, 33-19.00N 135-25.00W.
2. CANCEL THIS MSG 162000Z DEC 23.//

As pointed out by Twitter user @M51_4ever, this could be test FTG-12, planned for the 4th quarter of 2023. It is a Ground Based Interceptor (GBI) test (part of the Ground Based Midcourse Defense (GBMD) system) where only two of the three stages burn, allowing an intercept at closer range (see also here).

The target missile appears to be a MRBM/IRBM fired from (probably) an aircraft in the vicinity of the fantastically named  French Frigate Shoals. The French Frigate Shoals is a reef/atoll in the Northwestern Hawaii islands, about halfway between Hawai'i and Midway, which got its name from the fact that two Frigates from the ill-fated late 18th century French Lapérouse expedition (which is a name that should be familiar to any Jules Verne fans) nearly were lost there.

My interpretation is that the intercept will be about 1000 km out of the California coast, over area D from NAVAREA XII 845 (Area E probably is where stage 2/3 and any remains of the kill vehicle will come down). The target missile will fly some 3300 km before being intercepted (or not: previous tests had an about 1 in 2 miss chance).

In the map in top of this post, blue is the target missile, red the interceptor.

Wednesday 6 December 2023

Navigational Warnings for USSF-52 (X-37B OTV 7) have appeared [UPDATED]


click map to enlarge

revised post, last updated 12 Dec 2023 18:30 UTC

Navigational Warnings (NAVAREA IV 1414/23) have appeared which I believe are for USSF-52, the launch of X-37B mission OTV 7 (see also this earlier blogpost), on December 11.

This is the text of the Navigational Warning

061024Z DEC 23
NAVAREA IV 1414/23(GEN).
   110001Z TO 110431Z DEC, ALTERNATE
   0001Z TO 0431Z DAILY 12 THRU 17 DEC
   A. 28-39.16N 080-37.80W, 29-12.00N 079-57.00W,
      29-10.00N 079-55.00W, 28-36.00N 080-15.00W,
      28-29.00N 080-24.00W, 28-27.60N 080-31.55W,
      28-27.94N 080-31.75W.
   B. 30-30.00N 078-35.00W, 30-58.00N 078-09.00W,
      30-52.00N 077-58.00W, 30-24.00N 078-23.00W.
   C. 36-07.00N 071-37.00W, 38-06.00N 069-34.00W,
      38-17.00N 068-32.00W, 38-13.00N 068-27.00W,
      37-32.00N 068-50.00W, 35-58.00N 071-28.00W.
2. CANCEL THIS MSG 170531Z DEC 23.//

It defines three areas: the immediate launch zone and side booster return corridor (A); the fairings splashdown zone (B); and the core stage return zone (C).

The initial launch azimuth results in an orbital inclination of about 48.25 degrees. I am however inclined to think that a dogleg might be involved at some point, and the real target inclination might be ~64 degrees.

From various leads it was speculated that USSF-52/OTV 7 might go into a high orbit, unlike previous OTV missions which al went to the lower reaches of Low Earth Orbit. Among the reasons for this speculation are the choice for a Falcon Heavy rather than Falcon 9, a mention of "new orbital regimes" in a recent US Space Force news bulletin on USSF-52, and a mention of a GTO orbit in a 2017 procurement document for the launch (see this earlier blogpost).

The core booster return zone is at some 1500 km from the launch site, which is a distance similar to what we have seen with launches into GTO, such as USSF-44. The launch azimuth however clearly does not match a GTO orbit.

But it all does point to a high apogee orbit. This indicates that perhaps a ~64 degree inclined HEO is targetted. No Navigational Warnings have yet appeared for the second stage (but they might appear later, closer to launch [edit 8 December: as they did! see update below]), which could indicate it will stay on orbit, which also points to a high apogee.

All kinds of speculations are possible, up to the possibility of a service/inspection mission to one of the NRO assets in HEO. Looking at the launch window and orbital plane positions, potential targets then could be USA 179 and USA 184. [update: as the apogee looks to be over the southern hemisphere, this does no longer look very likely though)

It will be interesting to see in what orbit it eventually goes, although with all, uncertainty it might be difficult to locate once on-orbit.

The map in top of this post depicts two scenarios: one for direct orbit insertion into ~48 degrees inclined HEO, and one for a ~185 km coasting orbit.  

EDIT: the map below provides a newly developed scenario aiming for HEO.


UPDATE 8 December 2023:

Indeed, a second Navigational Warning, NAVAREA XII 846/23, has now appeared, that seems to define the second stage deorbit zone. It confirms that after launch, at some point a dog-leg is done with the 2nd stage pushing the payload into a higher inclination orbit - the shape and direction of the area suggests a 74-degree inclined orbit.

071019Z DEC 23
NAVAREA XII 846/23(16,17,19).
   110001Z TO 111615Z DEC, ALTERNATE
   0001Z TO 1615Z DAILY 12 THRU 17 DEC
   51-04N 152-41W, 53-27N 141-07W,
   41-40N 136-32W, 38-43N 146-53W  
2. CANCEL THIS MSG 171715Z DEC 23.//

I am not entirely certain about the scenario which follows next: but one scenario that fits is initial launch into a 48-degree inclined low orbit, a brief coast, and then 20-25 minutes after launch, over the NE Atlantic, a burn that doglegs the payload into a 74-degree inclined Highly Elliptical Orbit with apogee near 35188 km. This would have the second stage return to perigee (where it can be deorbitted) over the area defined by NAVAREA XII 846/23 at the end of the first revolution. See map below.

(the trajectory in the map below is so weirdly curved, rather than the usual sinusoid, because it is a ground-projection of the 2.3 rev/day HEO trajectory).

click map to enlarge

The resulting HEO is somewhat unusual: 74 degrees inclined (rather than the typical 64-degree Molniya orbit) and with apogee over the southern hemisphere. I am not sure my reconstruction is correct and am open to other suggestions.

USSF-52 OTV 7                for launch on 11 December 2023 01:18 UTC
1 70000U 23999A   23345.07222222  .00000000  00000-0  00000-0 0    08
2 70000 074.0000 314.2121 7272705 135.6501 359.9903 02.32559366    04

Launch time will reportedly be 01:18 UTC (December 11)

SECOND UPDATE, 11 Dec 19:00 UTC:

The launch has slipped one day, to 12 December 1:14 UTC. And I have revised my orbit estimates, based on new Navigational Warnings (specifically NAVAREA XII 854/23), that put new time constraints that might indicate that the apogee altitude that is higher than my initial estimate:

USSF-52 OTV 7                  for launch on 12 Dec 2023 01:14:00 UTC
1 70000U 23999A   23346.07013889  .00000000  00000-0  00000-0 0    06
2 70000 074.0000 325.5453 7407989 135.5462 360.0000 02.15472011    09

This orbit has the second stage arrive over what I interpret as the second stage deorbit area around the opening time of  Navigational Warning NAVAREA XII 854/23 (corrected for the shift in launch time between December 11 and 12):

081805Z DEC 23
NAVAREA XII 854/23(16,17,19).
   111253Z TO 111354Z DEC, ALTERNATE 
   1252Z TO 1354Z DAILY 12 THRU 17 DEC 
   51-34.00N 141-57.00W, 49-51.00N 150-42.00W,
   40-55.00N 146-02.00W, 42-38.00N 138-36.00W.
3. CANCEL THIS MSG 171454Z DEC 23.

The resulting orbit with apogee near 37700 km has a daily precession of 4m 22s, matching the 4-minute shift in launch time between december 11 and 12.

This is the resulting trajectory (see also earlier discussion above):

click map to enlarge

Below is the approximate initial coasting orbit, before the dogleg to HEO: I slightly revised it to an orbital inclination of 51.5 degrees so that it lines up better with the core stage return area C (my initial estimate was based on Area A only):

USSF-52 initial parking orbit  for launch on 12 Dec 2023 01:14:00 UTC
1 70001U 23999A   23346.05138889  .00000000  00000-0  00000-0 0    03
2 70001 051.5000 354.4138 0011414 048.2332 322.9851 16.30015116    06

Note that this all strongly hinges on whether the area defined by NAVAREA XII 854/23, south of Alaska, is indeed related to USSF-52 and not something else...



The launch was again postponed and is now slated for no earlier than 14 December 1:13 UTC.

Here are revised elset estimates:

USSF-52 OTV 7                  for launch on 14 Dec 2023 01:13:00 UTC
1 70000U 23999A   23348.06875000  .00000000  00000-0  00000-0 0    08
2 70000 074.0000 315.9156 7272705 135.6501 359.9903 02.32559366    00

USSF-52 coasting orbit         for launch on 14 Dec 2023 01:13:00 UTC
1 70001U 23999A   23347.05069445  .00000000  00000-0  00000-0 0    05
2 70001 051.5000 355.1488 0011414 048.2332 322.9851 16.30015116    02

click to enlarge

Saturday 25 November 2023

North Korea's Malligyong-1 satellite and imaging Guam [UPDATED]

image: KCNA


Colin Zwirko of North Korea News brought the image above to my attention. It accompanies a KCNA news bulletin about a visit of Kim Jong Un to the NADA Control Center in Pyongyang, on November 22, about half a day after launch of the Malligyong-1 satellite.

Colin pointed out that you can just make out what appears to be a satellite ground-track on the blurred map on display in the control center.

In the KCNA bulletin, it is claimed that KJU, during his visit to the center:

"watched the aerospace photos of Anderson Air Force Base, Apra Harbor and other major military bases of the U.S. forces taken in the sky above Guam in the Pacific, which were received at 9:21 a.m. on Nov. 22."

At 9:21 am local time in Pyongyang (00:21 UTC) on November 22, Malligyong-1 was indeed just appearing over the horizon at, and coming in radio reach of, NADA Control Center, having passed over Guam seven minutes earlier, near 9:18 local time in Pyongyang (00:18 UTC). At 9:25:27 local time (00:25:27 UTC), the satellite was closest in range to the NADA Control Center (I mention this as it becomes relevant later).

These three images below show the ground-track and position of Malligyong-1 and its footprint (the area that has the satellite above the local horizon) for the moment it passed over Guam (00:18 UTC); for the claimed moment North Korea received images (00:21 UTC); and for the moment of closest range to the NADA Control Center (00:25:27 UTC):

So theoretically, it is indeed possible that Malligyong-1 made images of Guam near 00:18 UTC, and relayed these to the NADA Control Center a few minutes later, starting around 00:21 UTC when it came into radio reach of the latter.

(note added 3-12-2023: this could perhaps indicate it only broadcasts a signal when in range of Pyongyang. This would explain why people like Scott Tilley and me have not been able to find it active in radio frequencies: it is imperative that radio operators in Japan and South Korea try if they can find it active. First try the lower reaches of UHF, i.e. 400-500 MHz, as that is where for example the Iranian Nour satellites broadcast and we know there are connections between the N-Korean and Iranian rocketry programs).

The line on the map on display in the NADA Control Center in the KCNA image conforms to the Malligyong-1 pass in question. A bright dot on the track over the Sea of Japan seems to closely conform to the point of closest range to NADA CC, around 00:25:27 UTC (see also the animated GIF further down in this blogpost):

click to enlarge

Compare to this map I made of the Malligyong-1 ground-track around that time:

click map to enlarge

In this animated GIF, I have superposed both maps, showing the match:

This however does not necessarily mean that North Korea indeed obtained imagery of Guam on this pass, as is claimed in the KCNA bulletin.

Usually, a satellite goes through a checkout-phase first before becoming fully operational. Solar panels and antenna's have to be unfurled, systems started up and checked, attitude and pointing brought under control, camera's calibrated. This check-out phase usually takes days to weeks. Having imagery within hours, would be quite fast.

So unless North Korea publishes the imagery, it remains conjecture whether the claim is true or just propaganda.

One final thing to remark: if the image in the NADA Control Center was indeed taken during KJU's visit around 10 am local Pyongyang time (according to KCNA) on November 22, this means it was taken before orbits of Malligyong-1 became publicly available. The first public available, US released orbit is of epoch 00:14 UTC on the 22nd, but was not released untill 3:26 UTC, some 2.5 hours after KJU's visit and, it appears, some two hours after the image in the NADA Control Center was taken.. 

click to enlarge

Two clocks are visible in the photograph that would indicate it was indeed taken during KJU's visit, around 1:17 UTC, and therefore before public release of orbital elements: one partial clock can be seen on the right, marking "10:.." in likely local time, the other on the left can be seen in full and is marking "01:17" in what is likely UTC (maybe someone fluent in Korean could confirm what the Korean text above the clock says?).

The image would then date to about 1 hour after any imagery of Guam was obtained.

The orbit on the map in the NADA Control Center conforms to the real orbit in detail, suggesting (if we take face value that the photograph was taken at 01:17 UTC) that North Korea did have either their own tracking data or a telemetry-derived orbit already before the US tracking network published the first public orbits. (while some might say this is perhaps not surprising, and I agree, I mention it because there are still those who question any indigenous capacity North Korea might have when it comes to their missile and space program)

It is of course possible that the image in reality was shot at a later moment, after the orbital elements were publicly released, and the clocks doctored (I mention this as North Korea has a history of doing this kind of stuff).

UPDATE 27 Nov 2023:

On November 25, a new KCNA bulletin mentions a second visit of Kim Jong Un to the NADA Control Center that day where he "watched the photos of major target areas in the enemy region, including Jinhae, Pusan, Ulsan, Phohang, Taegu and Kangrung, taken by the reconnaissance satellite from 09:59:40 to 10:02:10 a.m.".

Specifically are mentioned, photographs: 

"taken by the reconnaissance satellite at 10:01:10 shows the U.S. Navy nuclear carrier Carl Vinson, which is anchored at the military port in Ryongho-dong, Nam-gu of Pusan City"

...and photographs of the: 

"naval base in the Pearl Harbor, the Hickam air-force base in Honolulu and other objects, taken by the reconnaissance satellite while passing over Hawaii of the U.S. at 05:13:22 a.m. on Nov. 25 in Pyongyang time"

Again, the quoted times match the closest approach points on actual passes over/near these targets, as can be seen in the maps below. And the USSN Carl Vinson is in Busan (Pusan) harbor, as Jeffrey Lewis pointed out on Twitter (this does not necessarily mean they have this info of satellite imagery of course).

(in the maps below, quoted times and dates are in UTC. To get Pyongyang local time, add 9 hours).

click map to enlarge

click map to enlarge

Wednesday 22 November 2023

North Korea successfully launches the Malligyong-1 reconnaissance satellite

image: KCNA


On 21 November 2023 at 13:42:28 UTC, according to the State News Agency KCNA, North Korea succesfully launched its new Malligyong-1 military reconnaissance satellite to orbit. The launch was from Sohae platform 2 using a (also new) Chollima-1 rocket. 

This was the third launch attempt. Two earlier attempts, on May 31 (see this blogpost) and August 23 (see this blogpost) failed to reach orbit due to malfunctions of respectively the second and third Chollima stages.

Yesterday's sucessful launch happened 1h 18m before the window from the published Navigational Warning HYDROPAC 3667/23 (see earlier blogpost here) opened, hence taking everybody by surprise.

KCNA reports that orbit insertion was at 13:54:13 UTC.

The US Military Space Tracking network CSpOC has published orbits for two objects resulting from this launch, confirming the North Korean claim of a successful orbit insertion

Object A (nr 58400, 2023-179A) is likely the payload, Malligyong-1, and is in a 97.43 degree inclined, 512 x 493 km sun-synchronous orbit

Object B (nr 58401, 2023-179B) is likely the Chollima-1 upper stage and is in a 97.41 degree inclined, 512 x 467 km orbit.

The orbit of the payload is a Sun-synchronous orbit with a repeating ground track. It results in daily transits over Pyongyang around 10:00 and 22:00 local time, with a ground track that repeats itself each five days. This is consistent with a function as an optical reconnaissance satellite.


I analysed the orbital trajectory in relation to the positions of the hazard zones from Navigational Warning HYDROPAC 3667/23. 

Earlier this year, in connection to the first launch attempt, there was a discussion whether: 

(1) a multiple dogleg was involved, or;

(2) a direct orbit insertion with post-separation restart and dogleg manoeuvering of the second stage, or;

(3) a dogleg manoeuvre of the second stage pre-separation with insertion into a 78-degree inclined non-SSO orbit. 

The reason for the discussion, was that the splashdown area for stage 2 east of the Philippines, was out of line with the splashdown areas for stage one and the fairings. The direction marked by the splashdown areas for the first stage and fairings would actually match a direct SSO insertion. A detailed discussion of the issue is in this previous blogpost on the May launch attempt.

We now have an answer, based on the position of the orbit at orbit insertion: a double dogleg by both the second and third stages was involved, as illustrated below:

click map to enlarge

After separation from the first stage, stage two made a dogleg eastward. After separation from the second stage, stage three then made another dogleg westward, and next brought the payload to the orbit insertion point, the stage itself also attaining orbit in that process (where it is now space debris).

(note: the manoeuvers were likely a bit less 'sharp' than in the illustration above)

The resulting orbit is basically what would have been achieved with a direct insertion along the original launch azimuth, but with the RAAN shifted by 4.2 degrees. The double dog-leg was probably chosen to avoid the second stage falling too close to the Philippines or (in case it underperformed) on China or Taiwan.

[update] Some interesting footage has appeared on the internet from a South Korean all-sky meteor camera operated by Yonsei University. It shows the first and second stage, with the first stage blowing up after separation of the second stage. This could well have been deliberate (to avoid intact hardware recovery by South Korea: or because of range safety), but can also have been accidental (see for example how the Starship stage 1 accidentally blew up just a few days earlier). [end]

Here are a few photo's of the launch, from the North Korean State News Agency KCNA:

"Thar She Goes! No Kablooih this time!"