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.