Tuesday, 10 January 2023

The reentry of the second stage of LauncherOne "Start me Up" seen from Lanzarote

(footage by Ramón López,SPMN Lanzarote)

The footage above was filmed last night near 23:19 UTC (Jan 9) by one of the Spanish SPMN's meteor stations, that of Ramón López ("Stargazer Lanzarote") at Playa Blanca, on the island of Lanzarote in the Canary Islands,

It shows the sad ending of Virgin Orbit's failed "Start Me Up" launch (see my previous post). The moving object that can be seen burning up in the atmosphere in the left corner, is in fact the reentry of the NewtonFour upper stage from the LauncherOne rocket. This happened some 10 minutes after launch.

Below is a stack of the video frames (from the original video, kindly made available to me by the SPMN):


click to enlarge

The timing, viewing direction (W-NW), and direction of movement match well with the launch trajectory for the "Start me Up" mission, which passed about 380 km to the west of Lanzarote. 

The low sky elevation also shows that the object is in fact well below orbital altitude, consistent with reentry into the atmosphere. Had it been in the 555 km altitude orbit aimed for, it would have passed much higher in the sky as seen from Lanzarote, and been invisible, as that part of the orbit was not sun-illuminated. The fact that it is visible, alreadsy shows it was burning up by this time, creating the slow fireball visible in the video.

The event is too far south in latitude to be the first stage, which had a designated splash-down area some 400 km out of the coast of Portugal, 1000 km to the north of Lanzarote. 

Hence, it must be the second stage and attached payloads. The event starts around the time the last engine burn should have ended: the launch, at 10.6 km altitude just southwest or Ireland, was at 23:09 UT and the engine burns of both stages in total should have taken 9 minutes.

So, from the available evidence it looks like the second stage of the rocket underperformed. The fact that it reentered 1000 km to the south of the splashdown area for the first stage to me however suggests that it did initially fire.

As a result of the underperformance, the nature of which still has to be established, the rocket did not gain sufficient speed to bring the payloads to orbit: instead, after briefly reaching Space it went down again on a ballistic trajectory, reentering and disintegrating into the atmosphere - along with the payloads - some 500 or so km to the northwest of Lanzarote, roughly in the area indicated by the yellow ellipse in the map below.


click map to enlarge

The bearing of the point where the fireball disappears in the video, crosses the launch trajectory near 30.03 N, 17.28 W, some 360 km West-Noordwest of Lanzarote about halfway between the islands Madeira and La Palma.

The rocket stage and payloads most likely will have completely burned up during the reentry. If any parts survived at all, they are now on the bottom of the Atlantic Ocean.

Virgin Orbit itself also points the finger to the second stage as the culprit of the failure to reach orbit.


UPDATE (12 Jan 2023):  according to Virgin Orbit, the cause of the failure was indeed a premature shutdown of the second stage. It happened during the first of two planned burns of this stage, at an altitude of 180 km.

Sunday, 8 January 2023

A first launch to orbit from Northwest Europe on January 9 [UPDATED]

click image to enlarge


If there are no launch delays, Virgin Orbit will conduct the first ever launch to orbit from Northwest Europe on January 9.

Dubbed "Start Me Up", the launch will be carried out above the Atlantic just southwest or Ireland. The two-hour launch window opens at 22:16 UTC (23:16 CET) on January 9, 2023.

The launch is airborne, and the launch vehicle is a LauncherOne rocket carried by the Boeing 747-400 'Cosmic Girl' , which will depart from Spaceport Cornwall in Newquay, UK and then fly to the launch zone southwest of Ireland.

The launch will be into a ~97.6 degree inclined, ~550 km Sun-Synchronous orbit. I estimate this approximate initial orbit:

START ME UP                      for launch on 9 Jan 2023 22:16:00 UT
1 70000U 23999A   23009.92777778  .00000000  00000-0  00000-0 0    00
2 70000 097.6000 244.4122 0003607 140.5188 325.8313 15.04676410    02

[Note added: it appears that the 22:16 UTC time is actually the time the aircraft departs from Spaceport Cornwall. Launch will be about an hour later. The elset above can be adjusted to the actual launch time using my TLEfromProxy software]

The map below shows the launch trajectory, and the two hazard zones published for this launch (Maritime Navigational Warnings HYDROLANT 33/23 and HYDROLANT 37/23). The first stage will splash down some 400 km out of the coast of Portugal. 

click map to enlarge

Unfortunately, a launch at this time of the night in this season means that the initial launch trajectory will not be sun-illuminated, which in turn means that any exhaust clouds produced will not be visible in the sky.

However, for the duration of the engine burns itself, the rocket might be visible on ascend to orbit as a moving dot of light (disappearing as soon as the rocket engines cut off, some 9 minutes after launch). 

Southwest Ireland, being closest to the launch area, has the best viewing opportunity: the rocket will move from the southwest to south-southwest, roughly between azimuth 240 and 200 degrees, and reach a maximum sky elevation of about 35 degrees near azimuth 220 degrees (southwest), based on an estimate of the launch trajectory.

The rocket engine burn might also be visible from the southwest of the UK (particularly Wales and Cornwall) and the Atlantic coast of France (Bretagne), as well as NW Spain and Portugal. I have no idea how bright it may be though, i.e. I have no idea whether it will or will not be visible by the naked eye.

From Cornwall it might reach a maximum elevation of  25-30 degrees in the SW, and from Bretagne in France some 20 degrees due West. From NW Spain, the rocket might rise up to almost 50 degrees maximum elevation due West before burning out.

From the Netherlands, where I live, the launch in theory could be visible, but the rocket will stay below 12 degrees maximum sky elevation.  

Below is a diagram of the approximate trajectory I predict as seen from the SW Dutch coast (Zeeland Province, some 1000+ km from the launch area): times given are in minutes after launch.

click diagram to enlarge


"Start Me Up" will launch seven nine  eight payloads, including several payloads for the UK Ministry of Defense. Virgin Orbit has conducted two four earlier successfull launches so far.

click map to enlarge


The launch happened at 23:09 UTC but unfortunately failed to reach orbit because of an anomaly with the second stage. For more information, including a video of the reentry as observed from Lanzarote in the Canaray Islands, see this follow-up post.

Saturday, 7 January 2023

2022 at a Glance

the astrometric positions I obtained in 2022 plotted on a starmap


The plot above shows you 2022 at a glance: all 938 positional measurements for orbit determination I did last year plotted on a sky map

In 2022, I observed on 21 nights (all in the period of April to September 2022), and obtained astrometry on a total of 52 different classified objects (often multiple times) plus 9 unclassified ones. All but one were objects in Low Earth Orbit this time - without intent I neglected GEO and HEO objects in 2022, but I hope to pick up coverage of those again in 2023.

In addition to astrometry (positions for orbit determinations), I also gathered a large number of photometric measurements (data on brightness variations), on Bluewalker 3 (2022-111AL) and on the Kosmos 482 Descent Craft (1972-023E, see the article I wrote on this object here).

Regarding photometry on Bluewalker 3, my data are part of this analysis, and I have become an affiliate member of the new IAU Centre for the Protection of Dark and Quiet Sky from Satellite Constellations Interference (CPS) in connection to these activities.

2022 was a weird year for me personally. Halfway through the year I transfered from Leiden Observatory (i.e. the Leiden University dept. of Astronomy) to Delft Technical University, as - against my own expectations - I landed a job as Lecturer in Optical Space Situational Awareness at the section Astrodynamics and Space Missions of the Aerospace Faculty at Delft Technical University (see my June blogpost here). I started in this new position (that should become a permanent position in June 2023 if I satisfy my employers) on June 1. 

Optical SSA is new for the TU Delft: together with my new colleague Steve Gehly I will be creating a new addition to the teaching and research curriculum of the faculty. That prospect is both terrifying and exciting - it is still incredible to me that I now will be teaching the stuff I once started as an 'amateur' on a University! I guess the academic career change from Archaeology to Space is final now.

During the last months of 2022, starting in the new job, including working on a couple of project proposals and finishing the FOTOS 2 project for the Royal Netherlands Air Force, took much of my time and energy.

Among the special interest objects observed in 2022 were, on the unclassified end:

- the Boeing Starliner CST-100 OFT-2

- Bluewalker 3 (2022-111AL)

- China's new experimental 'Space Plane', 2022-093A

- Kosmos 2558 (2022-089A, covertly stalking USA 326

- the Kosmos 482 Descent Craft ( I published a paper on this unique object in The Space Review in May 2022)


Boeing Starliner CST-100 OFT-2 and the ISS, just before docking on May 20, 2022

On the 'classified' end, there were three classified launches where I (usually in unison with Cees Bassa) managed to do the very first optical observations on these objects, a few revolutions after launch:

- NROL-85 (2022-040A, USA 327) in April.

- USA 328-331 (2022-064B-F), 4 objects covertly launched in June.

- NROL-91 (2022-117A, USA 338) in September.


first optical observation of NROL-91 (USA 338), on 25 Sept 2022

I covered two uncontrolled reentries of the massive CZ-5B core stages from the launches of the Wentian and Mengtian modules to the Chinese Space Station (CSS) in July and October with reentry predictions, leading to some media attention as well (it also lead to an episode where I became the target of State sponsored trolling).

I was interviewed by NBC Nightly News in August for an item about Kosmos 2558 stalking USA 326. I also was on Dutch national  television twice, once in March in an RTL-Z news item about Starlink, and once in October in a Nieuwsuur (NPO) item about Elon Musk, Starlink and the war in Ukraine.

I have also been giving several interviews and sollicited opinions in the written press (domestic and international) on various space-related topics, but didn't keep a tally of those.

Apart from spacecraft, I also analysed a number of North Korean and US Ballistic Missile launches the past year.

Wednesday, 12 October 2022

The North Korean Medium Range Missile test of October 3rd

click to enlarge

On October 3rd (October 4th local time in Korea) at 22:22 UTC, North Korea launched an MRBM from Mupyong-ri. They fired it over Japan on a normal ballistic trajector, instead of on a highly lofted trajectory, causing consternation and air raid alarms to go off in northern Japan. 

Firing a missile over Japan had not happened since the two Hwasong-12 launches in August and September 2017 (see earlier blog posts here and here). 

Western military sources indicate a range of approximately 4600 km and an apogee at approximately 1000 km. This is at the upper theoretical  limit of the Hwasong-12 MRBM.

Photographs of the launch were released (along with images of several other launches of SRBM and SLBM from the past weeks) by the North Korean State Press Agency KCNA on October 10. The surprise aspect of the images was that it seems to show a missile that is somewhat different in outlook than the Hwasong-12 we know, i.e. something new.

October 3 MRBM launch (image KCNA)

October 3 MRBM in flight (image KCNA)


In the image below, I have put an image from the Hwasong-12 launch from earlier this year, January 29, launched from the same location (Mupyong-ri), next to the October 3 launch. Below it are the outlines of the two missiles as traced from the photographs.

There are subtle differences, as several people (a.o. Nathan Hunt, Ankit Panda and me) have noticed. The missile overall seems similar in length and diameter, but the nosecone with RV  looks different in shape, and the first/second stage might actually be slightly taller than that of a Hwasong-12. And while the Hwasong-12 we know has a flared base of the first stage, the new missile seems to have a beveled base. In-flight images suggest it has one single engine only, whereas the Hwasong-12 we know has four Vernier engines in addition to the main engine, as does the Hwasong-14.

So this looks to be a new missile (or a new version of the Hwasong-12 or Hwasong-14).

The trajectory it has flown is longer than that of the previous two Hwasong-12 launches over Japan in August and September 2017, as can be seen in the image below. This might also point to a new missile, or a clearly improved single-engine version of the Hwasong-12 or Hwasong-14.


click to enlarge

image KCNA


Among the images released by KCNA is one showing Kim Jung Un looking at a computer screen depicting a missile trajectory (see image above). I rectified the map shown on the screen and georeferenced it to an equal-area map (see below), yielding the trajectory below which matches well with a 4500 km trajectory (from the map I measure a range of ~4560 km, but given the error margins in processing this map, that basically is ~4600 km):

click to enlarge

The yellow dashed line (which was added by me as an overlay, as are the country outlines in black and yellow annotation) shows what a real ballistic trajectory would look like.

If the trajectory diagram is to scale hirozontally and vertically, then apogee should have been ~1300 km, slightly more than the ~1000 km quoted from western military sources.

The impact point of the missile is at 34.6 N, 178.3 E, close to the International Date Line. While passing over the Japanese islands, it was at an altitude of about 740-750 km, ascending towards its apogee.

From the launch images, the launch site is the same as that of the January 29 Hwasong-12 launch earlier this year: the Mupyong-ri facility (see earlier blog post here) at 40.6112 N, 126.4257 E. The treeline and pavement, and small side road, is very recognizable. The same location also saw the first successful Hwasong-14 launch on 28 July 2017 (the Hwasong-14 is a two-stage version of the Hwasong-12). If the October 3rd launch indeed is a new missile, as it looks to be, then this facility has now seen launches of three different MRBM's: Hwasong-12, Hwasong-14 and this new missile.

Tuesday, 4 October 2022

PAN is moving back westwards again


click diagram to enlarge

In September 2021 I wrote a blogpost noting that the enigmatic geosynchronous SIGINT satellite PAN/NEMESIS I (2009-047A) had left 47.7 E and was drifting eastwards. By 30 August 2022 it had drifted as far as 63.1 E.

But somewhere in September 2022, it reversed its drift and started to move Westwards again. Greg Roberts in South Africa recovered it on 30 September 2022 at 55.7 E after he looked for it in vain at more eastward positions.

From tracking data over the period May 2021 - August 2022, PAN was drifting eastwards at a rate of about 0.27 degrees/day. The drift started late February 2021.

It subsequently must have rapidly moved West again, by at least 0.23 degrees/day. It is not clear yet whether the drift continues, or if it is now stable at 55.7 E. Future observations will tell.

At the time of the eastward drift, I was not sure whether the drift was deliberate or the result of an operational "end-of-life". With the halt of the drift and subsequent rapid move westwards this month, it seems to me that the drift was deliberate and the satellite is still operational.

PAN/NEMESIS I was launched in 2009 and is a SIGINT satellite with a very unusual role. As the diagram in top of this post shows, it frequently relocated between late 2009 and late 2013 (which was very unusual), stalking a number of commercial communications satellites and eavesdropping on them. By 2014, this behaviour suddenly stopped, and for a long time it was kept at a stable position near 47.7 E, untill it started to drift in February 2021.

Six years ago I wrote an in-depth article on this enigmatic satellite for The Space Review that you can read here.

Monday, 3 October 2022

A pass of China's Space Plane

click to enlarge

China's experimental Space Plane, 2022-093A, imaged over the roof of my house in Leiden in the evening of  October 2, while it was making a low pass (36 degrees elevation max).
Canon EOS 80D + Samyang 1.4/35 mm lens at F2.0, 4 second exposure at ISO 800.

Sunday, 25 September 2022

USA 338, the NROL-91 payload, observed

NROL-91. Click image to enlarge

On 24 September 2022 at 22:25:30 UT, with half an hour delay, ULA launched NROL-91, a Delta IV Heavy with a classified payload for the NRO. The payload is probably an electro-optical reconnaissance satellite in the KH-11 lineage (for more backgrounds see the previous post).

Six hours after the launch, the payload, USA 338, made a pass over the Netherlands and around 4:17 UTC (6:17 local time) was observed by Cees Bassa from Dwingeloo and by me from Leiden. It was visible by the naked eye with a brightness around magnitude +2.5 to +3.

The image above shows it ascending over the roof of my house, passing close to the Hyades cluster in Taurus. The image was taken with a Canon EOS 80D + Samyang 1.4/35 mm lens, 5 seconds at ISO 800. The sky was clear but with sacttered clouds, as can be seen in the image.

A very preliminary orbit fit suggests a 73.59 degree inclined, 376 x 415 km orbit. The RAAN difference with USA 290, an earlier launch of similar type, is ~99 degrees. When the orbit gets better established, these figures might still change somewhat.


Wednesday, 21 September 2022

NROL-91: a new (possibly electro-optical) sister ship of USA 290


click map to enlarge

On 24 September 2022 at 21:53 UT, an ULA Atlas Delta IV Heavy (the last to be launched from Vandenberg) will launch from Vandenberg SFB Launch Complex 6 as NROL-91, carrying a classified payload into Low Earth Orbit for the NRO.

The launch is in southernly direction. The locations of the four hazard areas from the published Navigational Warnings (see map above and text below) are consistent with launch into an orbital inclination of 73.6 degrees, which is similar to NROL-71 from January 2019 that launched USA 290 (2019-004A). 

So the NROL-91 payload likely is a sister ship to USA 290.

Below is Navigational Warning HYDROPAC 2592/22 for the launch (note that there appears to be a clerical error in the first coordinate of area C):

122224Z SEP 22
HYDROPAC 2592/22(GEN).
   A. 242020Z TO 242347Z SEP, ALTERNATE
      2020Z TO 2347Z DAILY 25 THRU 27 SEP
      33-53.00N 120-23.00W, 34-28.00N 120-40.00W,
      34-39.00N 120-40.00W, 34-39.00N 120-35.00W,
      34-27.00N 120-25.00W, 33-55.00N 120-18.00W.
   B. 242020Z TO 242345Z SEP, ALTERNATE
      2020Z TO 2345Z DAILY 25 THRU 27 SEP
      25-18.00N 117-07.00W, 25-12.00N 117-27.00W,
      26-35.00N 117-53.00W, 26-41.00N 117-33.00W.
   C. 242020Z TO 242345Z SEP, ALTERNATE
      2020Z TO 2345Z DAILY 25 THRU 27 SEP
      00-17.00S 121-28.00W, 00-07.00S 110-21.00W,
      03-24.00S 109-33.00W, 03-24.00S 110-21.00W.
   D. 242242Z TO 250133Z SEP, ALTERNATE
      2242Z TO 0133Z DAILY 25 THRU 27 SEP
      17-57.00N 140-23.00W, 06-13.00N 137-52.00W,
      06-30.00N 136-25.00W, 18-15.00N 138-53.00W.
2. CANCEL THIS MSG 280233Z SEP 22.// 

A second Navigational Warning for this launch, NAVAREA XII 695/22, is identical.

The locations of the first three hazard areas A to C from the Navigational Warning are indeed very similar to those for NROL-71 in 2019: compare for example to this map for NROL-71 from this december 2018 post:


NROL-71 from January 2019. click to enlarge

Area D, the upper stage deorbit area, is situated slightly more south and is a bit more elongated than it was for NROL-71, for unclear reasons. The upper stage deorbit happens at the end of the first revolution. The deorbit burn might be visible from central Asia around 23:10-23:20 UTC.

In 2019, NROL-71 was launched into a 395 x 420 km, 73.6 degree inclined non-sun-synchronous orbit and I expect the orbit of the NROL-91 payload to be very similar.

Here is my pre-launch orbital estimate for the NROL-91 payload based on this assumption:


NROL-91                      for launch on 24 Sep 2022 at 21:53:00 UT
1 70001U 22999A   22267.91180556  .00000000  00000-0  00000-0 0    06
2 70001 073.6000 044.7175 0018421 155.1634 324.7303 15.53162541    00


If NROL-91 indeed launches at 21:53 UT on the 24th, the orbital planes of the payload and USA 290 will end up at a 90-degree angle to each other, as can be seen in the polar view below:

polar view of the orbital plane relative to that of USA 290. Click to enlarge


If the launch is scrubbed on the 24th, and if indeed this specific orbital plane at 90-degree angle to that of USA 290 is aimed for, the launch time will shift ~13 minutes earlier each day.

USA 290 at the time was widely believed to be a new generation electro-optical reconnaissance (IMINT) satellite, a follow-on on the KH-11 ENHANCED CRYSTAL program. That it was launched, as NROL-91 will be, in a non-sun-synchronous orbit is odd though, for an optical reconnaissance satellite. 

One really wonders why the sun-synchronous polar orbit typical for such missions (and typical for earlier generation KH-11 EVOLVED ADVANCED CRYSTAL missions) was dropped in favour of this new 73.6 degree orbital plane. What is the advantage of this new orbital configuration? Or are USA 290 and NROL-91 perhaps not electro-optical systems, but something else?

Wednesday, 7 September 2022

Kosmos 2558 keeping its orbit close to USA 326 [UPDATED]

 [updated 9 Sept 2022 20:00 UTC]

In a series of previous blogposts (here, here and here) I wrote about a cat-and-mouse game going on in space, where the recently launched Russian satellite Kosmos 2558 (2022-089A) is stalking the US spy satellite USA 326 (2022-009A).

That game of cat-and-mouse is still ongoing. Over the past week, Kosmos 2558 has been making adjustments to its orbital inclination (see the diagram above). 

At first glance, you would say that it is apparently moving its orbit away from USA 326, as it is increasing the difference in orbital inclination.

But that is deceptive. The difference in orbital inclination between the two objects is actually very small (currently 0.2 degrees), and so is the difference in RAAN (currently 0.26 degrees). The two objects basically share the same orbital plane.

So why the adjustments in orbital inclination? If you look at the diagram below, which depicts the effects of the orbital inclination adjustments on the precession of the RAAN (i.e. the drift of the node of the orbit), you will note that the effect is that the RAAN precession starts to more closely match that of USA 326.

In other words:  the adjustment is actually in order to get the precession of the two orbital planes synchronised, i.e. to make sure the orbital planes do not drift too far apart. This ensures that the two objects will continue to share virtually the same orbital plane.


Click diagrams to enlarge 


Because Kosmos 2558, while sharing the same orbital plane as USA 326, is orbiting at a slightly lower orbital altitude than USA 326 (on average some 60 km lower), its orbital inclination needs to be slightly different from that of USA 326 in order to maintain a similar RAAN precession: the rate of RAAN precession depends on both the inclination and orbital altitude.

The fact that it is making adjustments to synchronize its rate of RAAN precession with that of USA 326, again makes clear that the launch of Kosmos 2558 into the orbital plane of USA 326 is no coincidence.

The image below shows how closely the orbital planes match: the main difference is a relatively small difference in altitude. This results in slightly different orbital periods for both satellites, and as a result Kosmos 2558 is 'taking over' USA 326 every 5 days, resulting in flyby's at distances of 60 to 80 km each 5 days.


click image to enlarge


UPDATE 9 Sept 2022 20:00 UTC:

Kosmos 2558 made an orbit raising manoeuvre on 8 September 2022 around 11:10 UTC, raising apogee by 5.5 km and perigee by 1 km. It also adjusted its orbital inclination again, to get the RAAN precession closer to that of USA 329:


click diagram to enlarge

click diagram to enlarge

Sunday, 14 August 2022

Will China's second 'Space Plane' land on August 15? (UPDATE: No, it didn't)

Over the past 10 days I have been following the second test flight of China's "Experimental Test Spacecraft" (2022-093A), a.k.a. it's "Space Plane". See also an earlier post.

The 'Space Plane' has been on orbit now for almost 10 days. That is already clearly longer than the first 2-day test flight from 2020. We have no idea how long they intend to fly it this time. It may be two weeks, maybe months, maybe more. We don't know, and will have to see.

However, if it would land within days from now, then my bet is it will be on August 15 near 7:00 UTC.

[update: it didn't land. As of early August 16, it was still on orbit]

On that date on that particular pass, if the spacecraft does meanwhile not manoeuver, the 'Space Plane' groundtrack will cross right over the landing strip near Lop Nor where the previous test flight landed. The maps below show the track leading to it, and how the track actually passes over the landing strip (the triangular structure in Copernicus Sentinel image) near 6:57 UTC on August 15:

click map to enlarge

click map to enlarge


UPDATE 16 August: it did not land on August 15. 

NOTE: this post originally also featured a plot of the RAAN evolution of the spacecraft, with what appeared to be a 'wobble', suggesting small corrective manoeuvers.

I deleted the diagram and accompanying text because it turned out that a weird bug in my spreadsheet (Excel) caused it (!). I am still not sure what happened there. Reloading the dataset and then creating a new diagram had the wobbles disappear. Even though it was the same dataset in the same columns of the spreadsheet. 

Thanks to Cees Bassa for noting something was off with the original plot.

Saturday, 6 August 2022

The flyby of USA 326 by Kosmos 2558 on August 4: a post-analysis

click image to enlarge

In a previous post I discussed the launch of Kosmos 2558 (2022-089A), a Russian military satellite which was launched from Plesetsk on August 1, 2022. 

As I pointed out, it was inserted into the same orbital plane as the American classified military satellite USA 326 (2022-009A, an electro-optical reconnaissance satellite launched in February 2022), at an orbital altitude only a few tens of kilometers below it. 

And that was probably no coincidence: Kosmos 25578 is likely an 'inspector' satellite meant to surreptitiously check out USA 326.


click image to enlarge


The two satellites had a relatively close flyby on August 4. I did a post-encounter analysis based on orbits from before and after the flyby, to assess the time and the distance of the flyby.

I find that the close flyby happened near 14:16:27 UTC (August 4, 2022), give or take a few seconds, at a nominal distance of ~67 km. Most of that distance (about 64 km) is in altitude. 

The flyby happened in daylight near 42.3 N, 25.9 W, over the mid-Atlantic, while both objects were southbound. USA 326 was at an altitude of about 518 km at that time, and Kosdmos 2558 at an altitude of about 453km.

Below is an animation of the flyby, as seen from two viewpoints (first lateral, than oblique):


~67 km is a clear safe distance and therefore no cause for worry (although it worried some generals in the Pentagon perhaps), but nevertheless close enough to make it interesting. I strongly suspect that Kosmos 2558 was imaging USA 326 at the time, in an attempt to gather information on the character of the satellite.

The diagram below gives the distance with time between Kosmos 2558 and USA 326 around the time of the approach.

click diagram to enlarge

It will be interesting to follow the two objects and see whether a new flyby happens at some point. In a previous similar case in early 2020, another Kosmos satellite, Kosmos 2542, was sent to check out the US military satellite USA 245, and released a second satellite, kosmos 2543, that chased the US satellite for a while.


Added comment:

Fred Jansen made a pertinent remark: from launch to operational in a mere 3 days would be awfully fast.
Another issue, brought up by Allan Thomson, is that the Sun-Kosmos 2558-USA 326 angle was quite low during this encounter, which is  not ideal.

However, as the two objecst share the same orbital plane, these encounters repeat at intervals: so even if it was not ready and fully operational yet during this approach, there will be other opportunities in the future. It will be interesting to see whether Kosmos 2558 will raise its orbit at some point, or will do other manoeuvres to keep the precession of its RAAN in line with that of USA 326.

(Note: the orbital elements for USA 326 used in this analysis are based on optical tracking data by an international group of  Independent Space Observers, including myself, Cees Bassa and Russel Eberst)

Observing China's Re-usable Test Vehicle (or "space plane")


frame stack. Click to enlarge

On August 4 2022 near 16:00 UTC, China launched a CZ-2F from Jiuquan carrying a "re-usable experimental spacecraft". It is the second orbital test flight of the Chinese 'space plane', China's answer to the X-37B, following an earlier orbital flight in September 2020 (see my 2020 blog post) . In 2020, the craft returned and landed on a landing strip near Lop Nur after two days on orbit.

Above is a frame stack of 76 frames showing the spacecraft and the CZ-2F upper stage from the launch in the evening of 5 August 2022 near 20:10 UTC. The frames are from the video below which I shot from Leiden, the Netherlands, with a WATEC 902H2 Supreme + Samyang 1.4/35 mm lens, in deep twilight (sun at only -6 degrees elevation):



The re-usable experimental spacecraft was launched into a 346 x 593 km, 50-degree inclined orbit. The orbital inclination is similar to the September 2020 test launch: the orbital altitude is however different this time. The 2020 test flight was in a 331 x 347 km orbit: the current flight is in a more eccentric orbit with higher apogee altitude (at almost 600 km, or 250 km higher than in 2020).

click image to enlarge

Eight objects (2022-093A to H) have been catalogued from this launch: the reusable test vehicle itself, the CZ-2F upper stage, four pieces of CZ-2F debris, and two additional objects of unknown character, objects G and H. The latter might be secondary payloads. They could perhaps be test targets to retrieve, or 'inspector' satellites to check the outside of the spacecraft. We'll see what happens. They are apparently small as my camera yesterday only registered the test vehicle and the CZ-2F upper stage.

On the previous flight, multiple objects were catalogued as well: apart from the test vehicle itself and the CZ-2F upper stage, there were - just like now- four pieces of CZ-2F debris catalogued. In addition an object was ejected from the test vehicle some 3.5 hours before the latter landed (speculation at the time was that it might have been an inspector satellite to inspect the outside condition of the spaceplane before the landing). That object reentered in December last year.

For the current test flight, the currently catalogued 8 objects, 2022-093A to 2022-093H, have varying apogee altitudes. The H-object has a notably more circular orbit than the other objects:

click diagram to enlarge

It will be interesting to see how long the orbiter will stay on orbit this time, and whether it will manoeuvre (it did not during the previous test flight). When it lands, we expect that to be at the same landing site as in 2020, a remote landing strip near Lop Nor (see the end of this 2020 post).


[added 7 Aug 2022]

Below is footage of another pass, taken in the evening of 6 August 2022. First object to come into view is the CZ-2F upper stage from the launch; then follows the 'space plane' (plus an airliner).

Wednesday, 3 August 2022

A stalker and its prey (Kosmos 2558 and USA 326)


In my previous post I discussed the newly launched Russian military satellite Kosmos 2558 (2022-089A), that was launched on August 1 into the orbital plane of the US military IMINT satellite USA 326 (2022-009A). There are indications that it is an 'inspector' satellite that is going to take a detailed look at USA 326.

Last night I observed them both, passing about half an hour after each other. Over the enxt 24 hrs Kosmos 2558 will approach USA 326, to a distance of ~75 km on August 4 ~14:47 UTC, if they do not manouvre in the mean time.

Above are framestacks from the captures (in the image with USA 326, a flaring Starlink, Starlink-1349, is also visible, in the lower left corner).

Below is the video footage. It was taken with a WATEC 902H2 Supreme with a Pentax 1.2/50 mm lens at 25 fps.

It will be interesting to follow this Cold war cat-and-mouse game above our heads over the coming days and weeks....



Tuesday, 2 August 2022

Kosmos 2558, a Russian inspector satellite targetting the US IMINT satellite USA 326?


click image to enlarge

On August 1, 2022, at 20:25 UTC, Russia launched a Soyuz 2.1v carrying a military satellite from Plesetsk into a Polar orbit. It has since been catalogued under nr 53323 (COSPAR ID is 2022-089A). It will probably receive the designation Kosmos 2558

Directly after launch it was in a 435 x 452 km, 97.25 degree inclined orbit. The Volga upper stage was catalogued in a 284 x 425 km orbit.

Before the launch, there was a rumour that this was another 'inspector' satellite - a snooping satellite meant to covertly inspect another satellite. After some speculation about the potential target arose, I pointed out that the middle of the launch window as indicated by NOTAM's for the launch, 20:30 UTC, was close to the moment that the orbital plane of the classified US electro-optical IMINT satellite USA 326 (2022-009A) passed over Plesetsk, at 20:25 UTC

And sure enough, it did indeed launch at 20:25 UTC, into the orbital plane of USA 326. And as it turned out, into an orbital altitude that is close as well.

The apparent target, USA 326, was launched in February and is widely believed to be a new generation electro-optical IMINT satellite. It moves in a 97.4 degree inclined, 489 x 518 km sun-synchronous polar orbit. 

The RAAN of the newly launched Kosmos 2558 matches the RAAN of USA 326 closely, with a difference of only 0.04 degree (changing by about 0.01 degree/day). The close correspondance of the two orbital planes can be seen in the diagram above. The orbital altitude of Kosmos 2558 is about 60 km lower than that of USA 326, but that might change if any post-launch manoeuvres are done the coming days and weeks.

With the current orbit, Kosmos 2558 will make a relatively close approach to USA 236 at August 4 near 14:47 UTC. The approach distance is ~75 km, almost all of that (73 km) is in altitude.

 [EDIT: a post-encounter analysis on 6 Aug 2022 based on orbits closer to the approach moment gives 4 August ~14:16:27 UTC for the approach, and a nominal distance of 67 km, most of this in altitude]

In early 2020, Russia did something similar with Kosmos 2542/2543, directing it towards the KH-11 electro-optical reconnaissance satellite USA 245.

It will be interesting to follow both satellites the coming weeks, to see what happens.

Thursday, 28 July 2022

CZ-5B rocket stage 2022-085B: reentry forecasts

 (this post is periodically updated when new tracking data become available and have been analyzed)

last updated 30 July 19:05 UT   

My latest forecast is: 30 July, 17:10 UTC +- 15m

The latest CSpOC forecast was:  30 July, 16:49 UTC +- 10m 

The FINAL CSpOC TIP is 16:51 UTC +- 1m, near 3.4 N, 113 E

A possible reentry observation has been made from Kuching (Sarawak, Borneo) near 16:50 UTC 

Click diagram to enlarge


On 24 July 2022, China launched a CZ-5B rocket carrying the Wentian module to the Chinese Space Station. The huge CZ-5B core stage, 2022-085B, with a dry mass of 18 tons and a length of 33 meter, is now set for an uncontrolled reentry on July 30.

The diagram above shows the evolution of apogee and perigee altitudes so far.

I am running reentry models in the General Mission Analysis Tool (GMAT) for the CZ-5B stage, that currently point to reentry in the second half of July 30 UTC. At this point in time it is still too early to pinpoint a more precise time or location - and for this reason I do not give geographic coordinates for the nominal reentry point yet.

The map below shows the current risk area, based on the latest forecast and its uncertainty window. Within the uncertainty window, the rocket stage can come down anywhere on the blue line in the map. The yellow circle is the nominal reentry position, i.e. the center of the uncertainty interval, but not necessarily the most likely location.


Current risk area. Click map to enlarge

Movement of the spacecraft is from west to east = left to right on the map. Cities between 41.5 N and 41.5 S with 1 million or more inhabitants are shown as yellow dots.

Below is a diagram of the evolution of the reentry forecast so far. Below the diagram is the same data in tabular form, with the most recent forecast at the bottom of the table.

- My latest GMAT based forecast (black dots) is: 30 July, 17:10 UTC +- 15 m

- The last pre-reentry CSpOC TIP forecast (red dots) is: 30 July, 16:49 UTC +- 10 m

- The FINAL CSpOC TIP is 16:51 UTC +- 1 m, near 3.4 N, 113 E

The latter time, with its 1 minute uncertainty, and position are likely based on an infra-red detection of the reentry fireball by a SBIRS Early warning satellite. So it seems my last forecast was about 20 minutes off. It reentered more or less at the start of my uncertainty window.

Below is a map with the final revolution and actual reentry location:


click map to enlarge

Each dot is a prediction based on a new orbit release. On the x-axis is the date/time (in decimal days) of the orbit on which the forecast is based. On the y-axis is the predicted reentry time/date resulting from a GMAT model run using  this orbit. These too are given in  decimal days (e.g., "30.5" = "30 July, 12:00 UTC". Note: for dates beyond July 31, "July 32.0" means "August 1, 00:00 UTC" etc.). 

Error bars show the uncertainty in the prediction. Note how the uncertainty window become smaller once we get closer to the reentry.

The black dots are the results of my GMAT model runs. The red dots are predictions by CSpOC, the US Military tracking organization (and "the" authoritive source of orbital tracking data), given for comparison.

click diagrams to enlarge

My reentry modelling in GMAT uses the MSISE90 model atmosphere, current, predicted and past spaceweather, a dry mass of 18000 kg and a drag surface of 62% of the maximum value, which is the best estimate for the average drag surface of a tumbling rocket stage of these dimensions. The depicted uncertainty window is a fixed 20% of the timespan between orbit epoch and the reentry time forecast resulting from the orbit.


GMAT model forecasts:


 25-07 11:52:33    31-07 08:28  +-  28.1 h
 25-07 13:01:55    31-07 02:51  +-  26.8 h
 25-07 14:30:57    31-07 02:42  +-  26.4 h
 25-07 17:29:00    31-07 02:45  +-  25.9 h
 25-07 19:29:01    31-07 02:08  +-  25.3 h
 26-07 03:04:47    31-07 02:39  +-  23.9 h
 26-07 11:16:28    31-07 03:40  +-  22.5 h
 26-07 13:11:03    31-07 02:22  +-  21.8 h
 26-07 15:43:05    31-07 02:34  +-  21.4 h
 26-07 18:40:46    31-07 02:44  +-  20.8 h
 26-07 19:12:28    31-07 01:04  +-  20.4 h
 27-07 14:41:30    30-07 21:29  +-  15.8 h
 27-07 15:55:00    30-07 20:57  +-  15.4 h
 27-07 17:18:31    30-07 21:01  +-  15.1 h 
 27-07 18:20:32    30-07 23:39  +-  15.5 h
 28-07 17:05:39    30-07 23:46  +-  10.9 h
 29-07 01:18:22    30-07 21:36  +-   8.9 h
 29-07 08:55:31    30-07 20:12  +-   7.1 h  
 29-07 13:03:52    30-07 19:20  +-   6.1 h   
 29-07 16:34:29    30-07 18:58  +-   5.3 h  
 29-07 18:00:07    30-07 19:00  +-   5.0 h  
 30-07 01:31:37    30-07 20:06  +-   3.7 h 
 30-07 08:22:22    30-07 17:50  +-   1.9 h  
 30-07 09:54:18    30-07 17:29  +-   1.5 h  
 30-07 12:28:44    30-07 17:28  +-   1.0 h 
 30-07 12:58:01    30-07 17:30  +-    54 m  
 30-07 14:17:27    30-07 17:20  +-    37 m   33 N 126 W  
 30-07 15:48:42    30-07 17:09  +-    16 m   40 N 178 E
 30-07 15:57:24    30-07 17:10  +-    15 m   41 N 173 W  latest


UPDATE 30 July 17:15 UT:

Footage purportedly shot today from Kuching (Sarawak, Borneo) appears to show the reentry of 2022-085B. It would place reentry near ~16:50 UTC. The footage is here, in a tweet by Nazri Suleiman.
I say 'purported' because for the moment the footage has not yet been verified. But it seems likely it is the reentry indeed.


UPDATE 30 July 19:05 UT:

CSpOC gives a final TIP of 16:51 +- 1m UTC near 3.4 N, 113 E, which matches the Kuching sightings well (multiple video's from the Kuching region have since turned up on social media, so it is now quite certain that this was the reentry).

The map below gives the final orbital revolution and location of reentry over Borneo.


click map to enlarge


Other forecast sources:

CSpOC  (https://www.space-track.org/)

Aerospace Corporation  (https://aerospace.org/reentries/cz-5b-rb-id-53240)

Josep Remis  (https://twitter.com/jremis)

ESA  (https://reentry.esoc.esa.int/reentry) 

EU-SST (https://twitter.com/EU_SST) 


Added note on 'Live' satellite tracking websites

BEWARE: contrary to what many people think, purported 'Live' satellite tracking websites such as n2yo.com are NOT showing you satellite locations based on 'live' tracking data!

In reality, they show predictions based on older orbital element sets, that can be hours old actually.

This can be deceptive. They sometimes happily show an object apparently still "on orbit" after it in reality already reentered!