RPO Galore: the complex proximity operations of Kosmos 2581, Kosmos 2582, Kosmos 2583 and 'Object F'

click image to enlarge

Some 590 km above our heads, a complex series of multiple Rendezvous and Proximity Manoevers (RPO) by multiple Russian military spacecraft has been going on the past months, weeks and days.

On 5 February 2025, Russia launched three satellites from Plesetsk, into a 82 degree inclined orbit: Kosmos 2581, Kosmos 2582 and Kosmos 2583 (2025-026A, B and C). Kosmos 2581 was initially placed in a 595 x 578 km orbit; Kosmos 2582 in a 597 x 576 km orbit; and Kosmos 2583 in a 597 x 580 km orbit.

The diagram below sums up what has unfolded over the past few months: a complex series of manoeuvers and approaches to each other.

Click diagram to enlarge

 

About two weeks after the launch, both Kosmos 2581 and Kosmos 2582 were manoeuvered to a slightly higher orbit: Kosmos 2582 did so on 15 February and Kosmos 2581 on 19 February. 

On 24 February, Kosmos 2582 manoeuvered again, this time slightly lowering its orbit to the same orbital altitude as Kosmos 2581, for the initiation of first of a long series of complex proximity manoeuvers. They made a very close approach (1 km or less) on 24 February around 21:44 UTC. They stayed in each others close vicinity for the next three months, manoeuvering to and fro, with Kosmos 2582 doing the manoeuvering and Kosmos 2581 acting as the target..

Meanwhile, on 18 March 2025, the third satellite from the launch, Kosmos 2583, surprised by releasing a fourth object, 'Object F' (2025-026F). This object appears to be passive (i.e. it does not appear to be manoeuvering), but starting in April, Kosmos 2583 has subsequently been doing RPO manoeuvers with it, manoeuvering to and from it repeatedly, untill late May, so perhaps it is not merely debris. 

On 26 May, Kosmos 2583 manoeuvered away from 'Object F' to a higher orbit. It subsequently made a series of manoeuvers that made it closely approach Kosmos 2581 to a few hundred meters or less on June 10 near 9:42 UTC. It next stayed in the close vicinity of Kosmos 2581, approaching it again very closely in the days around June 19.

While Kosmos 2582 meanwhile had stayed in the wider vicinity of the other two, following them at a  distance of several hundreds of kilometers, it manoeuvered on June 23 in order to get close, within kilometers, to the by then close pair of Kosmos 2581 and Kosmos 2583. As a result, all three objects were now orbiting closely together.

 

click image to enlarge

The framestack above is from video footage I shot from Leiden, the Netherlands a few nights later during a near-zenith pass in twilight on 28 June 2025, when the three objects were still in close vicinity, albeit less close than the days before (during the days before, they were so close that I generally could not resolve them). Kosmos 2581, 2582 and 2583 are all visible in the framestack, the latter however being very faint.  

Kosmos 2581 and Kosmos 2582 were at about 1.2 km from each other at the time of observation. Kosmos 2583 was at about 3.6 km from Kosmos 2581.

Below is the actual video footage the framestack was derived from: the two brighter objects are Kosmos 2581 and 2582 (Kosmos 2581 leading), and just in front of them is Kosmos 2583, barely visible (look closely at full screen during the first 4 seconds of visibility). It was shot from my home in Leiden, the Netherlands, with a WATEC 902H2 Supreme and Samyang 1.2/85 mm lens.

'Object F' meanwhile, has drifted to quite a distance from the other three objects. Below is a framestack showing it, from video observations obtained on 17 June 2025: it was faint and might show some brightness variation.

Click image to enlarge

 

This is one of the most complex RPO exercises Russia has been conducting in LEO in decades. The RPO appears to be ongoing, and it will be interesting to follow it: for example, will we see that at one point 'Object F' is becomes the subject of an RPO again or not?

 

Post scriptum: more on another recent event with another Russian satellite, Kosmos 2558, releasing an object in another blogpost from today. 

Kosmos 2558 released an object on orbit on June 26 [UPDATED]

Object C (click image to enlarge)

 

Kosmos 2558 (2022-089A, cat nr. 53323) is a Russian military satellite that was launched from Plesetsk three years ago, on 1 August 2022. It was launched into the orbital plane of an American ADVANCED CRYSTAL spy satellite, USA 326. It is therefore believed to be a 'Nivelir' type 'inspection satellite' (see also this earlier discussion of several of such missions, and Bart Hendrickx' Space Review article on the Nivelir program  here).

As I recently wrote, there have now been four of these missions in a five-year timespan. Apart from Kosmos 2558 discussed here, these are: Kosmos 2542/2543 launched in the orbital plane of USA 245 in 2020;  Kosmos 2576 placed in the orbital plane of USA 314 in 2024 (see this earlier blogpost); and very recently, Kosmos 2588 placed in the orbital plane of USA 338 (see this earlier blogpost). 

With the exception of Kosmos 2542/2543, which have been deorbitted, all three remaining missions are still dedicatedly shadowing their American targets, keeping their orbital altitude and inclination difference such that the rate of RAAN (node) precession matches that of their target. This ensures that the orbital planes do not drift apart.

While mostly seen as 'inspection missions', I have repeatedly voiced a concern that these missions might be the positioning of 'dormant' on-orbit Anti-Satellite (ASAT) weapons. To me, the long, ongoing shadowing of what are some of the most prized US military space assets, their KH-11 Advanced Enhanced Crystal high-resolution optical IMINT satellites, is odd for 'just' an inspection mission. What is there still left to inspect after 3+ years? The satellites make only periodic close approaches (every few days) so monitoring of attitude (pointing) or radio signals is not an explanation.

Understandibly, the 'stalking' behaviour of these Kosmos satellites on their satellites makes the US military nervous. And now they have yet another reason to get even more nervous: on 26 June 2025 near 12:03 UTC (according to my analysis), Kosmos 2558 released  a second object, currently designated as 'Object C' (2022-089C, cat nr. 64627). 

The release is actually visible in the orbital elements for kosmos 2558, as a sudden slight lowering of the orbit:
 

Click diagram to enlarge

 

This is the third time we see this kind of 'Matrushka Doll' behaviour from Russian military satellites in five years time. 

Shortly after reaching orbit in 2020, Kosmos 2542 released a sub-satellite too, Kosmos 2543, which next in turn fired what is interpreted as a projectile, 'object E' (the latter was widely seen as an ASAT technology test at the time). 

In addition, more recently, Kosmos 2583 released an object, 'Object F' (2025-026F), on 18 March this year, as part of a complex series of RPO's (Rendezvous- and Proximity Operations) between Kosmos 2581, Kosmos 2582, Kosmos 2583 and said 'Object F'. I will publish a separate blogpost on these later [edit: separate post now available here].

In 2020 and more recently with Kosmos 2583 and 'Object F', this spawning of other objects happened within weeks after the launch of the parent satellite. But this time with Kosmos 2558 and 'Object C', the release of a second object happened almost three years after launch.

I observed Kosmos 2558 and the newly released 'Object C' last night. 'Object C' reached magnitude +8. The images below are 1-second frame stacks from video observations I made from Leiden, the Netherlands, on the night of 28-29 June 2025, two-and-a-half days after 'Object C' was released. At the time of observation, 'Object C' was some 143 km distant from Kosmos 2558, passing the camera FOV some 16-seconds after it. The first framestack shows 'Object C'; the second shows Kosmos 2558.

 

Object C (click image to enlarge)

 

Kosmos 2558 (click image to enlarge)

Below is the video footage of the pass in question. The first to pass through the FOV is Kosmos 2558 as a bright object: then, some 16 seconds later, 'Object C' passes through the FOV as a fainter object. The footage was shot from Leiden, the Netherlands, with a WATEC 902H2 Supreme camera and Samyang 1.2/85 mm lens.

 

 

It will be interesting to see whether any manoeuvering between the two objects is happening over the coming weeks.

 

UPDATE 4 July 2025:

Since release, Object C has been manouevering with respect to Kosmos 2558. While initially manouevering back to Kosmos 2558, it lowered its orbit significantly (by 15 km) on July 3 near 18:42 UTC. See diagram below.

Click diagram to enlarge

The reentry of the Chinese Zhuque-2E upper stage 2025-103G over Kazachstan on 5 June 2025

still from one of the fireball movies posted on Twitter by @Buggy__Bugler

 

In the evening of 5 June 2025 around 22h local time (17h UTC), a slow profusely fragmenting fireball was seen and filmed from several cities in Kazachstan, including Astana, and Bishkek in neighbouring Kirgistan. It had all the well-known characteristics of a satellite or rocket stage reentry. Indeed, as it turns out, this was a rocket stage reentry: the reentry of the upper stage of a Chinese Zhuque-2E (ZQ-2E) rocket, 2025-103G, from a multiple satellite launch on May 17.

Unfortunately, some Russian and Ukranian language twitter accounts started to disseminate the footage with the wildly wrong suggestion that this was a failing Russian Oreshnik IRBM breaking up. This misinformation next proliferated very quickly via various social media, and later also traditional media (e.g. Newsweek). This while it is not a Russian Oreshnik missile at all, as already mentioned.

I was alerted to the event somewhat later that evening when several of my social media followers tagged me and asked me for my opinion. It didn't take me long to identify the event as a space-launch related reentry rather than a Russian missile. Indeed, the Kazachstan MoD had meanwhile also deemed it a space debris reentry, per various news outlets.

The object in question was 2025-103G (cat. nr. 64054), the Zhuque-2E (ZQ-2E) upper stage from a Chinese satellite launch on 17 May 2025 from Dongfeng (Jiuquan). The upper stage from this launch was left in an in initially 600 x 175 km, 96.1 degree inclined orbit.

The CsPOC TIP for this object's reentry available at that time (it was updated later), had forecast reentry at 5 June 2025, 15:40 UTC with an uncertainty of  ± 3 hours. The Kazachstan event (~17h UTC) hence was within the reentry window. When I checked the trajectory over this full window, it showed that the object would make a south-to-north pass over eastern Kazachstan around 17:10 UTC, very close in time to the Kazachstan event (which was reportedly around 10 pm local Astana time = around 17 hr UTC). Direction of movement in the various videos of the event matched well.

Later, CSpOC published a final TIP placing the reentry at 5 June 2025 17:08 UTC  ± 1 min, near 36.6 N, 73.5 E. Given the 1 minute accuracy, this is likely based on a DoD satellite observation of the reentry fireball. The TIP position is just south of Kazachstan, but a reentry is a process of several minutes duration. Moving south-to-north, the fireball created by the fragmenting space debris would move northwards, over eastern Kazachstan, in the minutes directly after this time mark. In other words, this final TIP matches the event quite well.

Below is the trajectory over the final revolution of the ZQ-2E upper stage, based on the last available TLE (epoch 25156.48638369) which dates from ~5 hours before the reentry:

 

Click map to enlarge

I next ran a reentry model with our Delft Technical University open source Astrodynamics package Tudat. The ZQ-2E upper stage has a dry mass of approximately 5000 kg and measures 12 x 3.4 meter. Using 60% of the maximum drag area for that dimension, a value usually representing the average drag surface of a tumbling (and hence showing a variable drag surface) elongated rocket stage well, the Tudat model predicts reentry near 17:03 UTC ± 1.1 hr (remember, this is based on a 5 hour old orbit), the nominal value being well in line with the Kazachstan event and nominally within 5 minutes of the CSpOC final TIP.

Next I ran the model again adjusting the drag area slightly, via trial-and-error, such that the model would conform to the estimated start of visibility of the reentry fireball, at just below  ~100 km altitude, at the time/location of the CSpOC TIP (17:08 UTC). 

I get a reasonable match when I reduce the drag area to about 58% of the maximum drag area. Below is a map showing the resulting estimated reentry trajectory (movement is from south to north):

click map to enlarge

When I use this Tudat-estimated reentry trajectory to generate a sky track for Astana, Kazachstan, I get this approximate sky trajectory (movement is from left to right, i.e. south to north, low through the west):

Click map to enlarge

This conforms quite well to some of the video footage of the reentry (several of which show the reentry fireball pass the waxing moon), e.g.:

 

still from one of the movies posted on Twitter by @Buggy__Bugler

The predicted sky track for Astana of course depends on how accurate our Tudat-modelled atmospheric altitudes of the reentering rocket stage are. If they in reality are a bit lower than we modelled, the trajectory will be located slightly lower in the sky (and vice versa, slightly higher if the altitudes are in reality a bit higher). It is very clear however that the general direction and location of the trajectory in the sky matches well with what was seen and filmed.

As usual, I feel some frustration about the general absence of information on camera locations and time of the footage regarding the imagery of this event distributed via various social networks. Those data are important but almost never included. These matches of observations with reentry data would get so much easier if people posting footage would include the geographic location and the time. So please people: next time you post something like this, include these important data.

This event once again also showed the failure of AI as a reliable source of information for answering questions regarding events like this (we earlier saw that with the Kosmos 482 Descent Craft reentry too). Twitter's AI "Grok" generated some profound nonsense (i.e., misinformation) when people asked it to identify the character of the event, likely partly as a result of the large amount of disinformation already doing the rounds on social media about this event.

Raiders of the Lost Venus Probe: a post-mortem of an interesting reentry and the confusion it left

On 10 May 2025, an unusual object, the Kosmos 482 Descent Craft, had an uncontrolled reentry (see this earlier post).

With my TU Delft colleague Dominic Dirkx, I have written a 'post mortem' for this reentry for The Space Review of 27 May 2025, titled:

 "Raiders of the Lost Venus Probe: a post-mortem of an interesting reentry and the confusion it left"

It can be read here.

(the Tudat script we used for our reentry analysis can be downloaded here. Tudat itself can be downloaded here). 

Kosmos 2588 has been placed in the same orbital plane as the US spy satellite USA 338: another RPO?

click image to enlarge

 

Russia launched a new military satellite from Plesetsk today (23 May 2025), Kosmos 2588 (cat nr. 64095, COSPAR 2025-109A). It was placed in a 73-degree inclined, approximately 464 x 481 km orbit.

As first noted by Bart Hendrickx, the orbital plane is very close to that of a US military optical reconnaissance satellite, USA 338 (2022-117A). This can be seen in the diagram above. 

The difference in RAAN is only 0.11 degrees, the difference in inclination is a mere 0.6 degrees. Kosmos 2588 orbits just above USA 338. They can come to within 100 km of each other in this orbital configuration.

This is the fourth time in the last five years that Russia has placed a military satellite in the same orbital plane as and very close in orbital altitude to that of a US military optical reconnaissance satellite. 

The first time was in 2020 when they placed Kosmos 2542/2543 in the orbital plane of USA 245. That had the appearance of an 'inspector satellite' mission (although Kosmos 2543 later fired a projectile). The second time was in 2022 when Kosmos 2558 was placed in the orbital plane of USA 326. The third time was in 2024, when Kosmos 2576 was placed in the orbital plane of USA 314 (see my earlier blogpost here). 

The latter two occasions were different from the first, in that the Russian satellites in question stayed co-planar with the US satellites, rather than paying a relatively brief visit as Kosmos 2542/2543 had done. Rather than being inspector satellites, we might perhaps be seeing a counterspace capacity (a sleeping co-orbital ASAT capacity) being positioned in the latter two cases.

Which makes the current fourth instance highly interesting: the plot thickens. It will be interesting to see whether they keep this one co-planar as well.

It is possible that, as was the case with the launch of Kosmos 2576 a year ago, multiple payloads have been put in space. So far (less than a day after launch) only one has been catalogued.

We are seeing more and more of these RPO activities (in LEO as well as GEO) lately. Things in space are clearly getting more confrontational and passive-aggresive. A very worrying trend.

The tumbling behaviour of the mysterious Kosmos 2553 satellite

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

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

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

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

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

 

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

 

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

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

Click diagram to enlarge

 

 

Click diagram to enlarge

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

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

 

Click diagram to enlarge

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

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

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

Click diagram to enlarge

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

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

Kosmos 482 Descent Craft reentry forecasts [PERIODICALLY UPDATED]

Click diagram to enlarge

Last update: 11 May 2025 10:15 UTC 

 

(this post is being periodically updated with new reentry forecasts/postcasts)

 

* The last Tudat nominal forecast is reentry on 10 May 2025, 6:39 UTC ± 1.5 hr *

* The Tudat nominal aftercast is reentry on 10 May 2025, 6:40 UTC ± 1.5 hr *

 

 

 

In the second week of May 2025, an unusual object reentered. It concerns the Kosmos 482 Descent Craft (1972-023E, cat. nr. 6073).

This object is the lander module from a 1972 failed Soviet Venera mission to Venus. Because of a failure of the upper stage of the rocket that launched it, it got stuck in a very elliptical orbit around Earth in 1972, instead of going to Venus. 

 

I published an extensive discussion and analysis of this object and its history three years ago in The Space Review. The identification of this object as the lander module was initially suggested by Jonathan McDowell (see his brief interesting history here).

Recently declassified Russian historic documents unearthed by Anatoly Zak point out that after failure to get to a heliocentric orbit, the lander was deliberately separated from the main bus by the spacecraft operators. My analysis published in 2022 suggests that this happened in June 1972. The lander is encased in a semi-spherical shaped Titanium protective shell, a kind of rounded metal bucket so you will (see image below).

As this is a lander that was designed to survive passage through the Venus atmosphere, it is possible that it will survive reentry through the Earth atmosphere intact, and impact intact. It likely will be a hard impact: I doubt the parachute deployment system will still work after 53 years and with dead batteries. There are many uncertain factors in whether the lander will survive reentry though, including that this will be a long shallow reentry trajectory, and the age of the object.

 

 

Venera 7 lander mock-up. The Kosmos 482 Descent Craft is probably similar. Photo: NASA

 

The risks involved are not particularly high, but not zero: with a mass of just under 500 kg and 1-meter size, risks are somewhat similar to that of a meteorite impact. A Tudat reentry analysis to ground level suggests an impact speed (after atmospheric deceleration) of about  65-70 meter per second (~242 km/h), assuming the reentering lander did not break up or extensively ablate during reentry (see the diagram below: note the logarithmic scale of the x-axis). The kinetic energy at impact is similar to that of a 40-55 cm large (after ablation) meteorite fragment. As it will likely reach earth surface as only one single object, the risks involved are lower than for example those created by a Falcon 9 upper stage reentry, which showers multiple meter-sized objects over a large area (as we saw recently with the impact of Falcon 9 remains in Poland).

 

Click diagram to enlarge

 

The diagrams below shows the change in altitude of apogee and perigee over the past 1.5 years and the past 4 months: notably apogee has been coming down steadily, but in the past few months, perigee has started to come down too. Early May 10 around 00:35 UTC, the object was in a 166 x 120 km orbit, with apogee coming down by 70 km/day and perigee by 25 km/day (and these values increasing each day, see diagram below).

 

Click diagram to enlarge

 

Click diagrams to enlarge

 

The reentry is an uncontrolled reentry. Even close to reeentry, we cannot say with any degree of certainty when and where the Kosmos 482 Descent Craft exactly will reenter.

With an orbital inclination of 51.95 degrees [note: I initially erroneously stated 51.7 here], the reentry can occur  between latitude 52 N and 52 S.

Over the past months, together with my colleague Dominic Dirkx,  we have been developing a reentry model for this object in Tudat.

 

Tudat, the TU Delft Astrodynamics Toolbox is open source, multi-platform Astrodynamics software developed and maintained at the Aerospace faculty of Delft University of Technology (TU Delft) in the Netherlands (where I work). The Tudat script we use for our analysis is here, while the Tudat software itself is available here.

 

The Kosmos 482 Descent Craft is probably similar to the descent craft of Venera 8 (which was launched only a few days earlier in 1972). Literature values suggest that the object is about 1 meter in size and semi-spherical, with a mass of ~495 kg. 

 

Using our Tudat model and a 1-meter diameter, and the NRLMSISE00 model atmosphere with historic space weather data, we find that the orbital evolution of  the object from mid-1972 to early 2025 is actually best matched when we use a mass of 480 kg, 15 kg less than the literature value. All our forecast predictions are therefore done using a mass of 480 kg. 

 

For our forecasts we employ the NRLMSISE00 model atmosphere, and historic spaceweather data plus estimated future space weather (solar flux). Orbit updates for each run are sourced from the US Military tracking network CSpOC (so as a note: our forecasts are not based on our own tracking data. They are based on our own custom reentry model developed at Delft University of Technology, with external tracking data from CSpOC as input).

 

Click diagram to enlarge

The diagrams in top of this post and below (which I will periodically update) give the evolution of our reentry predictions, based on orbits issued for the object since November 2024. Over the past half year, the model has consistently pointed to reentry within a few days of 9-10 May 2025. 

 

The latest nominal forecasts currently center on early May 10, but are still fluctuating with each orbital update. Early May, there was a short-lived tendency in the model runs of a shift towards a later time of reentry (i.e. May 11 rather than May 10), as can be seen in the below diagrams and the table near the end of this post. But lately, the new forecast runs have been returning to nominally May 10. 

 

 

Click diagram to enlarge

 

Click diagram to enlarge

 

The brief shift towards a later date in the early May model runs was due to space weather forecasts underestimating future solar activity at that time. I had started to note this (when comparing earlier forecast solar flux values to actual solar flux values for the last days of April  and the first days of May) and already expected the nominal forecasts to return to May 10, as they now indeed have done.

 

This highlights the influence of uncertainties in estimated future solar activity on the forecasts. Future solar activity is not well predictable. Even the best reentry models will be off in their forecast if actual solar activity in the window between the moment of forecast and the moment of reentry develops differently than the predictions. Solar flux variations are an important driving factor of short-term variations in density and extent of the upper atmosphere. The latter determine how many drag the object experiences over its orbit, and with that how quick the orbit decays. Stronger solar activity will mean an earlier reentry, lower solar activity a later reentry.

 

Of course, at this point the uncertainty in the forecast is still +/- 1.5 hours. Yet, the uncertainty window has now decreased to the point that we can rule out certain parts of the world: Africa is safe. So is Japan, East Asia, and the USA.

 

The map below gives the trajectory of the object over the current uncertainty window of the Tudat reentry forecast (red dots are cities with over 1 million inhabitants, between latitude 52 N and 52 S). In our model the spacecraft could have reentered anywhere along the blue line:

 

Click map to enlarge

 

 

CSpOC, the US military tracking network, has started to provide TIP (Time of Impact Prediction) messages for the object since May 6. They are depicted as red circles in the diagram earlier in this post.

 

The last orbit update published by CSpOC has epoch 10 May 2025, 00:36 UTC, i.e. dates from about 6 hours before the time we think it actually reentered. There are later radar detections from Europe, per ESA, dating to as late as 6:04 UTC, but no orbit based on that has been published.

A roundup of current reentry forecasts from various sources (each running their own reentry model) compiled 10 May 15:30 UTC:

 

Tudat forecast:              10 May   06:39 ± 91  min UTC

Tudat postcast:              10 May   06:40 ± 91  min UTC

Aerospace Corp forecast:     10 May   06:29 ± 120 min UTC

RosCosmos postcast:          10 May   06:24 ± ?   min UTC

ESA postcast:                10 May   06:16 ± 22  min UTC

EU-SST forecast:             10 May   06:04 ± 20  min UTC

CSpOC TIP postcast:          10 May   05:32 ± 12  min UTC *

 

* this cannot be correct given that a positive radar detection from Germany at 6:04 UTC was reported by ESA.

 

note: forecast = issued before the reentry; postcast = issued after the reentry after re-analysis.

 

ESA reports that they had a positive radar detection of the spacecraft, still on-orbit, at 6:04 UTC while it was passing over Germany (presumably with the TIRA radar); and a negative detection one orbital revolution later, at 7:32 UTC. This implies reentry during the window 6:04 - 7:32 UTC. Five of the forecasts fall in that window: our Tudat forecast, and those by RosCosmos, ESA, the Aerospace Corporation, and also EU-SST when taking the error margins on the latter into account.

 

Roscosmos, the Russian Space Agency, on Telegram states reentry at "6:24 UTC" over the Indian Ocean. That is not too far (15 minutes) from our latest TUDAT model results. Three remarks: (1) this is not a reentry detection but likely another model result (just as the others), based on an earlier groundbased detection during a pass over presumably southern Russia. (2) It does not come with a stated uncertainty window: is that 10 minutes, 30 minutes, an hour? (3) It remains a question how serious one should take Russian State statements these days as sometimes pragmatic considerations (such as deliberate denial of responsibility or risk) are leading. 

 

While many news media seem to treat the RosCosmos announcement as 'authoritive' and the 'most accurate' or 'final' say on the matter, there is in reality no clear reason to do so. It is not clear at all whether the RosCosmos position is more accurate than the other model estimates, and how meaningful the stated positions and time are given the lack of error margin information.

A final accurate TIP from CSpOC has not yet appeared (and might not appear if they have no space-based detections of the reentry fireball). CSpOC sometimes, several hours to a day after a reentry, publishes a very accurate (with quoted +- 1 minute uncertainty) final TIP which Jonathan McDowell and I believe is not based on a reentry model, but on space-based (SBIRS satellite) detections of the reentry fireball, hence the accuracy. They have not issued such a TIP so far for this reentry, unfortunately. Note that their last issued TIP cannot be correct, given the reported positive radar detection of the spacecraft passing over Germany at 6:04 UTC.

 

This is how the nominal reentry points have been placed by various organisations, each based on their own modelling:

 

Click map to enlarge

 

It is clear that the assessments spread. Ignoring the clearly incorrect CSpOC TIP, the other models all suggest reentry over either southwest Asia or the Indian Ocean. My verdict is that the latter area is the most likely place.

 

Below is the evolution of the reentry forecast from our TU Delft Tudat model in tabular form, latest forecast at the bottom. Please take note of the uncertainty values listed in the last column!

 

The 'postcast' value is a re-run of the model after-the-fact based on the last published orbit and the actual rather than estimated space weather of May 10.

 

--------------------------------------------------------------------
TUDAT REENTRY FORECAST EVOLUTION for KOSMOS 482 Descent Craft
M. Langbroek & D. Dirkx, Delft University of Technology

Date/times in UTC

REFERENCE ORBIT    ORBIT EPOCH      REENTRY FORECAST   +/-   
----------------------------------------------------------------
15-11-2024 05:43   24320.23870400   05-05-2025 23:33   42.9 days   
01-12-2024 05:32   24336.23116452   08-05-2025 09:09   39.5 days   
15-12-2024 18:58   24350.79080401   07-05-2025 11:51   35.7 days   
01-01-2025 11:20   25001.47260254   09-05-2025 07:20   32.0 days   
15-01-2025 03:23   25015.14140884   10-05-2025 20:40   28.9 days   
02-02-2025 08:54   25033.37115746   13-05-2025 17:52   25.1 days   
15-02-2025 03:20   25046.13941015   11-05-2025 09:52   21.3 days   
01-03-2025 00:07   25060.00535989   10-05-2025 17:51   17.7 days   
15-03-2025 05:56   25074.24770046   10-05-2025 07:57   14.0 days   
30-03-2025 12:05   25089.50360681   09-05-2025 21:11   10.1 days   
13-04-2025 21:32   25103.89775709   09-05-2025 22:01    6.5 days   
20-04-2025 01:39   25110.06916305   09-05-2025 11:31    4.9 days   
22-04-2025 21:24   25112.89204293   09-05-2025 12:48    4.2 days   
23-04-2025 22:57   25113.95657237   09-05-2025 19:43    4.0 days   
27-04-2025 00:27   25117.01893077   10-05-2025 04:52    3.3 days   
28-04-2025 00:24   25118.01685903   10-05-2025 06:33    3.1 days   
28-04-2025 22:50   25118.95143786   10-05-2025 06:01    2.8 days   
01-05-2025 20:57   25121.87323063   10-05-2025 14:30    2.2 days   
02-05-2025 09:12   25122.38386703   11-05-2025 02:36    2.2 days   
02-05-2025 12:16   25122.51167762   11-05-2025 03:41    2.2 days   
02-05-2025 17:52   25122.74476620   11-05-2025 06:50    2.1 days   
03-05-2025 18:07   25123.75533175   10-05-2025 20:48    1.8 days   
03-05-2025 21:05   25123.87876286   10-05-2025 23:06    1.8 days   
04-05-2025 20:47   25124.86648285   10-05-2025 19:05    1.5 days   
05-05-2025 20:29   25125.85361170   10-05-2025 07:26    1.1 days   
06-05-2025 09:39   25126.40254557   10-05-2025 08:37    1.0 day
06-05-2025 21:26   25126.89335737   10-05-2025 07:51   20.6 hr
07-05-2025 21:00   25127.87559184   10-05-2025 07:34   14.6 hr
08-05-2025 11:31   25128.48053679   10-05-2025 07:24   11.0 hr
08-05-2025 13:13   25128.55136979   10-05-2025 07:34   10.6 hr
08-05-2025 19:13   25128.80083450   10-05-2025 07:54    9.2 hr
09-05-2025 12:37   25129.52575525   10-05-2025 06:23    4.4 hr
09-05-2025 14:12   25129.59226104   10-05-2025 06:30    4.1 hr
09-05-2025 15:43   25129.65543839   10-05-2025 06:35    3.7 hr
09-05-2025 19:55   25129.82989846   10-05-2025 06:34    2.7 hr
10-05-2025 00:35   25130.02495443   10-05-2025 06:39    1.5 hr

                               nominal location 35.7 S 126.5 E

POSTCAST:

10-05-2025 00:35   25130.02495443   10-05-2025 06:40    1.5 hr

                               nominal location 38.0 S 129.8 E

 

I will periodically update this table with new forecasts, more frequently so when the reentry dates comes nearer.

Here is footage I shot of the Kosmos 482 Descent Craft with my tracking camera in Leiden, in 2020:

An added note: about that parachute....

To muddy the waters further, a story is spreading that the parachute of the landing craft might already have deployed in space. This is based on telescopic imagery purportedly showing this.

I have strong doubts that the imagery in question shows any meaningful detail. The imagery has the same origin, and the same problems attached, as the imagery I discussed in 2022 in my Space Review article. I think the "detail" is the result of camera/telescope shake and atmospheric distortion.

 

UPDATE 28 May 2025:
With my colleague Dominic Dirkx, I wrote a 'post mortem' on the reentry for The Space Review that can be read here.

This post has been updated with new forecasts and additional background information several times

Observing FRAM-2, a commercial crewed Dragon mission in Polar orbit

Click image to enlarge

The image above is a stack of twelve 4-second exposures taken with a Canon EOS 80D and EF 2.8/24 mm lens, and shows the Crew Dragon FRAM-2 passing over the domes of the historic Leiden Observatory in the evening of 2 April 2025.

FRAM-2 is a commercial ("space tourist") mission using a SpaceX Crew Dragon launched into a 90.0-degree inclined Polar Orbit at approximately 430 km altitude. It is the highest inclination of any crewed space mission so far. The spacecraft has four astronauts onboard: Chun Wang, Jannicke Mikkelsen, Rabea Rogge and Eric Philips.

click image to enlarge

I observed the spacecraft on April 2 and 3, 2025. On April 2, on a 35-degree elevation evening twilight pass in the east, it reached magnitude +2.5 to +2.0. On April 3, on a high pass in the west, it was fainter, around +3.5 to +4.

Here is a single image from the series I shot on April 2 (4-second exposure at ISO 800):

Click image to enlarge

Below image is from the April 3 pass and shows both FRAM-2 and two Chinese satellites, as well as an unidentified object in a 49-50 degree orbit (possibly a Starlink or Starshield satellite). The "smudge" in the image is a lens reflection caused by the nearby moon:

 

Click image to enlarge

Here is a stack of 10 images from April 3:

Click image to enlarge

USA 498, the NROL-69 payload, found

click map to enlarge

On 24 March 2025 at 17:48 UTC, a Falcon 9 blasted off from Cape Canaveral launch pad 40 in Florida as NROL-69, carrying the classified USA 498 payload to orbit for the National Reconnaissance Office (NRO).

About two hours later, the launch caused a spectacle in the skies over Europe, as a bright spiral-shaped cloud formed in the sky, moving along the track of the Falcon 9 upper stage from the launch. This was due to the Falcon 9 upper stage venting excess fuel, in preparation for reentry over the Indian Ocean about half an hour later, following a deorbit burn over the northern Atlantic. 

The cloud of fuel droplets vented by the rocket stage was at an altitude of about 1000 km, where it was still in sunlight, causing it to shine brightly in the sky. The spiral pattern is due to the rocket stage spinning around is major axis, in order to stabilize the orientation of the stage in space. This is very typical for Falcon 9 upper stages and has been seen quite a few times now.

 

 

Prior to launch, Navigational Warnings seemed to indicate an initial launch into a 51-52 degree inclined orbit for NROL-69, followed by a burn into an approximately 64.4 degree inclined orbit. 

Initially I interpreted the trajectory as featuring a 'dogleg' manoeuver into 64.4 degree inclination just after launch. I later revised that, following reports from observers in Poland that they saw the Falcon 9 during its first pass over Europe, 25 minutes after launch, in a trajectory more consistent with still being in a 51-52 degree inclination orbit. In addition, reports came from western Australia about a possible remnant exhaust cloud that might have been seen there about an hour after launch. 

I therefore revised my interpretation of the launch sequence. My revised interpretation features an initial insertion into a 51-52 degree coasting orbit, followed by an insertion burn into 64 degrees inclination near the ascending node, about an hour after launch, over the Indian Ocean near western Australia. Following that, and following orbit insertion of the payload, the deorbit burn for the Falcon 9 upper stage happened over the northern Atlantic just after completion of the first revolution, and next the fuel venting seen from Europe around 20 UTC (21 CET), some two hours after the launch, during the first part of the second revolution. Deorbit of the Falcon 9 was around 20:40 UTC, 1.5 revolutions after the launch, over the Indian Ocean southeast of Madagascar (see map in top of this post).

Below are the Navigational Warnings for the launch. The hazard areas from these warninsg are plotted in red in the map in top of this post.

191844Z MAR 25
NAVAREA IV 332/25(11,26).
WESTERN NORTH ATLANTIC.
FLORIDA.
1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING
   241742Z TO 241824Z MAR, ALTERNATE
   251728Z TO 251810Z, 261714Z TO 261756Z,
   271700Z TO 271742Z, 281646Z TO 281728Z,
   291632Z TO 291714Z AND 301618Z TO 301700Z MAR
   IN AREAS BOUND BY:
   A. 28-38.31N 080-37.17W, 28-51.00N 080-14.00W,
      28-44.00N 080-03.00W, 28-30.00N 080-18.00W,
      28-27.40N 080-31.49W.
   B. 30-14.00N 078-53.00W, 31-58.00N 077-03.00W,
      32-18.00N 076-17.00W, 32-02.00N 075-57.00W,
      31-15.00N 076-21.00W, 29-55.00N 078-35.00W.
2. CANCEL THIS MSG 301800Z MAR 25.

190258Z MAR 25
HYDROPAC 711/25(61).
INDIAN OCEAN.
DNC 02, DNC 03.
1. HAZARDOUS OPERATIONS, SPACE DEBRIS
   1849Z TO 2058Z DAILY 24 THRU 30 MAR
   IN AREA BOUND BY
   23-06.00S 060-45.00E, 24-22.00S 058-21.00E,
   54-18.00S 084-05.00E, 53-02.00S 087-47.00E.
2. CANCEL THIS MSG 302158Z MAR 25.//

As 64.4 degrees is the typical inclination for a NOSS (Naval Ocean Surveillance System) duo of SIGINT satellites, and given the location and timing of the deorbit area for the upper stage, my initial suspicion was that this could be a new NOSS launch into a 900 x 1300 km 64.4 degree inclined orbit. I was wrong in this however.

Two days after the launch, in the evening of March 26, a number of European observers (Tomi Simola in Finland, Eelke Visser and me in the Netherlands, and David Brearley in the UK) managed to find the payload on-orbit, close to my search orbit. Only one object could be detected, indicating that it is not a NOSS but something else. Below is a stack of several video frames showing the object (video itself is at the end of this post):

click to enlarge

The payload, now named USA 498, was detected in a 64.1 degree inclined, ~700 x 1500 km orbit (but this is based on a very short arc so the exact orbital altitude is still up for revision). We have not seen something in this kind of orbit earlier, apart from NOSS satellites (the closest in orbital similarity otherwise is USA 327 (2022-040A), in a 1076 x 1135 km 63.4 degree inclined orbit).

The plot below shows its orbit and orbital position for the time of my March 26 observation: 

Click image to enlarge

Below is some of my video footage from March 26, showing the payload as an object of about magnitude +5 to +6 (the instrument was a WATEC 902H2 Supreme with 1.2/50 mm lens):

 

Preliminary orbit (McCants):

USA 498 (NROL-69)
1 63350U 25060A   25085.82507109 0.00000000  00000-0  00000-0 0    05
2 63350  64.0600 349.1636 0555412  27.6298 328.1938 13.37020084    05