[UPDATED] Identifying a reentry over the Canary Islands on 16 October as the reentry of the Chinese satellite Xinjishu Yanzheng 7 (XJY-7)

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In the early local morning of 16 October 2025 around 1:56 UTC, a spectacular phenomena appeared in the sky over Tenerife in the Canary Islands. A bright, slow, fragmenting fireball moved from south to north over the sky. Sonic booms were heard and registered by several seismic stations on Tenerife. The event clearly was a reentry of artificial space debris. For footage, see here and here. The all-sky image on the left above is from the Izana Atmospheric Research Center on Tenerife (the plotted sky map on the right is by me, for comparison, see discussion below).

I was alerted to the event by my Spanish colleague Josep Trigo (ICE-CSIC/IEEC) in the morning of October 16, who asked if I could identify which object was reentering here. A check on the CSpOC portal Space-Track did not yield a TIP that would match - as it turns out, the object in question never received a TIP, which is odd as it was heavy and large, as we will see.

So in order to identify it, I had to do some additional research. I selected all orbits from the orbital catalogue with perigee below 200 km. Next, I used SatEvo software to see which of these orbits would have a predicted reentry on October 15-16. From the handfull of candidates left, I next checked which of them would be over the Canary Islands near the time of the event (1:56 - 1:57 UTC on 16 October 2025). One object stood out - and it was one for which no TIP had been issued: the Chinese satellite Xinjishu Yanzheng 7 (XJY-7, 2020-102C), launched in 2020.

All sky imagery showing the reentry trail in the sky against a starry background had meanwhile been published on Twitter by the Izana Atmospheric Research Center on Tenerife. The general location of the trail amidst the stars in the sky and the direction of movement matched those expected for XJY-7 well. It was clear we had found our culprit.

Not much is known about XJY-7. Jonathan McDowell lists bus dimensions of about 3 x 5 x 9 meter and a dry mass near 3000 kg for this object in his catalogue. ESA's DISCOS lists similar dimensions but a mass of 5000 kg (perhaps a wet mass).

The last available orbit for XJY-7 was for epoch 25288.77158679, or 15 October 18:31 UTC, some 7h 25m before the event. To investigate further, I used the reentry model that my colleague Dominic Dirkx and I made some time ago (see earlier posts) in the Open Source Delft University of Technology Astrodynamics Toolkit (Tudat) to see whether I, with trial-and-error, could get a reentry model for XJY-7 to end over the Canary Islands. As it turns out, I could, for a mass of 2717 kg (close to 3 tons) and a drag area of 37.44 m² (the maximum drag surface listed by DISCOS), using past and current space weather.

The map below shows the resulting reentry groundtrack and times for this model integration. Note that the model does not take fragmentation and mass loss into account, so it has limitations and is an approximation only. I had the model terminate at 20 km altitude.

The figure below the map, compares the sky trajectory resulting from this model for the location of the Izana Atmospheric Research Center, to that registered by the all sky camera at Izana. They match well.

Click map to enlarge

 

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It is curious that no TIP was issued for this reentry by CSpOC. This was a large heavy object: 3 x 5 x 9 meter and 3 tons in mass. CSpOC apparently overlooked this reentry - a few hours post reentry, they however did add an administrative "decay message" for October 16 to the catalogue for this object, but without any further details. 

We recently have seen a complete lack of TIP's being issued for any object, for over a month. Only recently, CSpOC resumed issuing TIP's. CSpOC is currently clearly having some issues with their system. Luckily, we were nevertheless able to identify the object responsible for this spectacular reentry, by some diligent analysis.

 

UPDATE 17 Oct 2025  22:00 UTC:

Click map to enlarge (map updated to correct typo)

I played a little bit more with the reentry model, tinkering the area to mass ratio to get an even better fit to the sky trajectory as seen from the Izana camera station. Here is an updated plot of the modelled sky trajectory (numbers next to trajectory are atmospheric altitudes in km according to the simulation):

A mass of 2715.5 kg creates a very good fit, except for the end of the trail. That is no surprise: the reentry model is a simple model without mass loss and fragmentation, while in reality there is massive mass loss and fragmentation (meaning: changing area to mass ratio's for various fragments). When solid parts survive, heavy relative to their size, these have a lower area to mass ratio meaning they lose altitude less quickly.

Here is the improved model trajectory overlayed on the Izana camera image:

Click image to enlarge

(I thank Josep Trigo (ICE-CSIC/IEEC) and the Spanish SPMN for data and discussions)

[UPDATED] A post-analysis of the N-Korean launch window, and N-Korean Spooks on my weblog?

On December 12, North Korea surprised the Western world by successfully bringing its first independently confirmed satellite into orbit: Kwangmyongsong 3-2, a reportedly 100 kg cubesat. For images of the satellite and an analysis of its likely components, see here. The satellite was launched with an UNHA 3 rocket from Sohae Launch Centre in Cholsan.

The successful launch came as a surprise for two reasons. First, all previous North Korean satellite launch attempts abysmally failed (even if N-Korea claimed they were a success).

Second, North Korea had indicated days before the launch that the launch was to be postponed to late December, for technical reasons. This appears to have been a deliberate disinformation ploy by N-Korea. According to South Korean press sources, it appears they also tried to play a ruse on the Americans, by pretending to dismantle the rocket when US imaging satellites were overhead, and continuing launch preparations when they were not.




Analysing the time of launch and US satellite coverage of the launch site

Well then: did the North Koreans indeed try to evade US (and Japanese) satellite surveillance?

First, they would not have been able to evade detection of the launch itself by US infra-red early warning satellites such as the DSP satellites and SBIRS in geostationary and HEO orbit. Coverage by these satellites is continuous.

But that was probably not N-Korea's goal anyway. Their goal reportedly was to try to convince analysts of imagery from US imaging satellites (optical and radar) that the rocket was not yet complete at the launch site, and not yet ready to launch for a while. The aim was apparently to throw off US predictions about the "when" of the launch until the very moment of launch itself.

Their concern hence was with US and Japanese optical and radar imaging satellites such as the KH-12 Keyholes, Lacrosses, FIA and IGS. These imaging satellites move in LEO, and coverage is not continuous- not yet at least.

Indeed, the timing of the North Korean launch (00:49 UTC on December 12) is interesting. It coincides with the end of a one hour long interval with no coverage of the launch site by US or Japanese Low Earth Orbit imaging satellites.

By contrast, in the hours prior to and after this one-hour gap in coverage, such periods of non-coverage were much shorter (typically 10-15 minutes at best), as can be seen in the coverage analysis images below and the movie near the top of this post (movie, images and analysis made using JSatTrak).

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As can be seen from the coverage analysis, this hour long interval between 23:45-00:45 UT really stands out compared to the hours before and after. The N-Koreans launched right at the end of this interval at 00:49 UT, just when the launch site was coming into reach of the FIA Radar 2.

I feel the launch right at the end of this interval is no coincidence: they picked a moment where prior to launch they would have a substantial gap in US satellite surveillance available to complete their launch preparations. The one-hour long interval seems to have provided the North Koreans enough time to remount whatever they dismounted or camouflaged as a ruse, and launch.

(some remarks on the analysis and movie above: for a few of the satellites shown, positions are not 100% certain. For example, the Keyhole USA 186 hasn't been observed for a while because of the midwinter blackout. Satellites included in the analysis are the Japanese IGS, the US Keyholes, Lacrosses and FIA [edit: plus SPOT, Worldview and Quickbird commercial imaging satellites]).

Update 17/12 12:45 UT: 
I initially forgot to include the GeoEye Worldview and Quickbird commercial imaging satellites in the analysis. These commercial sats are frequently hired by the US government for selected imaging and used by independent analysts as well.

I have now added these satellites to the analysis, and the one-hour gap coverage between 11 Dec 23:45 and 12 Dec 00:45 UT keeps standing:

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Update 17/12 16:00 UT:
Also added the French SPOT satellites to the analysis. Again, the 1-hour coverage gap between 11 Dec 23:45 and 12 dec 00:45 UT keeps standing.

Korean Spooks on my weblog?

There is a bizarre twist to this all that involves this weblog. In the late morning of December 8th, four days before the launch, an IP solving to North Korea visited this weblog. It entered through web-searches that included the keywords 'tle', 'KH-12' and 'Lacrosse 5'. A screenshot of the web statistics is below:

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North Koreans with access to international websites are about as rare as, well, North Korean unicorns. Only a very select handful of North Koreans -mostly direct family members of Kim Jong Un- are allowed access to the internet.

Disclaimer: I was (and am) slightly suspicious. IP's can be spoofed, and two things caught my eye. One is the OS listed, Windows Xp. N-Korea is supposed to have its own OS, 'Red Star'. But then, maybe they only use this for their own, completely internal version of the internet. Or maybe western webstatistics providers cannot properly recognize it and list it as Xp (plus it could be a knock-off of Xp, even).

Second initially suspicious detail: the 10:05 and 10:07 visits have the word "satelliet", not "satellite" in the search string. That raised some suspicion as "satelliet" is the Dutch word for "satellite". However: that could also be a simple typo (switching the last two characters - a very common kind of typo) instead of a Dutchman typing.

Assuming that this was a real N-Korean visit, then the visit is highly interesting with reference to the apparent ruse played on US satellite surveillance of N-Korea as analysed above.

For here we apparently have a North Korean, a country where the average Kim is not allowed access to the internet, looking for orbital information on US surveillance satellites on my weblog!

This moreover was someone with at least some knowledge of satellites - again, not your average North Korean Kim, but suggestive of someone from the NK space program or intelligence program. The specific keywords 'tle' (two-line elements, i.e. a set of satellite orbital elements) and 'Lacrosse 5' (a US radar imaging satellite) and 'KH-12' (US Keyhole-12/Advanced Crystal optical imaging satellites, i.e. the satellites USA 129, USA 161, USA 186 and USA 224) bear this out.

Yet this person wasn't perhaps entirely informed. He or she searched for orbital information on those US optical and radar imaging satellites that form the backbone of US space-based surveillance, but notably missing from the search queries is the most recent addition to the US radar surveillance constellation, the two FIA Radar satellites. Also missing are Japan's IGS satellites. But, maybe, after checking for the KH-12 and Lacrosse 5 they realized they should not be on my blog for this information - they should be at Mike's website for that.

Fireball over N-Europe on 21 September 2012, 21:45 GMT was likely NOT a reentry

UPDATE (24/9/2012): more and definite arguments that this was not a reentering satellite, can be read here in my follow-up post from Sep 24th. This includes a first rough trajectory reconstruction for this fireball.

Reports are pouring in from The Netherlands, Britain, Ireland and other N-European countries about a very bright, extremely slow fragmenting fireball appearing around 21:45 - 21:55 GMT (23:45 -23:55 CEST) on the evening of 21 September 2012.

Various video's have been posted on Youtube, notably by observers from Britain (large parts of the Netherlands were clouded out, including the all-sky stations):





Because of the unusually long duration and slow movement, some people have suggested the possibility of a satellite reentry. For various reasons, this is however very unlikely.

Multiple reports make clear the object was moving from east to west. A report of observers from Bussloo Observatory, the Netherlands, for examples states that the fireball appeared in the north, moving from Perseus  to Bootes, almost horizontally from east to west. Similar reports (e.g. here and here) come from Ireland.

Almost all non-polar satellites move prograde,  from west to east (or north-south and v.v. for a polar orbit). An east to west movement would necessitate the object to have a retrograde orbit (meaning that it moves counter to the earth's direction of rotation). Such objects are extremely rare: they literally amount to only a handful of objects (including the US FIA Radar satellites, and the Israeli Ofeq/Shavit satellites/rb). For this reason, it is extremely unlikely that this fireball was a reentering satellite.

Update 24 Sep: in the comments to this blog post, the issue was raised of the potential reentry of a classified object. However, the larger classified pieces are tracked by us amateurs. We have no likely decay candidates among the retrograde objects that we track. We can account for and hence exclude the FIA's for example (the rocket bodies of that launch were deliberately de-orbitted right after launch so are no candidates either). The Israeli Ofeq/Shavit are no candidates as their orbital inclinations never take them over the Netherlands and the British Isles. And there are simply no other suitable retrograde objects -- end of update.

There are moreover no unclassified reentry candidates for this date listed by USSTRATCOM on their space-track portal. Given the brightness of the fireball, this should have been a seizable chunk of space debris, that really would have been tracked (and predicted). Again, this makes it very unlikely that this fireball was a satellite reentry.

While the duration of the fireball is unusual, it is not unprecedented. In many ways, the descriptions and video are reminiscent of the Peekskill fireball that dropped meteorites near Peekskill in 1992:

(below: two video's of Peekskill fireball, 1992)

It is therefore my opinion that the 21 September fireball was most likely of meteoric origin: a chunk of asteroid. Alas, any surviving remains appear to have splashed down in sea (update: or possibly Scotland - N. Ireland).

The duration of the event, though not unprecedented, is certainly unusual and for this reason, I am saying "most likely not" rather than "certainly not".

UPDATE (12:45 GMT, 22 Sep):  another bright fireball was widely seen from the US and Canada that same night near 20:30 GMT. There was at least one hour inbetween the two events, so they do not appear to be related (i.e. they do not concern the same fireball).

UPDATE 2 (13:30 GMT, 22 Sep): Suggestions that the fireball might be related to Chinese CZ-4 space debris, catalogue #26213, are plainly incorrect. That object (and any fragments of it) are in a 98 degree polar orbit. This is completely incompatible with the reported movement of the fireball. As seen from Bussloo in the Netherlands and Dublin in Ireland, the fireball moved perpendicular, not parallel, to the orbital plane of this Chinese space debris (and that of any related fragments).

 IMPORTANT UPDATE 3 (24/9/2012): more and definite arguments that this was not a reentering satellite, can be read here.

Feb 15 Texas-Nebraska daylight fireball was NOT satellite debris

Sightings of a bright daylight fireball seen from Texas to Nebraska on February 15th, have been widely reported in the press.

Contrary to what the FAA appears to be stating, this was definitely NOT debris from the collision between the Iridium 33 and Kosmos 2251 satellites on February 10th.

Video footage of the fireball (see below) shows that it moved clearly too fast for that, and was of too short duration, to be decaying satellite debris. In stead it is in line with a meteoritic fireball (asteroidal debris).

There is a clear difference in speed between the two categories: asteroidal/cometary debris moves at at least 11 km/s (and usually much faster) and typically lasts only a few seconds (as this fireball did). Satellite debris decaying moves at 7.5 to 8 km/s, so clearly slower, and typically has a much longer duration (due to the slower speed, but also because it enters at shallow angles). The video footage is incompatible with the appearance of decaying satellite debris. It is completely compatible with a meteoric fireball (asteroidal debris).