Possible Space Debris impact in Kenia: a piece of the Ariane SYLDA 2008-034C? [updated]

the metal ring found near Mukuku in Kenia. Image: Kenia Space Agency

the metal ring found near Mukuku in Kenia. Image: Kenia Space Agency

the metal ring found near Mukuku in Kenia. Image: Kenia Space Agency

 

On 30 December 2024, reportedly near 12:00 UTC, an odd object is believed to have fallen from the sky near the village of Mukuku in Kenia (approximately 1.58 S, 37.61 E, some 100 km from the Kenian capital Nairobi). It is metal ring of about 2.5 meter in size and reportedly 500 kg mass, although that mass could be an estimate only.

The Kenya Space Agency is investigating, believing it to be Space Debris. Apart from the metal ring in the pictures, other fragments looking consistent with space debris, for example what looks like carbon wrap and isolation foil, were found several kilometers away from it (see video below):

 

It is still not entirely clear if the object is space debris (although it looks likely), and if so, which object from what launch. There are two reentry candidates for this date, only one of which looks viable as a candidate (see also Jonathan McDowell's summary here).

That viable candidate is object 33155 (2008-034C), an Ariane SYLDA adapter from flight V184, the launch of ProtoStar 1 and BADR 6 to geosynchonous orbit on 7 July 2008. This SYLDA adapter was left in a 1.6 degree inclined GTO following the launch and had its reentry on or near December 30. 

As I will investigate below, using a reentry simulation, both the location where the ring was found and the reported fall time are realistic for it to be this object.

CSpOC, the US military tracking network, last recorded 2008-034C in a 1923 x 146 km orbit on December 23, i.e. a week before the Kenia impact. As this is a very low inclination orbit (1.56 degrees), it belongs to a class of objects that is ill-tracked due to a lack of tracking stations close to the equator. This explains the 1-week gap between the last available orbit and the reentry.

As a note: what is a SYLDA? A SYLDA ("SYstème de Lancement Double Ariane") is a kind of hollow shell put over the first payload, in order that a second payload can be mounted above it.The conical upper part of the SYLDA has a smallest diameter near 2.6 meter, i.e. similar to the size of the ring found in Kenia, which then could be an upper Payload Adapter Fitting (PAF).

A SYLDA (black) as part of a stage, satellite and fairing stack (image: ESA)

An Ariane SYLDA (image: ESA)

CSpOC issued a reentry TIP for this SYLDA for 30 December 2024, 21:38 UTC +- 59 minutes. That is the date of the Kenia event, but not the correct time, as the Kenia event reportedly happened near 12:00 UTC, nine hours earlier. However, the quoted uncertainty of 59 minutes from this TIP is not realistic, if based on the last available orbit (a week old at the time!). A more realistic uncertainty estimate would be +- 1.5 days. 

Ignoring the CSpOC TIP time, I did an independent impact prediction, using the development version of the open source TU Delft Astrodynamics Toolbox (TUDAT).

I used the last available orbit (epoch 24358.42010446) and the nrlmsise00 model atmosphere to run a reentry prediction, using a trial-and-error approach to see whether I could tinker with the drag area such that it would reenter near 1.58 S, 37.61 E near 12:00 UTC on December 30. 

From @DutchSpace on twitter, who is very knowledgeable on Ariane hardware, I got a mass of 505 kg for the SYLDA in question. The dimensions for the SYLDA on flight V184 should have been about 4.5 x 6.4 meter (there are different versions of SYLDA with different mass and sizes).

After some trial-and-error, I can make the object reenter at 1.57 S, 37.61 E  on 30 December 2024 at 11:49 UTC, close to the reported location and time, if I use an average drag area of ~18.24 m². That is a value which is about 63% of the maximum drag area of this SYLDA (roughly 28.8 m²). This is a reasonable value: during earlier reentry analysis for elongated objects like rocket stages (or in this case, a hollow elongated adapter), I found that a drag area of about 60% - 62% of the maximum area is usually a good approximation to account for the variability in drag due to tumbling .

Below is what the approach trajectory from this simulation would be:

click map to enlarge

While my TUDAT simulation does not prove that the object is debris from 2008-034C (SYLDA), it does show that it is feasible for the reported time and location.

How about that 'other' candidate? That was an Atlas Centaur booster, 2004-034B, for which CSpOC gives a TIP of 30 December 2024 21:30 +- 1 m UTC. However, the orbital plane of this candidate did not pass over Kenia at the reported time (12:00 UTC), and moreover, this object was still detected on-orbit several hours after the reported time of the Kenia event (see also Jonathan McDowell's analysis here): the last reported orbit is for epoch 30 December 2024 15:50 UTC (but it is always possible that a part came off earlier). For these reasons, it is not that likely that the Kenia event was due to a part of this object.

@DutchSpace on twitter, who as mentioned is very knowledgeable on Ariane hardware, so far has trouble positively identifying the ring as a SYLDA part (and that worries me). If the reported mass of 500 kg is correct, that is too heavy for it to be part of this SYLDA too. I have some suspicion however that the reported mass is an overestimate.

For now the verdict is: possibly the reentry of parts of the Ariane SYLDA 2008-034C, but not proven beyond doubt yet.

Here is the final output [revised after running both a TUDAT and TUDAT script update] of my TUDAT reentry model (I had it stop at 50 km altitude, as at that altitude the object should have completely fragmented and decelerated, with fragments falling down basically vertically):

mass: 505 kg
drag area: 18.236375 m^2
altitude limit: 50000.0 meter

propagation start: 2024-12-23 10:04:57.030000 UTC
propagation end:   2024-12-30 11:49:25.029545 UTC
final altitude:    49.879

reentry after 7.072 days

REENTRY AT:
2024-12-30 11:49:25.029545 UTC
lat: -1.57
lon: 37.61

Values in the last three lines are nominal only, the error margins over a 7-day integration period are large. Also ignore the superfluous digits. As a reminder: I tinkered with the drag area untill I got a value that made it reenter as close to 1.58 S, 37.61 E and 12:00 UTC as possible, and the above output gives the relevent drag area and the resulting modelled reentry time and location.

The TUDAT script used can be downloaded here (note: you have to use this script with the 'development version' of TUDAT, as the current non-development release of TUDAT has a bug where the epoch of a TLE is incorrectly read). The development version of TUDAT and installation instructions can be found here.

UPDATE 9 Jan 2025:

In a statement to Gaël Lombart of Le Parisien, Arianespace engineers have cast doubt on the identification of the crashed object as a SYLDA part, indicating that the size of the ring does not fit and stating that "this part does not belong to an element of a European launcher operated by Arianespace". So the mystery remains as to what this object's origin is.

Objects from the Ariane VA240 launch (Galileo 19, 20, 21, 22) observed from the Netherlands [UPDATED]

image 18:53 ~ 18:56 UT. Photograph (c) Klaas Jobse, Astronomy Project Oostkapelle
click to enlarge

On 12 December 2017 at 18:36:07 UT, an  Arianespace Ariane 5 ES rocket launched four Galileo navigation satellites into space from Kourou, French Guyana, for the European Space Agency (ESA).

Twenty minutes later, amateur astronomer Klaas Jobse (Astronomy Project Oostkapelle) in the village of Oostkapelle on the coast of the Netherlands imaged a phenomena in the sky (photograph above and photographs below). The imagery appears to show the tumbling Ariane EPC (Cryogenic Main Stage) and what appears to be a fuel dump cloud, about 10 minutes after separation of the EPC from the upper stage.

In one of the all sky images, a second trail is visible too (see detail image of all sky image below): this might be the EPS Upper Stage with the satellites, around the moment it shuts down and starts its coasting phase.

All Sky image. (c) Klaas Jobse, Astronomy Project Oostkapelle
click to enlarge

detail of the previous image.
(c) Klaas Jobse, Astronomy Project Oostkapelle
click to enlarge

All Sky image. (c) Klaas Jobse, Astronomy Project Oostkapelle
click to enlarge

detail of the previous image.
(c) Klaas Jobse, Astronomy Project Oostkapelle
click to enlargee

The flashing behaviour of the main trail (the suspected spent Cryogenic Main Stage) is probably due to tumbling after separation from the upper stage. On the first image (the one at the top of this post), which is a 30 seconds exposure, it is flashing 9 times, or about once every 3.3 seconds.

The images were captured by the automated routine meteor fireball patrol camera's of Astronomy Project Oostkapelle, which make continuous photographs of the night sky every clear night.

This is the approximate trajectory of the launch which I reconstructed from the Area Broadcast Warnings and information in the Arianespace presskit. It is approximate only:

click map to enlarge

Update 1, 13 Dec 2017, 23:00 UT:

The map above was based on ascend to the parking orbit of the Upper stage. Below is a 178 x 3440 km, 54.95 degree inclined reconstructed orbit for the EPC Cryogenic Main Stage, fitted to match measurements on the first image (the image in top of this post). Orbital position shown is for 18:56 UT:

click map to enlarge

 The rocket stage probably de-orbitted near the end of the first revolution, at about 20:40 UT.


 Update 2, 14 Dec 2017, 22:45 UT:

An engineer supporting the launch (@Dutchspace on Twitter) provided the info that the EPC Cryogenic Main Stage should have been in a 42 x 3340 km, 55.35 degree inclined orbit after separation and depressurization, with de-orbit at longitude 90.28 W. The elset and map below suit those constraints, and fit the observations from Oostkapelle closely:

click map to enlarge

Ariane EPC r/b                                           42 x 3340 km
1 70004U 17999C   17346.77516204 0.00000000  00000-0  00000+0 0    07
2 70004  55.3500 305.8931 2043588 353.6368 349.8559 11.97683367    04

rms 0.06


Update 3, 16 Dec 2017, 11:00 UT:

The phenomena was also imaged from Germany (see this article in Der Spiegel, which quotes me) and from Belgium.


(I thank Klaas Jobse for permission to publish his photographs. Photographs (c) Klaas Jobse, Astronomy Project Oostkapelle)

Images and video of ESA's Space Cargo Ship ATV-4 'Albert Einstein' over Leiden

(click image to enlarge)

ATV-4 passing over the historic observatory of Leiden, 1:21 UT

stack of 8 images

ESA successfully launched its 4th cargoship ATV-4 Albert Einstein from Kourou last night at 21:52 UT, loaded with cargo destined for the International Space Station ISS.

Following the launch it made two visible passes over Leiden, the first of these two hours after launch at 23:47 UT (1:47 am local time) and a second in morning twilight at 1:20 UT (3:20 am local time). The sky was clear and I could observe both passes well.

I used both my Canon EOS 60D photocamera and my WATEC video camera to image the passes. Above is a photograph shot during the second pass (1:21 UT), showing the ATV descending over the old historic Observatory of Leiden. The image is a stack of 8 images of 5 second exposure each, taken in rapid succession. The lens used was an EF 2.8/24mm.

Below is a video shot during the first pass at 23:47 UT. The ATV, faint at first but then quickly becoming quite bright, can be seen ascending just right of the house in the opening shots:



Note how from 50 seconds in the video onwards, TWO objects are visible: a fainter object (about magnitude +4) is leading the ATV by a few seconds. This is the Ariane upper stage. It is also visible on the photograph below, taken with an EF 2.0/35mm lens:

click image to enlarge

ATV-4 was very bright on both passes and easily seen by the naked eye: magnitude +1 on the first pass and +0.5 on the second. It moved quite fast, being in a low orbit at an altitude of about 280 km.

In fact, ATV-4 made a third pass this nigh only 20 minutes after launch, near 22:12 UT (00:12 local time). As it was not entirely clear whether the ATV would be in earth shadow or illuminated  during this pass (this early in the launch it is at still very low altitude, below 150 km) I did watch, but as expected it was in earth shadow and not visible.

Below are two more pictures from the 23:47 pass. One shows the ATV ascending in the west, close to the Coma berenices cluster. The second one shows it descending in the east, and shows two other (unrelated) objects: and old Russian Soyuz r/b, and the US military satellite NOSS 2-3 E.

click images to enlarge

Space debris lands in Brazil village

Through Carlos Bella on the satobs mailing list, news broke today that an object which almost certainly is space-debris crashed in the Brazilian village of Anapurus on February 22, 2012, near 6 am local time (9 UTC). It landed about 6 yards from a house and damaged trees upon impact.

Photo's of the object can be see here.They show a spherical object that strongly resembles a spherical rocket fuel cell (tank) or a Helium pressurization tank. These are the most resistent objects among space debris and often involved in reported cases of space-debris reaching earth surface.

Ted Molczan quickly noted that date, time and location correspond well to the re-entry of 1997-016C, an Ariane 44L rocket stage from the launch of two geostationary satellites, Thaicom 3 and Bsat-1A, on 17 April 1997.

The Ariane 44L r/b in question re-entered at 9:09 UTC +/- 1 min on 22 February 2012, near 4 S, 312 E. This corresponds well with the time and location of the Anapurus event (3.7 S, 317 E). Anapurus is located right on the re-entry track and was passed within a minute of the estimated re-entry time (movement of the r/b was from West to East, i.e. to the right in the map):

click map to enlarge