THE SECRET SPIES IN THE SKY - Imagery, Data Analysis, and Discussions relating to Military Space
SatTrackCam Leiden (Cospar 4353) is a satellite tracking station located at Leiden, the Netherlands. The tracking focus is on classified objects - i.e. "spy satellites". With a camera, accurate positional measurements on satellites of interest are obtained in order to determine their orbits. Orbital behaviour is analysed.
This blog analyses Missile tests too.
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 Russianspace 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.
ionospheric glow caused by Starfish Prime, a 1962 nuclear detonation in Space (image: Wikimedia)
It sounds a bit like the fictituous Goldeneye satellite from the 1995 Bond movie of that same name: a secret Russian weapon in space waiting to unleash doom.
The past few days the media have been abuzz about a purported Russian Space Weapon, either nuclear or not, either deployed or not.
The initial source was US Congressman Michael R. Turner, chairman of the House Intelligence Committee, who in an unprecedented public letter to House members said he had concerns about a "serious national security threath", urging President Biden to declassify the information. Subsequently, various US news sources quoted various of the proverbial "anonymous sources", with often conflicting information about the nature of the threath, but all indicating some kind of Russianspace weapon.
What kind of weapon exactly, is unclear, although it seems to be an Anti-Satellite weapon of some sorts (see below). What caught the attention is that the 'anonymous sources' seemed to indicate something nuclear: either a nuclear weapon in space, or a nuclear poweredsatellite. Whether this is correct or not or just paranoia, is unclear at the moment.
A spokesman of the US White House National Security Council, ret. Admiral John Kirby, in reply briefed the press but with little pertinent extra information, apart from stating that he could confirm that "itis related to an anti-satellite capability that Russia is developing":
He also made it clear that it is "not an active capability that has been deployed". In other words, there is currently not a weapon already lurking in space. And, he did clarify that it does not concern something targetting objects on the Earth surface.
It should also be noted that Kirby did not unambiguously mention (see below for what I exactly mean with that) that the 'capability' in question is nuclear, so this remains an unverifiable rumour from anonymous sources that might or might not be wrong.
However, at 26:45 into the press conference, he does confirm that this Russian capacity is 'space-based': i.e. not a kinetic interceptor fired from earth, but a weapon to be deployed on-orbit; and he states, interestingly enough, that it "would be a violation of the Outer Space Treaty".
The latter is an interesting phrasing and could perhaps be taken to indicate something nuclearafter all (but: see what is following), as the 1967 OST, to which Russia is a signatory State, in article IV of the Treaty prohibits the deployment of Weapons of Mass Destruction (and very specifically nuclear weapons) in space.
On the other hand, the remark of "violating the OST" might simply refer to Article VII, that holds parties to the OST responsible for any damage they inflict in space on satellites from other Nations; or Article IX that says that signatory States should avoid "harmfull contamination" of Space (such as the creation of harmfull space debris from an ASAT test).
So it all remains ambiguous here and the 'capability' in question might not have any nuclear aspects (e.g. being nuclear-powered, which is not a violation of the OST, or a nuclear weapon, which is) at all, depending on how you interpret the wording of Kirby's statements. There is a lot of interpretational wiggle room here.
That Russia is pursuing anti-satellite (ASAT) capabilities is nothing new. In November 2021, they conducted a much-criticized kinetic ASAT test targeting and destroying their Kosmos 1408 satellite (see my earlier posts here and more elaborate here) that created orbital debris in Low Earth Orbit and made astronauts and kosmonauts onboard the ISS briefly take shelter in their Soyuz capsule.
The new element of the capability that is now the subject of all this discussion, appears to be that it is to be space-based. But even that is not really new. Over the past years, there has been much concern about Russian proximity operations in space (Russian satellites approaching other satellites, either Russian or from other countries, very closely: or ejecting sub-satellites/apparent projectiles).
In 1987, the former Soviet Union attempted to launch a prototype space-based laser weapon, Polyus/Skif (that launch failed). Maybe they are up to something like that again. And for a long time, it is said that Russia is working on a nuclear-powered electronic warfare satellite, Ekipazh.
proximity operation of the Russian LUCH/OLYMP 2 SIGINT satellite close to a commercial geostationary satellite, as seen in this image I made from Leiden on 20 Sept 2023
In general, ASAT weapons are usually not weapons that are smart to use, as they do more harm than good.
Both kinetic ASAT weapons (that destroy satellites and in that process generate a lot of potentially harmful orbital debris) and nuclear detonations in space for use as ASAT, are indisciminate weapons that do not only harm your target, but potentially also harm other satellites, including your own satellites and those of Nations not part of the conflict in question.
This is not the case for every ASAT weapon though. For example, a weapon that would attach to a target satellite and mechanically or electronically sabotage it, would be less harmfull to other satellites, although it does produce at least one piece of space debris, a dead satellite.
[clarification added 17:30 UTC on 16 Feb 2024: The paragraphs below discuss a nuclear EMP device in space. There is however another option, that of a nuclear powered but in itself not nuclear ASAT weapon, where a nuclear reactor provides the power source for another type of weapon, e.g. a very powerful laser(see the mention of Polyus above) or radio jammer (see the mention of Ekipazh above). This was one of the SDI concepts back in the 1980'ies. Nuclear powered satellites in itself are not new: both the Soviet Union and the USA have used them in the past, for example the Soviet RORSAT's that used nuclear power to power a powerful radar. Nuclear powered satellites do not violate the OST.]
As the nuclear spectre was raised by the 'anonymous sources'
(which could have political agendas to do so), let's discuss this for a
moment. Before the OST came into effect, Nuclear weapons tests have actually been conducted in space. And the results were very concerning.
The most well known of these is the US Starfish Prime test of 1962, part of Operation Fishbowl, where a 1.4 megaton nuclear bomb launched by a Thor rocket was detonated in Space at 400 km altitude. But there were also three smaller, earlier, low yield US tests in 1958 as part of Operation Argus.
Starfish Prime surpassed all expectations, leading to a halt in this kind of testing. Detonated at 400 km altitude over Johnston atoll, the Electro-Magnetic Pulse (EMP) created by the nuclear detonation actually inflicted damage at ground level on Hawaii, 1450 km away, where it knocked out some streetlights and parts of the telephony network.
(Note that in our modern world, where lots of electronics work based on microprocessors which are very vulnerable to EMP, we are much more vulnerable to such effects than the world was in 1962).
1962 Starfish Prime detonation flash as seen from Honolulu (image; Wikimedia)
ionospheric glow caused by charged particles from the 1962 Starfish Prime detonation (image: Wikimedia)
In addition, charged particles generated by the detonation and carried along the Earth's magnetic field damaged several satellites.
Of the 25 satellites in earth orbit on that date (this was the early space age), nine were damaged and eventually failed early as a result of this test. It concerned seven US satellites, one UK satellite, and one Russian satellite.
The damage is done by beta particles and electrons generated by the detonation, which spread through the earths magnetic field and ionosphere (which includes a considerable part of Low Earth Orbit), and damage electronic components in satellites. Some of these particles can linger on in the ionosphere for quite a long time (months).
In addition, the charged particles released into the ionosphere by the test generated Aurora-like effects on low latitudes, generating conditions that speed up the orbital decay of satellites.
In other words: using a nuclear bomb as an ASAT weapon in space, is not a very sensible approach. I would be surprised if Russia would use such a weapon, as its side-effects potentially could criple its own space assets too.
[note added 18 Feb 2024:] And it might actually do less harm to western military satellites (the ones Russia would want to target) than to civilian satellites, as several critical military space platforms have actually been hardened against EMP.
update 18 Feb 2024: CNN has published a story that is getting some traction, where it appears to be claimed that the 'weapon' in question is in fact an EMP device.
But it is again based on anonymous sources: and anonymous sources so far have been contradictory in this, and there could be political agendas behind such 'anonymous' statements. Only a few years ago, a group of hawks in US politics were trying to push the alarmistic story that North Korea was developing (and even would already have tested, a claim which is certainly bogus) space-based EMP weapons (a dark interpretation of North Korea's KMS satellites). Their agenda was that they were advocating for a preemptive strike on North Korea.
(note: added a few sentences on the 1980'ies Soviet space-based
laser weapon Polyus/Skif and the Ekipazh concept a few hours after the
initial version of this post appeared).
In my previous post I discussed the November 15 Anti-Satellite (ASAT) test on the defunct Kosmos 1408 satellite by Russia. On December 1, CSpOC released the first sets of orbital elements
for debris fragments created by the test. As of yesterday 2 December,
when I made the preliminary analysis presented below, orbits for 207
fragments were published (many more will probably be added in the coming
days and weeks).
They allowed to construct the Gabbard-diagram below, which for
each debris fragment plots the apogee altitude (blue) and the perigee
altitude (red) against orbital period. They also allowed a preliminary analysis on the delta V's (ejection velocities) imparted on the debris fragments by the intercept.
click diagram to enlarge
Let's first discuss the Gabbard diagram. Gabbard diagrams show you at a glance what the altitude distribution of the created debris fragments is. As can be seen, most of the debris has a perigee (lowest point in the elliptical orbit) near the original orbital altitude of the Kosmos 1408 satellite (490 x 465 km: the intercept happened at an altitude of ~480 km): but a part of the generated debris evidently has been expelled into orbits with perigees (well) below that altitude too. The apogee altitudes (highest point in the elliptical orbit) are mostly scattered to (much) higher altitudes. In all, debris moves in orbits that can bring some debris as low as 185 km and as high as 1290 km. As can be seen, the debris stream extends downwards into the orbital altitudes of the ISS and the Chinese Space Station. About 35% (one third) of the currently catalogued debris has a perigee altitude at or below the orbit of the ISS: about 18% at or below the orbit of the Chinese Space Station. Upwards, the distribution extends well into the altitudes were many satellites in the lower part of Low Earth Orbit are operating, with the bulk of the debris reaching apogee altitudes of 500 to 700 km.
The plots below show the altitude distributions for apogee and perigee of fragments as a bar diagram:
Distribution of perigee altitudes. Click diagram to enlarge
Distribution of apogee altitudes. Click diagram to enlarge
From the change in apogee and perigee altitudes and change in orbital inclination of the debris fragments in comparison to the original orbit of Kosmos 1408, we can calculate the ejection velocities (delta V) involved. It is interesting to do this and compare it to similar data from two other ASAT tests: the Indian ASAT test of 27 March 2019 and the destruction by an SM-3 missile of the malfunctioned US spy satellite USA 193 on 20 February 2008.
In the plot below, I have plotted the density of debris against ejection velocity (in meter/second) for the Nov 15 Russian ASAT test as a bar diagram (with bins of 5 m/s: the blue line is the kernel density):
click diagram to enlarge
In the diagram below, where I have removed the bars and only plotted the kernel density curves, a comparison is made between ejection velocities from the Russian ASAT test and the Indian and US ASAT tests of 2019 and 2008:
click diagram to enlarge
The two diagrams below do the same, in combined bar-graph form, for both the earlier ASAT tests. The first diagram compares the delta V distribution from the Russian ASAT test (blue) to that of the 2008 USA 193 destruction (red); the second diagram does the same but compared to the 2019 Indian ASAT test:
delta V of Russian ASAT fragments vs USA 193. Click diagram to enlarge
delta V of Russian ASAT fragments vs Indian ASAT. Click diagram to enlarge
The diagrams clearly show two things: the distribution of ejection velocities from the Russian ASAT test peaks at lower delta V's than that of the debris from the USA and Indian ASAT tests. In addition, the distribution is more restricted, lacking the tail of higher ejection velocities above 200 meter/s present in the distribution from the other two ASAT tests (we should note here however that this is all still based on early data, and addition of new data over the coming weeks might alter this picture somewhat).
This tallies with what we know about the Russian ASAT test: rather than a head-on encounter with the interceptor moving opposite to the movement of the target, such as in the 2008 American and 2019 Indian ASAT tests, the Russian ASAT intercept was performed by launching the interceptor in the same direction of movement as the target (as shown by NOTAM's related to the launch of the interceptor, see map below), letting the target "rear-end" the interceptor. This results in lower kinetic energies involved, explaining the more compact fragment ejection velocity distribution emphasizing lower ejection velocities. In addition, the possible use of an explosive warhead on the interceptor rather than a kinetic kill vehicle might have some influence.
click map to enlarge
So the Russian test seems to have been designed to limit the extend of ejection velocities and from that limit the extend of the orbital altitude range of the resulting fragments. That is in itself commendable, but it doesn't make this test less reckless or irresponsible.
The Gabbard diagram near the top of this post, and the bar graphs below it, show that debris was nevertheless ejected into a wide range of orbital altitudes, from as low as 200 km to as high as 1200 km, with a peak concentration between 400 and 700 km altitude. The orbital altitude range of the debris includes the orbital altitudes of crewed space stations (ISS and the Chinese Space Station), thereby potentially endangering the crews of these Space Stations, as well as the busiest operational part of Low Earth Orbit. The diagram below gives the perigee altitude distribution of objects (including "space debris") in Low Earth Orbit, for comparison (note, as an aside, the prominent peak caused by the Starlink constellation at 550 km).
In the hours following this, news broke that Russia had conducted a 'destructive Direct Ascent ASAT missile test' that morning, and it quickly transpired that both events were related. US Space Command and later, in a press conference, the spokesman of the US State Department announced that a Russian direct ascend ASAT test had destroyed an old defunct Russian Tselina satellite, Kosmos 1408 (1982-092A) launched in 1982. The ASAT test created over 1500 trackable orbital pieces of debris and probably hundreds of thousands of smaller particles, according to US Space Command.
Some of these orbital debris pieces seem to have threathened the International Space Station within hours of the event (a situation somewhat reminiscent of the plot of the movie 'Gravity'), almost immediately showing how reckless and dangerous such a destructive test is.
A set of two Navigational Warnings (HYDROARC 314/2021 and HYDROARC 316/2021) issued a few days before the test, point to a missile launch from Plesetsk towards the pole. The two Navigational Warnings in question:
HYDROARC 314/2021 (38)
ARCTIC. LAPTEV SEA. RUSSIA. DNC 27. 1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING 150200Z TO 150500Z NOV, ALTERNATE 170200Z TO 170500Z NOV IN AREA BOUND BY 83-00N 099-00E, 83-00N 137-00E, 77-10N 137-00E, 76-00N 134-30E, 77-20N 121-40E, 77-50N 109-40E, 78-20N 106-50E, 78-40N 106-50E, 80-30N 099-00E. 2. CANCEL THIS MSG 170600Z NOV 21.
091740Z NOV 2021 NAVAREA XX 184/21 091732Z NOV 21.
HYDROARC 316/2021 (42)
BARENTS SEA. RUSSIA. DNC 22. 1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING, 0200Z TO 0500Z DAILY 15 AND 17 NOV IN AREA BOUND BY 68-33.1N 047-36.2E, 68-20.3N 048-45.3E, 67-01.4N 046-43.0E, 67-13.0N 045-51.0E. 67-53.1N 046-50.3E. 2. CANCEL THIS MSG 170600Z NOV 21.
101800Z NOV 2021 NAVAREA XX 187/21 101728Z NOV 21.
Kosmos 1408 made two passes over the relevant polar region during the
time window of the two Navigational Warnings, one near 2:52 UT and one near
4:27 UT (Nov 15), with the 2:52 UT pass particularly lining up well
with the apparent missile trajectory (making it likely that the ASAT
test was conducted around that time).
This can be seen in the map below, which shows the two areas from the Navigational Warnings, as well as Plesetsk, and the trajectory of Kosmos 1408 during the time window of the warnings (2:00-5:00 UT). The relative geometry of the apparent missile trajectory and the satellite trajectory shows that this test had the kill
vehicle approach the target from behind, rather than head-on.
[edit 16 Nov 2021 9:14 UT: as Richard Cole rightly remarked in the comments, it is unlikely that the interceptor reached the same orbital speed as the satellite, so rather than the interceptor coming 'from behind', it was probably more: launch the interceptor in the same direction of movement as the satellite, while making sure it ends up slightly in front of the target, and then let the target rear-end the interceptor]
click map to enlarge
Jonathan McDowell has shown that the time window during which the ISS astronauts were instructed to retreat to their spacecraft for safety, coincides with the International Space Station passing through the orbital plane of Kosmos 1408, so the two events seem definitely linked.
Here is the orbit of ISS (blue) compared to that of the Ikar No. 39L satellite (cover name Kosmos-1408) (magenta) and the part of the orbit where the crew have been warned of possible collisions with a debris field (red). This shows Kosmos-1408 is a plausible candidate pic.twitter.com/oGJtQxWxkV
Kosmos 1408 moved in a 82.56 degree inclined, 490 x 465 km orbit. This is somewhat (but not much) higher in orbital altitude than the 424 x 418 km orbit of the ISS, but as the destruction scattered the debris in orbital altitude, the event evidently generated debris at ISS altitudes too.
As Kosmos 1408 was in a polar orbit, the ISS passes through the orbital plane of the former satellite twice during each 1.5 hour revolution around the earth, i.e. some 31 times each day. As the orbits of debris pieces decay over time, more fragments than currently already are at that altitude will reach the ISS orbital altitude. This process will probably continue for a long time to come (months to years).
Over time, the debris will spread and the orbital planes of the debris pieces will spread: as the Kosmos 1408 orbit was polar, this means that eventually the debris layer will envelop virtually the whole globe, threathening all inclinations in Low Earth Orbit. It is clear that there is a serious increase of risk here.
In my opinion, this destructive, debris-generating Russian ASAT test therefore was extremely reckless and highly irresponsible. It endangers other satellites (e.g. Starlink satellites in their initial insertion orbit, and many cubesats, as well as several 'normal' satellites in the lower part of Low Earth Orbit. And at almost each launch, the launch vehicle will have to move through the debris layer), and it endangers the inhabitants (including Russian kosmonauts!) of the International Space Station. Following the Chinese ASAT test from 2007 (of which debris is still orbiting) and the Indian ASAT test of 2019, this new Russian test again has significantly added to space debris in Low Earth Orbit, peppering it with large numbers of debris pieces.
It once again underlines the urgent need for a treaty that prohibits these kind of utterly reckless destructive on-orbit anti-satellite tests.
Recently, a group of SSA and Space Policy professionals have started a movement to call for a test ban on ASAT activities. Perhaps, the Russian test was an opportunistic act to get in a quick live shot before the movement to end these kind of activities in space gains any real traction.
It took some two years for debris from the 2019 Indian ASAT test to clear (one tracked debris fragment from that test is currently still in orbit), and that test was perfomed at a clearly lower altitude (285 km) than the current Russian test (~480 km). The initial spread in orbital altitude and eccentricity of the debris fragment created might be somewhat different due to different intercept configurations, but we can expect debris to be around for quite a while.
[This is a developing story. as more information hopefully comes availabe in the coming days or weeks, I might update this blogpost accordingly]
Today it is one year ago that India performed an ASAT test codenamed 'Mission Shakti'. The test consisted of the on-orbit destruction of the Microsat-R satellite (2019-006A), launched specifically to function as target for this test. The intercept occurred at 285 km altitude, but created debris pieces with apogee altitudes much higher than that. I have earlier published an extensive OSINT analysis of the test in The Diplomat of 30 April 2019.
The test generated large amounts of debris. A total of 125 larger debris pieces have been tracked and catalogued by the US tracking network. Note that these only concern larger pieces: most of the generated debris probably was too small to be tracked.
Over the past year I have periodically posted an update on the status of these larger debris pieces on this blog. Whereas the Indian DRDO claimed at the time that all debris would have been gone 45 days after the test, the reality has been quite different: 45 days after the test, 29% (less than a third) of the larger debris pieces had reentered. It took 121 days for half of the pieces to reenter, and some 200 days before 75% of the tracked debris pieces had reentered.
One year after the test, some 114 of the tracked debris pieces have reentered according to CSpOC tracking data. And two more objects for which no
decay message was published by CSpOC, 2019-006AR and EA, have reentered according
to my own analysis with SatEvo, bringing the total tally of reentered larger tracked pieces to 116.
Nine, or some 7%, of the original 125 larger tracked debris pieces are still on orbit.
It concerns objects
2019-006V, AJ, AX, BD, DC, DD, DE, DM and DU (red orbits in the image below: the white orbit is that of the ISS, as a comparison). They have apogee altitudes varying from 600 to 1500 km, and perigees generally near 260 to 280 km. Six of these are expected to reenter over the next half year 9 months. And the last debris pieces may not reenter before 2022-2023.
Yesterday it was 9 months ago that India conducted its first succesful Anti-Satellite (ASAT) test, destroying it's MICROSAT-R satellite on-orbit with a PDV Mark II missile fired from Abdul Kalam Island. I earlier wrote several blogposts about it, as well as an in-depth OSINT analysis in The Diplomat (in which I showed that the Indian narrative on how this test was conducted, can be questioned).
Over the past year, I have periodically written an update on the debris from this test remaining on orbit. In this post I again revisit the situation, nine months after the test.
A total of 125 larger debris fragments have been catalogued as well-tracked. Over 70 percent of these larger tracked debris pieces from the test were still on-orbit 45 days after the test (the moment they all should have been gone according to the Indian DRDO!).
Now, nine months after the test, 18 of these debris fragments, or 14 percent, are still on orbit. Their orbits are shown in red in the image in top of this post (the white orbit is that of the ISS, shown as reference).
In the diagram below, the number of objects per week reentering since the ASAT test is shown in blue. In grey, is a future prediction for the reentry of the remaining 14% of debris. The last pieces might linger untill mid-2023:
click to enlarge
click to enlarge
All but four of the remaining pieces currently have apogee altitudes well above the orbital altitude of the ISS, in the altitude range of many operational satellites. Nine of them have apogee altitudes above 1000 km, one of them up to 1760 km. Their perigees are all below ~280 km.
Part of that analysis was an assessment - also discussed in various previous posts on this blog - on how long debris from this ASAT test would stay on-orbit. Half-a-year after the test, it is time to make a tally of what is left and what is gone - and make a new estimate when the last piece will be gone.
A few more debris pieces have been catalogued by CSpOC since my last tally. As of 27 September 2019, orbits for 125 debris pieces from the ASAT test have been catalogued. Of these 125 objects, 87 (or 70%) had reentered or had likely reentered by 27 September, leaving 38 (or 30%) still on orbit.
click diagram to enlarge
click diagram to enlarge
Remember that the Indian DRDO had made the claim that all debris would
have reentered 45 days after the test. This is clearly not correct: of
the well-tracked debris for which we have orbits (presumably there is a
lot more for which we have no orbits), only 29%, i.e. barely one-third,
reentered within 45 days. Over 70% did not. At 120 days after the test, only half
of the catalogued population of larger debris had reentered.
click diagram to enlarge
click diagram to enlarge
I used SatEvo to produce reentry estimates for the 38 objects still on orbit on 27 September 2019. By the end of the year, some 15 to 16 of these larger debris fragments should still remain on-orbit.
One year after the test, at the end of March 2020, about 90% of all tracked debris should have reentered. The last or the tracked debris fragments for which we have orbits, might not reenter untill mid 2024.
The current apogee altitudes of the objects on-orbit spread between 270 and 1945 km. They have now well-dispersed in RAAN too, no longer sharing the same orbital plane:
click to enlarge
click to enlarge
Some 90% of the debris fragments still on-orbit have an apogee altitude above that of the ISS, meaning that they almost all have orbits that reach well into the orbital altitudes of operational satellites.
On 27 March 2019, India conducted it's first succesful Anti-Satellite (ASAT) test, destroying Microsat-R on orbit. I have blogged on this before here, here, here and here; and published a detailed OSINT analysis of this test in The Diplomat, in which I have shown that the Indian version of events concerning this ASAT test is not entirely correct.
So what is the current situation? The Indian government claimed right after the test that 45 days after the test, the space debris generated by the ASAT test would be gone. We are now a month after that deadline. Is everything gone indeed? Far from it.
Some 92 larger debris pieces resulting from the test have been catalogued by CSpOC. Of these, 56, i.e. some 60% were still on orbit 45 days after the ASAT test. And 46 (that is 50%) were still in orbit on June 15, one full month after all should have been gone according to the Indian Defence Research and Development Organisation (DRDO). These numbers are in line with my earlier forecast here.
The diagrams below visualize these data, including (grey lines) a new forecast for the remainder of the debris still orbiting. The top diagram is the cumulative percentage of reentered debris from the test, the lower diagram gives the number of objects reentering per week.
click diagram to enlarge
click diagram to enlarge
Many of these objects still on-orbit have
apogees still well into the range of operational satellites, i.e. they remain a threat to other objects in space. In my current
forecast for these remaining objects, at least 5 objects will stay in
orbit for at least a year to come, and the last one might not reenter
until mid-2021. So clearly, Indian DRDO estimates were much too
optimistic.
Summary - In this paper, I present an OSINT analysis of data available from Indian and US sources. From missile telemetry data visible in a DRDO released video (!) I reconstruct the last 2.7 seconds of the missile's trajectory relative to the trajectory of Microsat-R, showing that the missile hit the satellite under a clear upwards angle. I also discuss what can be gleaned from the orbital elements of the 84 debris pieces tracked so far.
The main conclusion is that the ASAT test was conducted in a less responsible way than originally claimed by the Indian government. First, the missile hit the target satellite on a clear upwards angle, rather than “head-on” as claimed by DRDO. Second and third, the test generated debris with much longer orbital lifetimes (up to 10 times longer), which ended up at much higher altitudes than the Indian government is willing to admit.
As much as 79 percent of the larger debris fragments tracked have apogee altitudes at or above the orbit of the International Space Station. Most of the tracked debris generated by the test orbits between 300 km and 900 km altitude, well into the range of typical orbital altitudes for satellites in Low Earth Orbit. As these debris fragments are in polar orbits, they are a potential threat to satellites in all orbital inclinations at these altitudes.This threat will persist for up to half a year (rather than the 45 days claimed by the Indian government), with a few fragments lingering on (much) longer, up to almost two years.
UPDATE, 2 May 2019:
On Twitter, I was asked to elucidate a bit more on how I did the analysis.
The delta V calculations have been done using equations from chapter 6 of "Space Mission Analysis and Design", third edition (Wetz and Larson (eds.), 1999).
The missile trajectory relative to the satellite trajectory was calculated with quite simple goniometry from the telemetry values (azimuth, range and elevation from the camera site) extracted from the DRDO video. Azimuth and range allow to calculate delta X, delta Y relative to the camera site on the flat reference plane. Elevation and range allow to calculate altitudes above the reference plane. AS the calculations are done with respect to a flat reference plane tangent to the earth surface at the camera location, this approach is sufficient. Earth curvature and true altitudes above the earth surface are irrelevant, a we are only interested in relative postions with regard to the satellite vector of movement.
Today the first 57 orbital element sets for Microsat-r debris, debris from the Indian ASAT test on March 27, appeared on CSpOC's data-portal Space-Track (I have posted on aspects of this Indian ASAT test earlier: here, here and here). They have catalogue numbers 44117 - 44173. The analysis below is based on these orbital element sets.The elements confirm what we already knew: that Microsat-r (2019-006A) was the target of the ASAT test.
The image above plots the orbit of the 57 debris fragments, in red. The white orbit is the orbit of the International Space Station ISS, as a reference. Below is a Gabbard diagram of the debris pieces, plotting their perigee and apogee values against their obital period. The grey dashed line gives the orbital altitude of the ISS, as a reference:
click diagram to enlarge
Again, it is well visible that a large number of the 57 fragments (80% actually) have apogee altitudes above the orbit of the ISS, well into the altitude range of operational satellites. This again shows (see an earlier post) that even low-altitude ASAT tests on orbiting objects, creates debris that reaches (much) higher altitudes. The highest apogee amongst the 57 debris pieces is that of 2019-006AR at 2248 km.
Below is the apogee altitude distribution as a bargraph (including a kernel density curve), again showing how pieces do reach the altitudes of operational satellites:
click diagram to enlarge
Most of the created debris in the current sample of tracked larger debris has apogee altitudes between 400 and 700 km. It is interesting to compare this to a similar diagram for debris from the 2008 US ASAT demonstration on USA 193, "Operation Burnt Frost":
click diagram to enlarge
The Operation Burnt Frost debris distribution peaked at a somewhat lower apogee altitude, ~250 km (the same orbital altitude as the target, USA 193) while the peak of the Indian ASAT debris apogee distribution is higher, ~400-500 km (there could however be detector bias involved here).
It is interesting to note that both distributions appear to be double-peaked, both having a secondary peak near 700-800 km. I remain cautious however, as that could be due to detector bias.
The question now is, how long this debris will survive. To gain some insight into the expected lifetimes, I used Alan Pickup's SatEvo software to make a reentry forecast for the debris fragments. It suggests that most of the debris will stay on orbit for several weeks to months: by half a year from now, most of it should be gone however, except for a few lingering pieces. Note that this forecast should be taken with some caution: it assumes a constant solar activity at the current level, and takes the NDOT values of the element sets face value.
The following bar diagram charts the forecast number of debris objects reentering per week (the x-axis being the number of weeks after the ASAT test) resulting from the SatEvo analysis:
click diagram to enlarge
Again, the result is quite similar to the actual lifetimes displayed by the USA 193 debris fragments after Operation Burnt Frost in 2008 (see an earlier post, with the same diagram), as expected:
So how big a threat is this Indian Anti-Satellite (ASAT) test of 27 March to operational satellites at higher altitudes, given that it was performed at relatively low altitude (283 km, see an earlier post)?
In an earlier post, I noted that the US ASAT demo on USA 193 ("Operation Burnt Frost") in February 2008 was a good analogue (read here why). Like the March 27 Indian ASAT test on Microsat-r, the USA 193 ASAT demonstration happened at relatively low altitude, even lower than the Indian test: 247 km. So where did debris from that test end up, altitude-wise?
The diagram above is a so-called "Gabbard Diagram" which plots apogee and perigee altitudes of individual debris fragments from the 2008 USA 193 intercept against their orbital period. (apogee is the highest point in its elliptical orbit, perigee the lowest point). The diagram can be of help to show insight into how high fragments are ejected in an ASAT test. Please do note that it concerns a subset of well-tracked larger fragments: most of the smaller fraction of debris, difficult or impossible to track, is absent from this sample.
As is visible in the diagram, many fragments ended up being ejected into highly eccentric ("elliptical") orbits with apogee, the highest point in their orbit, well above the intercept altitude. Many ended up with apogee altitudes well into the range of operational satellites (typically 400+ km).
I have indicated the International Space Station (ISS) orbital altitude (its current perigee altitude at ~407 km, not that of 2008) as a reference. Some 64% of the larger fragments in the pictured sample ended up with perigees apogees (well) above that of the ISS. Quite a number of them even breached 1000 km altitude.
This makes clear that even low altitude ASAT tests generate quite some debris fragments that can endanger satellites at higher altitudes. True, most of it reenters within hours to a few days of the test, but still plenty remain that do not. In my earlier post I showed the orbital lifetime of these same fragments from the USA 193 ASAT demonstration. Many survived on orbit for several weeks to months, occasionally even up to almost two years after the test:
click diagram to enlarge
So it is clear that a "harmless" low altitude ASAT test on an orbital object does not exist (note that I say orbital and not sub-orbital). Every test generates a threat to satellites at operational altitudes. Hence NASA administrator Bridenstine was quite right in his recent condemnation of the test. It is indeed very likely that debris fragments ended up in orbits with apogee at or above the orbital altitude of the ISS and other operational satellites in Low Earth Orbit.
