Some first analytical results on the debris from the Russian ASAT test of 15 November 2021

 

click image to enlarge

 

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):

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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).

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One year after India's ASAT test

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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.

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Nine months after the Indian ASAT test: what is left?

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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.

At the time of the test, the Indian DRDO claimed that all debris would have reentered within 45 days after the test. As I pointed out shortly after the test in my blogpost here and in my article in The Diplomat, that was a very unrealistic estimate. This was underlined in the following months.

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:

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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.

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Six months after India's ASAT test

Six months ago today, on 27 March 2019 at 5:42:15 UT, India conducted its first successful Anti Satellite (ASAT) Test, under the code name Mission Shakti. I wrote an in-depth OSINT analysis of that test published in The Diplomat in April 2019.

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.

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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:

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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.

Two-and-a-half months after the Indian ASAT test: What's Up?

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.

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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.

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Why India's ASAT test was reckless (updated)

Today, I published a large article in The Diplomat:

"Why India’s ASAT Test Was Reckless. Publicly available data contradicts official Indian assertions about its first anti-satellite test"

The paper is online here: https://thediplomat.com/2019/05/why-indias-asat-test-was-reckless/

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.

First debris pieces from the Indian ASAT test of 27 March catalogued

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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:

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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:

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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":

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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.

Overall, the two distributions are similar, as I already expected.

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:

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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:

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Why even low altitude ASAT intercepts are a threat to operational satellites in higher orbits

Click diagram to enlarge. Orbital data from CSpOC

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:

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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.

An earlier, failed (?) ASAT test by India on 12 February 2019

image: DRDO

In my previous two posts (here and here), I analysed the much discussed Anti-Satellite (ASAT) test by India taking out Microsat-r on 27 March 2019.  Now the story gets a new twist.

Yesterday, Ankit Panda had a scoop in The Diplomat: it turns out that India attempted an ASAT intercept earlier, on February 12, 2019, which ostensibly failed according to US government sources.

Ankit is well sourced within the US Government, and his sources told him that a missile launch was observed on February 12th, which reportedly failed 30 seconds after lift-off.

A NOTAM and Area Warning had been given out for that day by the Indian government, for the "launch of an experimental flight vehicle" (the latter detail mentioned in the NOTAM but not the Maritime Area Warning). The Indian Government later published a bulletin omitting any reference to a missile failure, instead suggesting the succesful test of an "interceptor missile", launched from Abdul Kalam island, against an "electronic target".


 HYDROPAC 448/2019 (63,71)
(Cancelled by HYDROPAC 485/2019)

BAY OF BENGAL.
NORTHERN INDIAN OCEAN.
INDIA.
DNC 03.
1. HAZARDOUS OPERATIONS 0515Z TO 0645Z DAILY
   12 AND 14 FEB IN AREA BOUND BY
   20-48.07N 087-02.23E, 18-07.27N 086-25.02E,
   01-46.62N 087-30.51E, 02-57.91N 093-50.49E,
   18-33.79N 088-46.21E, 20-48.95N 087-06.99E.
2. CANCEL THIS MSG 140745Z FEB 19.

( 080903Z FEB 2019 )


The hazard area from the Area Warning for Feb 12 is very similar to that of the March 27th ASAT test. Compare these two maps, for February 12 and March 27 (the track shown is the groundtrack of Microsat-r, the target of the March 27 ASAT test. The blue and red areas indicated, are the hazard areas from the Area Warnings):

February 12 Area warning and Microsat-r track

March 27 Area Warning and Microsat-r track.

The hazard areas are virtually indistinguishable, and so is the location of the Microsat-r ground track. Microsat-r clearly was the target ("electronic" or not) of the February 12 attempt as well. Even the pass times are close for both dates: compared to March 27, the Microsat-r pass over Abdul Kalam happend about 1 minute earlier on Feb 12. With the benefit of hindsight, it is all very clear.

Indeed, press reports based on the mentioned Indian Government bulletin give 11:10 am Indian Standard Time (05:40 UT) as the time for the Feb 12 attempt. From the listed time, we can deduce that the virtual intercept would have happend at 271 km altitude, some 12 km lower than the 283 km altitude of the succesful March 27 intercept.

Microsat-r was in a slightly different orbit on February 12th: a slightly more eccentric, but stable 240 x 300 km orbit. During the succesful ASAT test of March 27, Microsat-r was in a slightly more circular 260 x 285 km orbit.

click diagram to enlarge

An open question is whether the February 12 attempt was a rehearsal and not a real attempt to hit and kill the satellite; or if it was a real attempt but failed. If Ankit Panda's US government sources are correct that the missile failed 30 seconds after lift-off, it would seem a failure, unless the cut-off after 30 seconds was intentional. Another open question is whether the US government was aware on February 12 that it was an ASAT test (see also this Twitter thread by Brian Weeden).

With the February 12th attempt so soon after launch of Microsat-r (January 24th), it would appear that Microsat-r was specifically launched to function as an ASAT target.

Debris from India's ASAT test: how long until it is gone?

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After India's ASAT test on 27 March 2019, on which I wrote in detail in my previous post, many people asked the obvious question related to the debris threat from this test: how long would debris pieces stay on-orbit?

At the moment of writing (late 31 March 2019), no orbits for debris pieces have been published yet, although CSpOC has said they are tracking some 250 pieces of debris currently.

Some insight into the possible lifetimes of debris fragments can however be gleaned from the debris generated by "Operation Burnt Frost", the destruction with an SM-3 missile of the malfunctioned USA 193 satellite by the United States of America on 21 February 2008.

The USA 193 ASAT demonstration in 2008 provides a reasonably good analogue for the Indian ASAT test on Microsat-r on March 27. The orbital altitudes are somewhat comparable: USA 193 moved in a ~245 x 255 km orbit and was intercepted at ~247 km altitude. Microsat-r moved in a ~260 x 285 km orbit and was intercepted at 283 km altitude, i.e. a difference of ~36 km in altitude compared to USA 193. Both intercepts happened in years with low solar activity, i.e. similar upper atmospheric conditions. There are some differences too: USA 193 was intercepted near perigee of its orbit, Microsat-r near apogee. There is a difference in orbital inclination as well: 58.5 degrees for USA 193, and a 96.6 degree inclined polar orbit for Microsat-r. Nevertheless, the USA 193 intercept is a good analogue: much more so than the Chinese Fengyun-1C ASAT in 2007, which was at a much higher altitude and yielded much longer lived debris fragments as a result.

CSpOC has orbital data available for 174 debris fragments from USA 193. I mapped the decay dates of these fragments and constructed this diagram. The x-axis of the diagram shows you the number of weeks after the destruction of USA 193, and the bars show you how many fragments reentered that week:

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The distribution of reentry dates shows that most fragments reentered within two months, with a peak about 3 weeks after the destruction of USA 193. Almost all of it was gone within half a year. Yet, a few fragments ejected into higher orbits had much longer orbital lifetimes, up to almost two years. This shows that even low altitude ASAT tests on objects in Earth orbit do create at least a few fragments with longer orbital lifetimes.

The 174 debris fragments in question constitute a subset of larger, well-tracked particles within the USA 193 debris population. There were thousands more fragments, most very small, that were not (well) detected. Most of these likely reentered within hours to a few days after the destruction of  USA 193, given that small fragments have a large area-to-mass ratio (meaning their orbits decay faster, as they are more sensitive to drag).

Given the similarities, we can expect a similar pattern as the diagram above for debris fragments from the Indian ASAT test. As the Indian intercept occured slightly (about 35 km) higher, fragments might perhaps last a little bit - but probably not that much - longer.


UPDATE (2 April 2019):
A follow-on post with an analysis or orbital altitudes of generated debris can be read here.

India's surprise ASAT test of 27 March 2019 (updated)

Click to enlarge. Reconstruction made with STK.

The Indian Prime Minister Narendra Modi made a surprise announcement in the morning of 27 March 2019, claiming that India conducted an anti-satellite (ASAT) test that night under the codename "Mission Shakti".

In the hours after the announcement, some sparse details appeared in Government statements and the Indian press: these included that the launch of the interceptor took place from Abdul Kalam island on the Indian East Coast, and the target was intercepted at an altitude of ~300 km. The missile used was a three-staged missile with two solid fuel boosters. The target satellite was not identified, other than that it was an Indian satellite.

T.S. Kelso, @Dutchspace on twitter and myself were however able to identify the target as being likely Microsat-r (2019-006A), a 740 kg Indian military satellite launched two months earlier, on 24 January 2019, on PLSV-C44 from Satish Dhawan Space Centre. We were also able to determine that the test must have happened near 5:40 UT (27 March 2019).

There are only two Indian satellites that fit an orbital altitude of ~300 km: Microsat-r (2019-006A) and Microsat-TD (2018-004T). Of these, Microsat-r was in a very low orbit (roughly 260 x 285 km). It would also pass right over Abdul Kalam island around 5:42 UT on 27 March 2019.

A Maritime Area Warning for "Hazardous operations" was given out before the test, which in hindsight is likely related to the test:


HYDROPAC 955/19

 NORTHERN INDIAN OCEAN.
 BAY OF BENGAL.
 INDIA.
 DNC 03.
 1. HAZARDOUS OPERATIONS 0430Z TO 0830Z DAILY
 27 AND 30 MAR IN AREA BOUND BY
 20-48.06N 087-02.24E, 18-07.27N 086-25.03E,
 01-46.62N 087-30.52E, 02-57.91N 093-50.49E,
 18-33.79N 088-46.21E, 20-48.95N 087-06.99E.
 2. CANCEL THIS MSG 300930Z MAR 19.//

 Authority: NAVAREA VIII 248/19 221002Z MAR 19.

 Date: 222130Z MAR 19
 Cancel: 30093000 Mar 19


Plotted on a map, it defines an elongated conical hazard area with the tip at Abdul Kalam island. The hazard area fits an object in a polar orbit. Moreover, it exactly fits the track of Microsat-r:

click map to enlarge

click map to enlarge

The fit shows that the intercept might have occured near 5:40 UT, give or take a few minutes, at 283 km altitude while Microsat-r was northbound moving towards Abdul Kalam island. The fit to the hazard area is excellent.

Microsat-r was launched by PLSV-C44 on 24 January 2019, ostensibly as a military earth observation satellite. The satellite was initially in a 240 x 300 km orbit but manoeuvered into a more circular, less eccentric ~260 x 285 km late February.

PLSV-C44 (including Microsat-r) launch. Photo: ISRO

click illustration to enlarge

click diagram to enlarge

click diagram to enlarge

With this ASAT test, India joins a very small number of countries who have shown to have ASAT capabilities: the USA, Russia, and China. The test will certainly cause uneasiness with several countries and provoke diplomatic reactions and condemnation. This is technology many countries do not like to see proliferate, and testing ASAT weapons in space is widely seen as irresponsible, because of the large number of debris particles it generates on orbit, debris that can be a threat to other satellites. Our modern society is highly reliant on satellite technologies, so any threat to satellites (either from ASAT test debris, or by deliberate ASAT targetting) is a serious threat.

In this case, because of the low altitude of the target satellite, the debris threat will be limited (but not zero). Few satellites orbit at this altitude (the ISS for example orbits over 100 km higher). The vast majority of debris generated will quickly reenter into the earth atmosphere, most of it within only a few weeks. But previous ASAT tests like the Chinese Fengyun 1C intercept in 2007 and the USA's response to that, "Operation Burnt Frost" destroying the malfunctioned spy satellite USA 193 in 2008, have shown that a few debris pieces will be ejected into higher orbits, so even at this low altitude the danger of such a test is not zero. Nevertheless, the Indian government seems to have learned from the outcry following China's 2007 test, and they specifically point out the lower altitude of their intercept target, and the lower risk stemming from that.

As to the "why" of the test, there are several answers, some of which can be read in this excellent twitter thread by Brian Weeden. One reason is military posturing towards China. Another one, as Brian points out, is the current emerging call to restrict ASAT tests: India perhaps wanted to have a test in before these calls result in international treaties prohibiting them. Last but not least, the test could perhaps also be a first step towards an anti-ballistic missile system. [edit 30 Mar 2019: ] India already tested an anti-ballistic missile system before, and this can be seen as a next step in building such a  missile defense system.


UPDATE 30 March 2019:

In the press, on twitter and in a message on the Space-Track portal, CSpOC has indicated it is now tracking more than 250 debris pieces from the ASAT test. So far, no orbital elements for debris pieces have been released however.

#JFSCC, via #18SPCS, is actively tracking more than 250 pieces of debris associated with Indian ASAT launch that occurred at 0539 UTC Mar 27, and issuing conjunction notifications to satellite operators as needed to support
spaceflight safety.

— 18 SPCS (@18SPCS) March 29, 2019

They also confirm the time of the test as 5:39 UT. In this article, it is indicated that the launch and intercept was detected by US Early Warning satellites, i.e. the SBIRS system of infrared satellites that has been discussed several times previously on this blog.

clickimage to enlarge

click to enlarge

05:39 UT corresponds to the time the satellite first appears over the horizon as seen from the interceptor launch site at Abdul Kalam island: theoretical appearance over the horizon as seen from that site was at 05:38:38 UT.

So I assume the 05:39 UT time corresponds to the moment the interceptor was launched after first detection of the target (assuming a detecting radar located on the launch site), at a range of 8700 km. Indian sources say the intercept, from launch to impact, took 3 minutes. This would place the actual intercept at ~05:42 UT, near 17.68 N, 87.65 E, at an altitude of ~283.5 km and a range of ~450 km from the launch site.

Click to enlarge. Reconstruction made with STK.

The interceptor was a three-staged missile with a kinetic kill vehicle, i.e. a kill vehicle that smashes into the satellite, destroying it by the force of impact. The Indian Dept. of Defense released this image of the launch of the interceptor:

click image to enlarge

Note (31 March 2019): a follow up post discussing likely orbital lifetimes of fragments created, can be read here.

Note 2 (2 April 2019): a second follow up post discussing an earlier failed attempt on February 12, can be read here.