Thread by @Marco_Langbroek

1/24
In this thread, a summary of my OSINT analysis of a DRDO video of the Mar 27 Indian #ASAT test. I will show that the kill vehicle hit #Microsat-r in an upwards direction, not "head on" as the DRDO claims.
@ssc_nl @nktpnd @brianweeden @wslafoy @planet4589 @Genevaexpat

2/24
The Indian DRDO released a video documentary on #MissionShakti. Part of this video is imagery from an earth-based IR camera, that shows the missile hit and destroy Microsat-r:

3/24
The video gives us an accurate time of the intercept (5:42:15.5 UT), and from that a position, but interestingly enough the frames also contain missile telemetry (range, azimuth and elevation)! They cover the final 2.7 seconds of the missile trajectory.

4/24
I first thought the range and azimuth data concerned the satellite (and for the impact moment it by definition does), but after noting the range data went up instead of down, it was clear that these data actually concern telemetry from the missile (!).

5/24
And what is more: these telemetry data provide proof that the missile did *not* hit the target satellite "head-on", i.e. contradicting what DRDO chairman Sateehs is claiming here:

6/24
From the azimuth, range and elevation listed in the video frame showing the impact moment, I could determine where the IR camera that filmed the sequence was approximately located (accurate to +- 1 km). This location is some 15 km SW of Chandipur ITR.

7/24
Knowing that position, the telemetry data (azimuth, elevation and range) from the other video frames can then be used to map the missile location, and in doing so reconstruct the final part of the missile trajectory!

8/24
The positions I report here are Cartesian positions with reference to a flat plane through the camera location, tangent to the earth surface. This avoids having to bother about earth curvature, as we are only interested in positions relative to the satellite vector.

9/24
Hence, it is important to realise that altitudes in the diagrams below, are *not* altitudes with respect to Mean Sea Level or the WGS84 geoid: but altitudes (in km) above this flat reference plane. These are lower than the MSL altitudes (how much, depends on the range)!

10/24
From azimuth, elevation and range information extracted from the video frames, I calculated delta X, delta Y distances relative to the IR camera sensor location, as well as the altitude Z above the flat reference plane.
From the orbital data, I did the same for Microsat-r.

11/24
Here is the result in the horizontal plane (i.e. seen from "above"). X points east, and Y points north.
Here it indeed looks like an almost frontal "head-on" hit (in fact it comes slightly from the west under a very small horizontal angle).
BUT..... (drumroll....)

12/24
....But: in the vertical plane (i.e. seen from the side), the situation is quite different! The trajectory then clearly is *not* head-on, in this plane. It is in an oblique, notably upwards direction, under an angle of ~135 degrees with the satellite movement vector:

13/24
In other words: the Indian claim of a "head-on" hit minimizing the risk of debris ejected to higher altitudes, rather than upwards hit, seems to be contradicted by the telemetry data in the video they themselve released.

14/24
(note that TLE's, the orbital elements of Microsat-r, have an intrinsic uncertainty in position of about 1 km. This is indicated by the gray area around the nominal positions for the satellite. Within the error margin, the missile and satellite trajectories meet).

15/24
Interestingly, as part of that DRDO video there is an animation which also shows a non head-on impact. Here is a still:

16/24
The same video also has footage of the targetting IR camera on the missile itself. In the last frames, it shows the outline of the satellite including solar panels. These appear to be seen almost full-on, which again speaks against a "head-on" hit:

17/24
Because: a head-on hit would show the solar panels edge on, given the relative position of the sun at that moment and the fact that solar panels usually face the sun. An oblique hit would show them more full-on, as in the video. Compare:

18/24
So multiple lines of evidence point to it having not been a head-on hit, but an upwards moving oblique hit instead.

19/24
As we know the camera position, we can also reconstruct the projected satellite's trajectory in the impact footage FOV. Here it is projected on one of the frames (movement is upwards). Note how the debris cloud is oriented along the movement vector of the satellite:

20/24
The telemetry from the DRDO video, shows that in the Cartesian XY plane, the kill vehicle hit it under a very slight angle with the satellite movement vector (crossing the satellite path coming from slightly east and then homing in slightly from the west).

21/24
That same thing is borne out by the distribution of the orbital inclinations of the debris fragments that are being tracked by CSpOC. These fragments have somewhat lower orbital inclinations than the satellite's original orbit, meaning an impact coming slightly from west:

22/24
Finally, using tracking data from CSpOC on these debris fragments, I calculated the delta V (the extra ejection speed relative to the original Microsat-r speed) necessary to get them into these orbits, taking into account changed orbital altitudes & the inclination change.

23/24
The resulting delta V's have this distribution, with most of it in the 10 to 300 meter/second range:

24/24
That's it, as far as the current state of my OSINT analysis is concerned. As said, I will write this up more comprehensively as a more formal publication, but that might take a few days.