Tuesday 16 November 2021

The Russian Federation conducted a destructive ASAT test on Kosmos 1408 on November 15 [updated]

click map to enlarge

In the early morning of November 15, astronauts and kosmonauts onboard the ISS were instructed to put on their spacesuits and retreat to their Soyuz and Crew Dragon capsules. The reason was a close approach with a space debris swarm.

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)

 DNC 27.
    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)

 DNC 22.
    0200Z TO 0500Z DAILY 15 AND 17 NOV
    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.

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]

Thursday 11 November 2021

PAN/NEMESIS 1 is still drifting


click image to enlarge

In a blog post in September, I wrote that after almost eight years of being steady at longitude 47.7 E, the classified  SIGINT satellite PAN/NEMESIS 1 (2009-047A) had started to slowly drift eastwards, with the drift starting in February 2021.

Observations on the evening of November 8 show that it is still drifting. Currently it is near longitude 54.8 E, close to Yamal 402 and the grouplet GSAT 8, GSAT16 and GSAT 29, as is visible in the image above.

As it is drifting eastwards, it is getting lower in my sky: currently it is at 14.7 degrees elevation above my northeastern horizon.

The history of PAN's relocations so far (for backgrouds on PAN, its probable role and its frequent relocations during the first five years of its life, see my 2016 article in The Space Review):

click diagram to enlarge