Raiders of the Lost Venus Probe: a post-mortem of an interesting reentry and the confusion it left

On 10 May 2025, an unusual object, the Kosmos 482 Descent Craft, had an uncontrolled reentry (see this earlier post).

With my TU Delft colleague Dominic Dirkx, I have written a 'post mortem' for this reentry for The Space Review of 27 May 2025, titled:

 "Raiders of the Lost Venus Probe: a post-mortem of an interesting reentry and the confusion it left"

It can be read here.

(the Tudat script we used for our reentry analysis can be downloaded here. Tudat itself can be downloaded here). 

Kosmos 482 Descent Craft reentry forecasts [PERIODICALLY UPDATED]

Click diagram to enlarge

Last update: 11 May 2025 10:15 UTC 

 

(this post is being periodically updated with new reentry forecasts/postcasts)

 

* The last Tudat nominal forecast is reentry on 10 May 2025, 6:39 UTC ± 1.5 hr *

* The Tudat nominal aftercast is reentry on 10 May 2025, 6:40 UTC ± 1.5 hr *

 

 

 

In the second week of May 2025, an unusual object reentered. It concerns the Kosmos 482 Descent Craft (1972-023E, cat. nr. 6073).

This object is the lander module from a 1972 failed Soviet Venera mission to Venus. Because of a failure of the upper stage of the rocket that launched it, it got stuck in a very elliptical orbit around Earth in 1972, instead of going to Venus. 

 

I published an extensive discussion and analysis of this object and its history three years ago in The Space Review. The identification of this object as the lander module was initially suggested by Jonathan McDowell (see his brief interesting history here).

Recently declassified Russian historic documents unearthed by Anatoly Zak point out that after failure to get to a heliocentric orbit, the lander was deliberately separated from the main bus by the spacecraft operators. My analysis published in 2022 suggests that this happened in June 1972. The lander is encased in a semi-spherical shaped Titanium protective shell, a kind of rounded metal bucket so you will (see image below).

As this is a lander that was designed to survive passage through the Venus atmosphere, it is possible that it will survive reentry through the Earth atmosphere intact, and impact intact. It likely will be a hard impact: I doubt the parachute deployment system will still work after 53 years and with dead batteries. There are many uncertain factors in whether the lander will survive reentry though, including that this will be a long shallow reentry trajectory, and the age of the object.

 

 

Venera 7 lander mock-up. The Kosmos 482 Descent Craft is probably similar. Photo: NASA

 

The risks involved are not particularly high, but not zero: with a mass of just under 500 kg and 1-meter size, risks are somewhat similar to that of a meteorite impact. A Tudat reentry analysis to ground level suggests an impact speed (after atmospheric deceleration) of about  65-70 meter per second (~242 km/h), assuming the reentering lander did not break up or extensively ablate during reentry (see the diagram below: note the logarithmic scale of the x-axis). The kinetic energy at impact is similar to that of a 40-55 cm large (after ablation) meteorite fragment. As it will likely reach earth surface as only one single object, the risks involved are lower than for example those created by a Falcon 9 upper stage reentry, which showers multiple meter-sized objects over a large area (as we saw recently with the impact of Falcon 9 remains in Poland).

 

Click diagram to enlarge

 

The diagrams below shows the change in altitude of apogee and perigee over the past 1.5 years and the past 4 months: notably apogee has been coming down steadily, but in the past few months, perigee has started to come down too. Early May 10 around 00:35 UTC, the object was in a 166 x 120 km orbit, with apogee coming down by 70 km/day and perigee by 25 km/day (and these values increasing each day, see diagram below).

 

Click diagram to enlarge

 

Click diagrams to enlarge

 

The reentry is an uncontrolled reentry. Even close to reeentry, we cannot say with any degree of certainty when and where the Kosmos 482 Descent Craft exactly will reenter.

With an orbital inclination of 51.95 degrees [note: I initially erroneously stated 51.7 here], the reentry can occur  between latitude 52 N and 52 S.

Over the past months, together with my colleague Dominic Dirkx,  we have been developing a reentry model for this object in Tudat.

 

Tudat, the TU Delft Astrodynamics Toolbox is open source, multi-platform Astrodynamics software developed and maintained at the Aerospace faculty of Delft University of Technology (TU Delft) in the Netherlands (where I work). The Tudat script we use for our analysis is here, while the Tudat software itself is available here.

 

The Kosmos 482 Descent Craft is probably similar to the descent craft of Venera 8 (which was launched only a few days earlier in 1972). Literature values suggest that the object is about 1 meter in size and semi-spherical, with a mass of ~495 kg. 

 

Using our Tudat model and a 1-meter diameter, and the NRLMSISE00 model atmosphere with historic space weather data, we find that the orbital evolution of  the object from mid-1972 to early 2025 is actually best matched when we use a mass of 480 kg, 15 kg less than the literature value. All our forecast predictions are therefore done using a mass of 480 kg. 

 

For our forecasts we employ the NRLMSISE00 model atmosphere, and historic spaceweather data plus estimated future space weather (solar flux). Orbit updates for each run are sourced from the US Military tracking network CSpOC (so as a note: our forecasts are not based on our own tracking data. They are based on our own custom reentry model developed at Delft University of Technology, with external tracking data from CSpOC as input).

 

Click diagram to enlarge

The diagrams in top of this post and below (which I will periodically update) give the evolution of our reentry predictions, based on orbits issued for the object since November 2024. Over the past half year, the model has consistently pointed to reentry within a few days of 9-10 May 2025. 

 

The latest nominal forecasts currently center on early May 10, but are still fluctuating with each orbital update. Early May, there was a short-lived tendency in the model runs of a shift towards a later time of reentry (i.e. May 11 rather than May 10), as can be seen in the below diagrams and the table near the end of this post. But lately, the new forecast runs have been returning to nominally May 10. 

 

 

Click diagram to enlarge

 

Click diagram to enlarge

 

The brief shift towards a later date in the early May model runs was due to space weather forecasts underestimating future solar activity at that time. I had started to note this (when comparing earlier forecast solar flux values to actual solar flux values for the last days of April  and the first days of May) and already expected the nominal forecasts to return to May 10, as they now indeed have done.

 

This highlights the influence of uncertainties in estimated future solar activity on the forecasts. Future solar activity is not well predictable. Even the best reentry models will be off in their forecast if actual solar activity in the window between the moment of forecast and the moment of reentry develops differently than the predictions. Solar flux variations are an important driving factor of short-term variations in density and extent of the upper atmosphere. The latter determine how many drag the object experiences over its orbit, and with that how quick the orbit decays. Stronger solar activity will mean an earlier reentry, lower solar activity a later reentry.

 

Of course, at this point the uncertainty in the forecast is still +/- 1.5 hours. Yet, the uncertainty window has now decreased to the point that we can rule out certain parts of the world: Africa is safe. So is Japan, East Asia, and the USA.

 

The map below gives the trajectory of the object over the current uncertainty window of the Tudat reentry forecast (red dots are cities with over 1 million inhabitants, between latitude 52 N and 52 S). In our model the spacecraft could have reentered anywhere along the blue line:

 

Click map to enlarge

 

 

CSpOC, the US military tracking network, has started to provide TIP (Time of Impact Prediction) messages for the object since May 6. They are depicted as red circles in the diagram earlier in this post.

 

The last orbit update published by CSpOC has epoch 10 May 2025, 00:36 UTC, i.e. dates from about 6 hours before the time we think it actually reentered. There are later radar detections from Europe, per ESA, dating to as late as 6:04 UTC, but no orbit based on that has been published.

A roundup of current reentry forecasts from various sources (each running their own reentry model) compiled 10 May 15:30 UTC:

 

Tudat forecast:              10 May   06:39 ± 91  min UTC

Tudat postcast:              10 May   06:40 ± 91  min UTC

Aerospace Corp forecast:     10 May   06:29 ± 120 min UTC

RosCosmos postcast:          10 May   06:24 ± ?   min UTC

ESA postcast:                10 May   06:16 ± 22  min UTC

EU-SST forecast:             10 May   06:04 ± 20  min UTC

CSpOC TIP postcast:          10 May   05:32 ± 12  min UTC *

 

* this cannot be correct given that a positive radar detection from Germany at 6:04 UTC was reported by ESA.

 

note: forecast = issued before the reentry; postcast = issued after the reentry after re-analysis.

 

ESA reports that they had a positive radar detection of the spacecraft, still on-orbit, at 6:04 UTC while it was passing over Germany (presumably with the TIRA radar); and a negative detection one orbital revolution later, at 7:32 UTC. This implies reentry during the window 6:04 - 7:32 UTC. Five of the forecasts fall in that window: our Tudat forecast, and those by RosCosmos, ESA, the Aerospace Corporation, and also EU-SST when taking the error margins on the latter into account.

 

Roscosmos, the Russian Space Agency, on Telegram states reentry at "6:24 UTC" over the Indian Ocean. That is not too far (15 minutes) from our latest TUDAT model results. Three remarks: (1) this is not a reentry detection but likely another model result (just as the others), based on an earlier groundbased detection during a pass over presumably southern Russia. (2) It does not come with a stated uncertainty window: is that 10 minutes, 30 minutes, an hour? (3) It remains a question how serious one should take Russian State statements these days as sometimes pragmatic considerations (such as deliberate denial of responsibility or risk) are leading. 

 

While many news media seem to treat the RosCosmos announcement as 'authoritive' and the 'most accurate' or 'final' say on the matter, there is in reality no clear reason to do so. It is not clear at all whether the RosCosmos position is more accurate than the other model estimates, and how meaningful the stated positions and time are given the lack of error margin information.

A final accurate TIP from CSpOC has not yet appeared (and might not appear if they have no space-based detections of the reentry fireball). CSpOC sometimes, several hours to a day after a reentry, publishes a very accurate (with quoted +- 1 minute uncertainty) final TIP which Jonathan McDowell and I believe is not based on a reentry model, but on space-based (SBIRS satellite) detections of the reentry fireball, hence the accuracy. They have not issued such a TIP so far for this reentry, unfortunately. Note that their last issued TIP cannot be correct, given the reported positive radar detection of the spacecraft passing over Germany at 6:04 UTC.

 

This is how the nominal reentry points have been placed by various organisations, each based on their own modelling:

 

Click map to enlarge

 

It is clear that the assessments spread. Ignoring the clearly incorrect CSpOC TIP, the other models all suggest reentry over either southwest Asia or the Indian Ocean. My verdict is that the latter area is the most likely place.

 

Below is the evolution of the reentry forecast from our TU Delft Tudat model in tabular form, latest forecast at the bottom. Please take note of the uncertainty values listed in the last column!

 

The 'postcast' value is a re-run of the model after-the-fact based on the last published orbit and the actual rather than estimated space weather of May 10.

 

--------------------------------------------------------------------
TUDAT REENTRY FORECAST EVOLUTION for KOSMOS 482 Descent Craft
M. Langbroek & D. Dirkx, Delft University of Technology

Date/times in UTC

REFERENCE ORBIT    ORBIT EPOCH      REENTRY FORECAST   +/-   
----------------------------------------------------------------
15-11-2024 05:43   24320.23870400   05-05-2025 23:33   42.9 days   
01-12-2024 05:32   24336.23116452   08-05-2025 09:09   39.5 days   
15-12-2024 18:58   24350.79080401   07-05-2025 11:51   35.7 days   
01-01-2025 11:20   25001.47260254   09-05-2025 07:20   32.0 days   
15-01-2025 03:23   25015.14140884   10-05-2025 20:40   28.9 days   
02-02-2025 08:54   25033.37115746   13-05-2025 17:52   25.1 days   
15-02-2025 03:20   25046.13941015   11-05-2025 09:52   21.3 days   
01-03-2025 00:07   25060.00535989   10-05-2025 17:51   17.7 days   
15-03-2025 05:56   25074.24770046   10-05-2025 07:57   14.0 days   
30-03-2025 12:05   25089.50360681   09-05-2025 21:11   10.1 days   
13-04-2025 21:32   25103.89775709   09-05-2025 22:01    6.5 days   
20-04-2025 01:39   25110.06916305   09-05-2025 11:31    4.9 days   
22-04-2025 21:24   25112.89204293   09-05-2025 12:48    4.2 days   
23-04-2025 22:57   25113.95657237   09-05-2025 19:43    4.0 days   
27-04-2025 00:27   25117.01893077   10-05-2025 04:52    3.3 days   
28-04-2025 00:24   25118.01685903   10-05-2025 06:33    3.1 days   
28-04-2025 22:50   25118.95143786   10-05-2025 06:01    2.8 days   
01-05-2025 20:57   25121.87323063   10-05-2025 14:30    2.2 days   
02-05-2025 09:12   25122.38386703   11-05-2025 02:36    2.2 days   
02-05-2025 12:16   25122.51167762   11-05-2025 03:41    2.2 days   
02-05-2025 17:52   25122.74476620   11-05-2025 06:50    2.1 days   
03-05-2025 18:07   25123.75533175   10-05-2025 20:48    1.8 days   
03-05-2025 21:05   25123.87876286   10-05-2025 23:06    1.8 days   
04-05-2025 20:47   25124.86648285   10-05-2025 19:05    1.5 days   
05-05-2025 20:29   25125.85361170   10-05-2025 07:26    1.1 days   
06-05-2025 09:39   25126.40254557   10-05-2025 08:37    1.0 day
06-05-2025 21:26   25126.89335737   10-05-2025 07:51   20.6 hr
07-05-2025 21:00   25127.87559184   10-05-2025 07:34   14.6 hr
08-05-2025 11:31   25128.48053679   10-05-2025 07:24   11.0 hr
08-05-2025 13:13   25128.55136979   10-05-2025 07:34   10.6 hr
08-05-2025 19:13   25128.80083450   10-05-2025 07:54    9.2 hr
09-05-2025 12:37   25129.52575525   10-05-2025 06:23    4.4 hr
09-05-2025 14:12   25129.59226104   10-05-2025 06:30    4.1 hr
09-05-2025 15:43   25129.65543839   10-05-2025 06:35    3.7 hr
09-05-2025 19:55   25129.82989846   10-05-2025 06:34    2.7 hr
10-05-2025 00:35   25130.02495443   10-05-2025 06:39    1.5 hr

                               nominal location 35.7 S 126.5 E

POSTCAST:

10-05-2025 00:35   25130.02495443   10-05-2025 06:40    1.5 hr

                               nominal location 38.0 S 129.8 E

 

I will periodically update this table with new forecasts, more frequently so when the reentry dates comes nearer.

Here is footage I shot of the Kosmos 482 Descent Craft with my tracking camera in Leiden, in 2020:

An added note: about that parachute....

To muddy the waters further, a story is spreading that the parachute of the landing craft might already have deployed in space. This is based on telescopic imagery purportedly showing this.

I have strong doubts that the imagery in question shows any meaningful detail. The imagery has the same origin, and the same problems attached, as the imagery I discussed in 2022 in my Space Review article. I think the "detail" is the result of camera/telescope shake and atmospheric distortion.

 

UPDATE 28 May 2025:
With my colleague Dominic Dirkx, I wrote a 'post mortem' on the reentry for The Space Review that can be read here.

This post has been updated with new forecasts and additional background information several times

A Chinese FOBS surprise (and other stuff of nightmares) [UPDATED]

 

[this post was updated on October 18 to reflect new information and a refutal of the claim by the Chinese Government. It was again updated on October 21 to reflect new information, including claims that it concerned *two* tests, on July 27 and August 13]

If you want to have nightmares for days, then listen to Jeffrey Lewis menacingly whispering "fòòòòòòòòòòbs..." in the first few seconds of this October 7 episode of the Arms Control Wonk Podcast...

I bet some people connected to US Missile Defense hear this whisper in their sleep currently, given news that broke yesterday about an alledged Chinese FOBS test in August.

FOBS (Fractional Orbital Bombardment System) has menacingly been lurking in the background for a while. In the earlier mentioned podcast it was brought up in the context of discussing new pictures from North Korea showing various missile systems: including a new one which looks like a hypersonic glide vehicle on top of an ICBM (which is not FOBS, but FOBS was brought up later in the podcasts as another potential future exotic goal for the North Korean missile test program).

image: Rodong Sinmun/KCNA

But the days of FOBS being something exclusively lurking as a menace in the overstressed minds of Arms Control Wonks like Jeffrey are over: the whole of Missile Twitter is currently abuzz about it.

The reason? Yesterday (16 Oct 2021) the Financial Times dropped a bombshell in an article, based on undisclosed intelligence sources, that claims China did a test in August with a system that, given the description, seems to combine FOBS with a hypersonic glide vehicle. [edit: but see update at end of this post]

That last element is still odd to me, and to be honest I wonder whether things have gotten mixed up here: e.g., a mix-up with a reported Chinese suborbital test flight of an experimental space plane from Jiuquan on 16 July this year. [edit: and this might be right, see update at the end of this post]

Anyhow: the FT claims that China:

"tested a nuclear-capable hypersonic missile in August that circled the globe before speeding towards its target".

"Circled the globe" before reaching it's target: that is FOBS.

 

FOBS

So, for those still in the dark: what is FOBS?

FOBS stands for Fractional Orbital Bombardment System. Unlike an ICBM, which is launched on a ballistic trajectory on the principle of "what goes up must come down", FOBS actually brings a nuclear payload in orbit around the earth, like a satellite.  

For example, a very Low Earth Orbit at an orbital altitude of 150 km, which is enough to last a few revolutions around the earth. At some point in this orbit, a retrorocket is fired that causes the warhead to deorbit, and hit a target on earth.

FOBS was developed as an alternative to ICBM's by the Soviet Union in the late 1960-ies, as a ways to evade the growing US Early Warning radar system over the Arctic. Soviet ICBM's would be fired over the Arctic and picked up by these radar systems (triggering countermeasures even before the warheads hit target). But FOBS allowed the Soviet Union to evade this by attacking from unforseen directions: for example by a trajectory over the Antarctic, which would mean approaching the US from the south, totally evading the Early Warning radars deployed in the Arctic region.

In addition, because FOBS flies a low orbital trajectory (say at 150 km altitude), whereas ICBM's fly a ballistic trajectory with a much higher apogee (typically 1200 km), even when a conventional trajectory over the North Pole would be used, the US radars would pick up the FOBS relatively late, drastically lowering warning times (the actual flight times of an ICBM and a FOBS over a northern Arctic trajectory are not much different: ~30 minutes. Over the Antarctic takes FOBS over an hour. But of relevance here is when the missiles would be picked up by US warning radars).

The Soviet Union fielded operational FOBS during the 1970-ies, but eventually abandoned them because new western Early Warning systems made them obsolete. This notably concerned the construction of an Early Warning system in space, consisting of satellites that continuously scan the globe for the heat signatures of missile launches. DSP (Defense Support Program) was the first of such systems: the current incarnation is a follow-up system called SBIRS (Space-Based Infra-Red System). This eliminated the surprise attack angle of FOBS, because their launches would instantly be detected..

 

Reenter FOBS

But now China has revived the idea, moreover with an alledged test of an actual new FOBS system (while Russia also has indicated they are looking into FOBS again). From the description in the Financial Times, which is based on undisclosed intelligence sources, the Chinese FOBS system moreover includes a hypersonic gliding phase. [edit: but see update at the end of this post]

Initially this surprised me: I was of the opinion (and quarrelled with Jeffrey Lewis about this, but am man enough to now admit I was wrong and he was right. Sorry Jeffrey, I bow in deep reverance...)  that FOBS in 2021 had very little over regular ICBM technology and was therefore a very unlikely strategy, feasible only as a desperate last defensive act of revenge before total annihilation in case of an attack by others. Because using FOBS in an offensive tactical role would guarantee you to lead to Mutually Assured Destruction.

I still stand behind that last part, but clearly, China thinks they nevertheless need FOBS. Why?

FOBS still has one advantage over regular ICBM's. That is, that a southern trajectory over Antarctica approaching the US mainland from the south, while not going undetected by SBIRS, still avoids warhead intercepts by the US anti-Ballistic Missile Defense (BMD) systems, that are currently geared to intercept a regular ICBM-attack over the Arctic or from the west (North Korea).

I should ad here: "for the time being".... The logical answer by the US (unless they chose to continue to ignore China with regard to BMD, as they did untill now) will now be to extend their BMD coverage to the south. For countering FOBS, they could use the same AEGIS SM-3 technology that they used to down the USA 193 satellite in 2008 (Operation Burnt Frost).

Here are two maps I made, one for a FOBS attack on Washington DC from China and one for a FOBS attack on Washington DC from North Korea. The red lines are ballistic ICBM trajectories (over the Arctic), and current BMD sites are meant to intercept these kind of trajectories. The yellow lines are FOBS trajectories over the Antarctic, showing how these attack the USA "in the back" of their missile defenses by coming from the south instead.

hypothetical FOBS attach from China. Click maps to enlarge

 

hypothetical FOBS attack from North Korea. Click map to enlarge

As the USA is currently putting much effort in Ballistic Missile Defense, developing a new FOBS capacity could be a way by which China is warning the USA that even with BMD, they are still vulnerable: i.e. that they shouldn't attempt a nuclear attack on China from a notion that their BMD systems make them invulnerable to a Chinese answer to such an attack. 

FOBS is hence a way of creating and utilizing weaknesses in the current BMD capacity of the USA, as a counter capacity.

It should be remarked here that the US BMD capacity is geared towards missiles fired by Russia or by  'Rogue Nations' like North Korea and Iran. The USA seems to have largely ignored China so far with regard to BMD. Meanwhile, China is concerned with the US BMD development, particularly deployment of BMD elements in their immediate region.

So this FOBS experiment could also be a way in which China tries to force the US to finally take the Chinese concerns about US BMD deployments and the inclusion of their region into such deployments, serious. 

 

Outer Space Treaty

China (like the US and Russia) is a signatory of the Outer Space Treaty (or, in full: the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies). 

FOBS seems to be a violation of this treaty, as Article IV of the treaty clearly states that:

 "States Parties to the Treaty undertake not to place in orbit around the earth any objects carrying nuclear weapons or any other kinds of weapons of mass destruction"

This is exactly what FOBS does: it (temporarily) places a nuclear weapon in orbit around earth, so that they can later bring it down over a target.

The Soviet Union, when testing FOBS in the late '60-ies, tried to get out from under this by claiming that, as their FOBS did not complete a full orbit around the Earth, article IV of the treaty didn't apply. The US Government, surprisingly -and for opportunistic reasons- went along with this interpretation (see this article in The Space Review). Which is, pardon me the word, of course bullshit: in the sense of orbital mechanics (that is to say; physics), FOBS clearly does place an object in orbit, and it is very clear too by the fact that after launch it needs an actual, separate deorbit burn to get it down on the target.

 

North Korea and FOBS

How about North Korea? As I mentioned, FOBS has been repeatedly mentioned as a potential route North Korea might take with its nuclear missile program. Some fear that NK could be developing a FOBS capacity in order to have a means of final-revenge-from-over-the-grave from the Kim Jong Un regime in case of a 'decapitation' attempt (an attempt to end the Kim Jong Un regime by a targetted military strike on KJU and  his family members).

One reason behind this fear is that North Korean Kwangmyŏngsŏng (KMS) satellite launches were on a trajectory over Antarctica, bringing the payload over the US only half a revolution after the launch.

Compare this launch trajectory of KMS 3-2 in December 2012 for example (which comes from this 2012 blog post), to the hypothetical FOBS trajectory in the map below it: the similarities are obvious (if perhaps superficial).

KMS satellite launch trajectory (above) and hypothetical FOBS attack from North Korea (below). Click map to enlarge

It wouldn't surprise me if FOBS will quickly replace the EMP 'threath' that over the past decade has been hyped by certain hawkish circles in the US defense world, as the horror-scenario-en-vogue.

 

Something worse than FOBS? DSBS!

So, can we think of something even more sinister than FOBS? Yes, yes we can, even though so far it is completely fictional and a bit out there (pun intended).

Let us call this very hypothetical menace DSBS. It is truely something out of your nightmares.

DSBS is a name I coined myself for a so far nameless concept: it stands for Deep Space Bombardment System. DSBS at this point is purely fictional, with no evidence that any nation is actively working on it: but the concept nevertheless popped up, as a distant worry, in a recent small international meeting of which I was part (as the meeting was under Chatham House rules, I am not allowed to name participants). So I am not entirely making this up myself (I only made up the name to go with this so far unnamed concept).

The idea of DSBS is that you park and hide a nuclear payload in Deep Space, well beyond the Earth-Moon system: for example in one of the Earth's Lagrange points. There you let it lurk, unseen (because it is too far away for detection). When Geopolitical shit hits the fan, all is lost and the moment is there, you let your DSBS payload return to earth, and impact on its target.

With the current lack of any military Xspace (Deep Space) survey capacity,  such an attack could go largely undetected untill very shortly before impact. Your best hope would be that some Near Earth Asteroid survey picks it up, but even then, warning times will be short. Moreover, with the kind of impact velocities involved (12+ km/s), no existing Ballistic Missile Defense system likely is a match for these objects.

Far-fetched? Yes. But that is also something once said about FOBS...

(Note: I hereby claim all movie rights incorporating DSBS scenario's)

(added note: I only now realized, when answering a comment to this blogpost below, that, unlike FOBS or placing something in GEO, a DSBS parked in one of the Lagrange points would NOT violate Article IV of the Outer Space Treaty, because the device would NOT be in orbit around Earth (but co-orbital with Earth).

 

UPDATE 18 Oct 2021 10:45 UT and 20:10 UT: 

NOT FOBS?

China denies that they did a FOBS test: "this was a routine test of a space vehicle to verify technology of spacecraft's reusability", says a Chinese government spokesman. They reportedly also say the test happened in July, not August. That could mean that this earlier reported test flight of a prototype space plane on July 16 was concerned (a suspicion I already voiced earlier in this blogpost and at the Seesat-L list). 

Of course, as Jeffrey Lewis rightfully remarks, spaceplane technology shares a lot with FOBS technology. In Jeffrey's words:  "China just used a rocket to put a space plane in orbit and the space plane glided back to earth. Orbital bombardment is the same concept, except you put a nuclear weapon on the glider and don’t bother with a landing gear."

At the time, this space plane test was interpreted to have been suborbital, as the space plane reportedly landed in Alxa League, 800 km Badanjilin Airport, 220 km from the launch site, Jiuquan. I today however realised that this might have been a misinterpretation: it might actually have been an orbital, not suborbital, test fligth landing at the end of the first revolution. 

Indeed, I managed to create a hypothetical 41.2 degree inclined proxy orbit for a  launch from Jiuquan that brings it over Alxa League Badajilin Airport at the end of the first revolution.

Slightly more on this in this follow-up blogpost. which also points out that a Chinese source confusingly points to yet another airport as the landing site of the July 16 space plane test (if it was a space plane at all and not some upper atmospheric aircraft vehicle).

It could be that the Chinese Government is now seizing on the July 16 test to explain away a later FOBS test.

click map to enlarge

 UPDATE 21 October 2021 10:25 UT:

New information circulated by Demetri Sevastopulo, the FT journalist that broke the story, indicates that there were *two* tests, on July 27 and August 13. The first date tallies with rumours that reached me on July 29 about an 'unusual' Chinese test apparently having taken place (that I at the time erroneously though might refer to the July 16 'space plane' test).