MH17: On the Resurs-P1 image with "BUK's near Zaroshchens’ke" (twice updated)

(Note added 31 Jan 2016: Max van der Werff brought to my attention that he is "kremlintroll" and that the pdf report on the blog was not written by him, but by someone else. That was not clear to me. I have added some comments in the text below to reflect this)

[this post was editted by the addition of a (marked) new section on 17 Feb 2016]

Since my contribution to the January 22 Dutch Parliamen hearing on flight MH17, a number of people have reached out to me with satellite-related questions about MH17.

One of them was Dutch blogger Max van der Werff, who in a tweet from 28 Jan 2016 asked me if I had anything to say about this analysis (pdf) by a blogger named "Kremlintroll" [edit: this turns out to be Max himself: but the pdf analysis on his blog was by someone else]. It concerns a report with purported Russian satellite imagery of what was claimed to be BUK installations in a field near Zaroshchens'ke, on the Ukranian side of the front. It in addition includes claims that a particular US spy satellite overflew the area at the time the missile was fired.

@Marco_Langbroek mocht u tijd hebben, dan ben ik benieuwd hoe u deze studie vanuit uw vakgebied beoordeelt [6Mb] https://t.co/Wl3SzR59Q8

— Max van der Werff (@MaxvanderWerff) 28 januari 2016

I will answer Max' question here, but note that I do so without necessarily condoning Max viewpoints on MH17. There are a lot of bloggers expressing their (often very partisan) views on the case, and I prefer not to take sides with any of them at this moment.

At the same time, when satellite observations are brought up, I would like to see to it that the information presented is correct. So I will provide some of that information below, as it pertains to this case.

My initial intent was to keep it focussed at information about satellite passes. This is factual, objective information. While checking pass data for Resurs-P1 I did however note something that appears off with regard to one of the images. I will discuss that as well, with some reluctance: but given that I mentioned my doubts on twitter, it is fair that I should present the reasons for my doubts.

The imagery comes from a Russian government website and was earlier the target of a "photo forensics" analysis by the Bellingcat collective. The latter analysis has drawn fire from professional photo-forensic analysts, who say the analysis was flawed. This critique comes from knowledgeable people on this matter, so should be taken seriously imho.

click image to enlarge

The image (reproduced above) purports to show Ukranian BUK installations in a field near Zaroshchens'ke in Ukraine, 47 deg 59' 00" N, 38 deg 27' 05" E. Text on the image states it was taken on 17 July 2014 at 11:32 (no timezone given, but presumably standard Moscow Time, UTC +3).

The pdf in the blog by "Kremlintroll" discusses the image as part of a larger narrative. In addition (and this was my initial focus), the author of the pdf claims that a US spy satellite actually overflew the MH17 disaster area at the time the missile was fired:

"According to our data from 17:06 till 17:21 Moscow time on July 17 over the South-Eastern territory of Ukraine flew a US space satellite. This is a special device of the experimental space system designed to detect and track various missiles launches"

[edit: the quote above is purportedly from a Russian officer, Lt-Gen Makushev]

US spy satellite fly-over?

Let us examine the latter claim first, as this is squarely within my field of expertise. As we will see, the claim appears to be false.

The description seems to refer to one of the Space Tracking and Surveillance System (STSS) demo satellites in Low Earth Orbit (note the given pass time of 15 minutes in the quote above, indicating a satellite in Low Earth Orbit). They are experimental satellites for tracking missiles, serving a role initially projected for the (cancelled) SBIRS LOW segment.  A pass of one of these satellites indeed takes about 15 minutes.

These particular satellites are tracked by our network. I checked their positions for 17 July 2014, 13:20 UT (the time of the MH17 disaster). They did not have sight of the Ukraine at that moment.

STSS demo 1 and STSS demo 2 (2009-052 A and 2009-052B) move as a pair at a fixed distance of each other: STSS demo 1 passes a given location 10 minutes after STSS demo 2 does, along a similar track.

STSS demo 2 passed over the MH17 crash area around 12:35 UT, and STSS demo 1 did so around 12:45 UT. This is more than half an hour before the MH17 disaster took place. STSS demo 1 lost view of the area around 12:55 UT, still 25 minutes before the disaster. At 13:20 UT, the time of the disaster, the satellites were south of Australia, well away from the Ukraine (map below).

click image to enlarge

STSS-ATRR, a third satellite connected to this program, was just east of Sakhalin at that time, so nowhere near the Ukraine either.

Another US spy satellite, USA 161, did pass over the area near 13:20 UT (see my previous post here). This is however a KH-11 optical reconnaissance satellite, not one designed to track missiles as claimed in the pdf analysis hosted by Kremlintroll. It also did not pass over the south-eastern territory of the Ukraine, but well west of the area in question. See my earlier post for a discussion of what this satellite might, or more likely given amongst others that the area of interest was very periferal in the footprint, might not have imaged.

In other words: the claim about a US missile-tracking satellite in Low Earth Orbit overflying the Ukraine at 17:06-17:21 Moscow daylight saving time (13:06-13:21 UT), is factually incorrect.

Of course, we should realise that three SBIRS satellites for missile detection in higher orbits (HEO and GEO) with (semi-) permanent view of the area did cover the relevant area, as I reported to Dutch Parliament, and in that sense this discussion is slightly academic: early warning satellites for missile launches did potentially observe the Ukraine at that time. This SBIRS high component in HEO and GEO however clearly is not the low orbit (fly-over time listed as 15 minutes) experimental missile tracking satellite system the Russian officer was referring to. So, this specific information is incorrect.


The photograph

So what about the satellite photograph distributed by the Russian government, showing purported BUK systems just south of Zaroshchens'ke and discussed in the pdf hosted by Kremlintroll as evidence for Ukrainian BUK deployment in the area.

I was, and am, reluctant to discuss this photograph.

First, I am knowledgeable about satellite orbits, satellite positions and satellite system specifics (the kind of factual information I provided to the Parliament committee during the hearing of Jan 22): but I am not a photo interpreter.

I want to emphasize this. Analysis of this kind of imagery preferably should be done by a professional photo interpreter.

Second, following my role in the Parliament hearing, I prefer to refrain as much as possible from making any statements that might be misconstrued as 'taking sides'.

Nevertheless, while looking at satellite pass information I noted something about this photograph, that I think is relevant. With some reluctance, I provide these observations here in this blogpost. I want to make clear that this only concerns this particular photograph: I am not saying anything about other evidence presented by various parties, and importantly: I have no desire to analyse more images. Again: that should better be done by professional photo interpreters. In a way, given the way this quickly developed on twitter, I regret mentioning my doubts about the satellite image in public, even though (as discussed below) I stand behind these doubts. Given that I mentioned my doubts on twitter, it is fair that I should present the reasons for my doubts below.


1. the satellite

First, the satellite that took the image. The image lists a time, 11:32 on 17 July 2014. Resurs-P1 (2013-030A), a Russian imaging satellite with 1-meter resolution, passed the area shown in the photograph at 08:32 UT (11:32 Moscow Standard Time, or 12:32 Moscow Daylight Saving Time) - an identification earlier also made on a Russian webforum. Other high-resolution Russian imaging satellites do not match the pass time listed. The assumption that the image was made by Resurs-P1 therefore appears a valid one and will be the starting point of the discussion below.

click image to enlarge

Resurs-P1 culminated at 57.5 degrees elevation at 08:32:46 UT (July 17th 2014 - that is 11:32:46 Standard Moscow Time, 12:32:46 Moscow Daylight Saving Time) as seen from the field imaged in the photograph (which is at 47 deg 59' 00" N, 38 deg 27' 05" E). The satellite subpoint was some 281 km west of the location shown on the photograph at the moment of culmination. The location on the photograph is within the satellites known image swath width of ~950 km (~475 km to each side of the satellite nadir).

It is therefore possible that Resurs-P1 did take an image of this field at the listed time.

That does however not necessarily mean that the image is genuine. Something isn't sitting well with me regarding this image, raising my suspicion. I will discuss this below.


2. the photograph: suspicions

(again, I want to emphasize that I am not a professional photo interpreter. Keep that in mind)

So far, what I have written above is all straightforward factual: where were what satellites at a specified moment? What I am going to write below has a larger factor of interpretation.

As mentioned, Resurs-P1 culminated at a maximum altitude of 57.5 degrees for the location in question (that is a factual observation).

This immediately made me uneasy about the featured satellite photograph. For this image seemed to be a head-on image, taken with an angle to the horizon of near 90 degrees (straight down), rather than under an oblique 57.5 degree angle.

The image should, with a culmination altitude of 57.5 degrees for the satellite, instead show the installations obliquely (i.e. skewed, i.e., not just show the tops but also show parts of lateral sides of the purported BUK installations). It should also show the landscape somewhat obliquely.

Resurs-P1 passed west of the area in question. This is towards the left side of the image. The image should therefore show the BUK installations somewhat skewed with something of the lateral sides visible on the left hand side.

I used sketchup to make a simple block-model with the dimensions of a BUK (roughly 9.9 x 3.3 x 3.8 meter), and then rendered it under a 57.5 degree angle with the horizontal. The image below shows the result as an inset in the original image.

To me, it appears that the photograph indeed should show more of the lateral sides of the purported BUK installations than it does: the installations shown in the image appear to be seen too-much head-on compared to the modelled view under a 57.5 degree angle.

There is also something off in the positions of the shadows. They should be slightly displaced to the left, compared to what the image appears to show (the sun was at azimuth 150.7 degrees, i.e. southeast, and elevation 60.6 degrees at 8:32:46 UT. The shadows should point slightly to the left in the image, even more so if the image is taken from a point to the west of the area under a 57.5 degree or smaller angle).

Taken together, it suggests that the photograph does not show a scene compliant with the geometric situation at 8:32 UT on 17 July 2014 as seen from Resurs-P1.

As a caveat, I should emphasize that we are talking about structure at the edge of the satellite's image resolution here, with objects only a few pixels wide (and again: I warn that I am not a professional photo interpreter). There might also have been done some unknown image processing, including resampling, as part of preparing the photo for publication. Still, I feel there is reason to be very cautious about these images.

[Edit: extra material added Feb 17, 2016, now following:] 

The previous discussion was from the viewpoint of an image taken around culmination of the satellite for the area in question, 08:32:49 UT. In a follow-up discussion about this post on Twitter, it was brought up that the image might have been made before culmination when the satellite was still north of the location. That would better match the listed time, 08:32.

I therefore did a new model simulation, based on the satellite-to-location angles for 08:32:00 UT (azimuth 335 degrees (i.e. N-NW), elevation 45.1 degrees). It is given below. Again, it does not appear to match. It should be noted here that from known specifications, 45 degrees is near the limit of what the satellite needs, in terms of elevation angle, in order to image a location.

click to enlarge

In the other imagery provided by the Russian MOD, there are discrepancies too indicating that the images were not taken at the claimed dates and times. A very clear one is the one below (source), that purports to be an image taken on 14 July 2014 11:40 Moscow time (08:40 UT). The Russian optical reconnaissance satellite Kosmos 2486 (Persona 2, 2013-028A) culminated at 08:40:54 UT at an elevation of 83 degrees for this location.

It is however interesting to compare the configuration of vehicles on a parking lot in that image . These vehicles do not seem to be used much. Using Google Earth imagery from April, May and July 2014, a clear long-lasting change in the configuration happens before July 2nd: one vehicle is lightly replaced, and a new vehicle is parked in what previously was an empty space.

click to enlarge

Comparing this to the vehicle configuration on the Russian MOD image from "14 July 2014", shows the first vehicle still in place and the empty space in reality filled in before July 2nd, still an empty space. So I am in agreement here with the observations made by Bellingcat in June 2015: the Russian MOD image claimed to be from "14 July 2014" in reality is from before July 2nd, 2014.

"But how about the Ukrainians?", some have asked me. Well: the vehicle pattern does positively fit with the "July 12" image (upper right image above) published by the Ukrainians (and later ostensibly 'rebutted' by the Russian MOD here: but we now note it are in fact the Russian MOD images that are doctored).

This latter image appears to be commercial imagery obtained from Digitalglobe, shot by the Worldview 1 satellite (which isn't anything unusual: several governments use the services of Digitalglobe). It made a pass culminating at 55 degrees at 08:11 UT (11:11 local time) on July 12.

Note that the Russian MOD claim here that:

"At the time specified in the images, the American electro-optical reconnaissance satellite of the Key Hole series was flying over the crash site area, so the source of the images for Ukrainian Security Service is obvious"

This Russian MOD statement about the Ukrainian images is factually incorrect (as was their claim for STSS passes around the time of the MH17 shootdown, as we have earlier seen): the dates and times listed for the Ukrainian images do not match with passes of  US KH-11 optical satellites.

But they do all match passes of three Digitalglobe satellites: Worldview 1, Worldview 2 and Geoeye 1. Evidently these satellites made these images, not US military KH-11 satellites.

So the Russians are making a lot of factually incorrect claims in this case.

[end of section added 17 Feb 2016]


A few last words on my position in this

I want to note that this is the first and last time I will, with regard to MH17, foray into the domain of satellite photo interpretation, also given the very strong reactions this has already spawned on media like twitter. Agitprops from all sides have jumped on it.

I prefer to keep my further involvement with MH17 focussed on providing factual data on satellite positions and satellite system specifications, in line with the role I played in this month's Parliament hearing. That is a position only people with an agenda could take issue with.

With all the things that have come up over the past 1.5 year, and with multiple parties involved clearly unwilling to provide pertinent data, I have taken a step back, opinion-wise. In the current situation, my aim is to not point fingers until verifiable evidence is put on the table. The report of the Dutch Safety Board is a first step into that direction, but there are still many aspects of the case that are very unclear. Clarifying these was the main point of the Parliament hearing of January 22.


NOTE ADDED 4 March 2016,  10:30 UT:

- sigh.....deep sigh.... -

I wish it would not be necessary to get into this, but some spin deserves a rebuttal when the spin in question really is too outrageous:

As an example of how some propagandists are trying to spin unwelcome analytical results (such as those of this analysis), I bring you the twitter troll Deus Abscondis.

For reasons only known to him/herself, (s)he tries to (falsely) insist that I initially ignored the Persona 2 satellite. The goal, of course, is to try to suggest that my analysis should be dismissed and my expertise questioned.

Here is the flaw in his/her logic: the fact that I did not mention Persona 2 until Deus Abscondis named that satellite on twitter (and I answered that Persona 2 appeared to have made some of the other images) simply does not mean I didn't consider Persona 2 earlier. I did, matter of fact.

It is important to realize that my blogpost initially (and at the moment Deus Abscondis posted his twitter question) discussed only one image: that with the "BUK's in a field near Zaroshchens’ke".

I wrote about this image, in the original blog-post (emphasis added):

The image lists a time, 11:32 on 17 July 2014. Resurs P1 (2013-030A), a Russian imaging satellite with 1-meter resolution, passed the area shown in the photograph at 08:32 UT (11:32 Moscow Standard Time, or 12:32 Moscow Daylight Saving Time) - an identification earlier also made on a Russian webforum. Other high-resolution Russian imaging satellites do not match the pass time listed.

Take a look at that last sentence.

The sentence highlighted in black makes very clear that I considered other satellites than Resurs P1 as well. The latter category of checked satellites not fitting the pass time for the Zharoshchens'ke image actually included Persona 2.


In addition to Persona 2, the ones I checked but rejected also included Resurs DK1, Kanopus V1 and the Kobalt-M photoreturn mission Kosmos 2495 (still on-orbit at that time).

When Deus Abscondis days later asked about whether I had considered Persona 2,  my answer to him was that Persona 2 could have made some of the other image, i.e. I told him/her that I was well aware that some of the other imagery could be from Persona 2. I also informed him that this other imagery was not unproblematic either (and updated my blogpost next to show why):

Note that nowhere does my answer implicate that I had not considered Persona 2 in my original analysis, of the Zharoshchens'ke image. I simply point out that Persona 2 is of relevance only to some of the other imagery, not to the image discussed at the blog at that moment. Discussion of that other imagery was added later, as an update of the post.

The twist that Deus Abscondis is now trying to give to that conversation, is therefore extremely insincere.

It is a good example of the kind of spin some propagandists are producing when trying to suppress unwelcome analytical facts.


Note added 10 June 2020:

In the MH17 trial yesterday (June 9 2020), the prosecution tore apart the validity of this imagery as well, based on an analysis by ESA.

SIGINT, IMINT and MH17

(this post continues discussions in earlier posts on possible classified space-based observations of the shootdown of Malaysian Airlines flight MH17 over the Ukraine in 2014)

My position paper written for the Dutch Parliament Foreign Affairs committee hearing of Jan 22 (see my previous post) has a strong focus on infra-red detections of a missile by SBIRS. There are however a few other relevant aspects of Space Based observations in connection to the MH17 disaster that I could not cover in the space available to me for that paper.

In this post, I will provide some brief additional information about:

1) potential roles for IMINT satellites;
2) the positions of SIGINT satellites.


Optical and radar IMINT

1. optical IMINT

Both (unclassified) commercial and (classified) military satellite systems for high-resolution optical imagery (Image Intelligence, IMINT) exist, and both sources will be discussed below.

Optical and radar imagery obtained in the hours before, as well as during the event, might be used to look for missile systems, both on the Ukrainian as well as separatist sides of the front, in a wide circle around the site of the shootdown. It could also be used to verify the reconstruction of the purported movements of a Russian BUK system published by citizen journalist team Bellingcat, a study which is not uncontested. The Bellingcat team places the BUK in certain places at certain times, and if space-based imagery (either military or commercial) for those locations and times exist they could perhaps verify these claims.

The US military has one classified system of optical satellites with a (much-) better-than-1-meter capability: the KH-11 IMPROVED CRYSTAL/Evolved Enhanced CRYSTAL (aka 'Keyhole' or 'KENNAN') which reportedly (and theoretically, from known 2.4 meter mirror size specs) have a resolution in the order of  10-20 cm.

Mid-2014 this system consisted of four satellites: USA 161, USA 186, USA 224 and USA 245. All of these have been discussed on this blog before and are tracked by our amateur network.

We have accurate tracking data on three of these, USA 161, USA 224 and USA 245 for the days around 17 July 2014 and hence can pinpoint when these potentially had the crash area in their sight to better than a minute. For USA 186, which was actively manoeuvering around that time and for which we have a gap in our coverage form June to August 2014, pass times are a bit less certain and constrained to about 20-30 minutes accuracy.

First, we can positively affirm that one of the KH-11, USA 161 (2001-044A) actually had the Ukraine in its potential view during the incident at 13:20 UT:

click images to enlarge

Please note well: this does however NOT mean that USA 161 delivered imagery of the event. A number of factors should be taken into account:

1. the cloud cover at that moment, which might hinder imagery;
2. the crash site is located quite in the perifery of the satellites footprint area;
3. these satellites do likely not make images continuously, but only if commanded to do so, for specific areas of interest;
4. there is the question of whether USA 161 was still operational at that time. It was the oldest of the on-orbit KH-11, being launched 14 years earlier. Only a few months later it was de-orbitted, so it was clearly at the end of its lifetime.

In addition to their KH-11 system, the US military hires space on commercial high resolution optical IMINT satellites from the US commercial firm Digitalglobe (the same firm that supplies Google Earth with satellite imagery).  

Digitalglobe operates a number of satellites with a better-than-1-meter capability: Geoeye-1 (0.4 meter resolution), and Worldview 1, 2 and 3 (0.25-0.50 meter resolution). Most of the satellite imagery that the US Department of Defense supplies to the press (when briefing on the military situation in e.g. North Korea, Syria and Libya) comes from these commercial satellites.

Imagery from these same Digitalglobe satellites is also available commercially, to any interested party with money. And in addition to DigitalGlobe, the European company Airbus Defense and Space also offers commercial high-resolution optical imagery from its SPOT and Pléiades satellites. Pléiades 1A and 1B offer a 0.5 meter resolution. SPOT 5 and 6 offer a 2.5-1.5 meter resolution.

Accurate orbital data from non-classified sources are available for all the commercial imagers for 17 July 2014. The satellites in question made several daylight passes over the area in the morning of July 17, 2014, between 8:00 and 10:00 GMT, i.e. during the 3 to 5 hours before the shootdown, a period when the skies were still less clouded.

This does not mean that they necessarily made imagery of course. Yet any imagery these commercial Digitalglobe and Airbus satellites did make on July 16, 17 and 18 have the advantage that they are not "classified", unlike the US military data, meaning that they could be used and published without diplomatic problems by the Dutch government in the Dutch criminal investigation into the disaster.

I would therefore expect the Dutch OM to either buy or subpoena all potential Digitalglobe and Airbus imagery from these dates. They can be used to reconstruct missile system positions in the area (both on the Ukrainian, the separatist and Russian sides) within range of the shootdown location, and they can be used to hunt for missile transports (see my earlier remarks about the Bellingcat claims). The Dutch Air Force has an imagery analysis unit that is well suited to help with such an analysis. Including imagery from the days before and after the incident as well is useful to look for differences between imagery of these respective dates.


2. Radar IMINT

The US military has two systems for high resolution radar IMINT: the Lacrosse (ONYX) system of which currently only one satellite, Lacrosse 5 (2005-016A) is left on-orbit, and the radar component of the Future Imagery Architecture (known as TOPAZ), consisting of three satellites: FIA Radar 1, 2 and 3 (2010-046A, 2012-014A and 2013-072A). These systems should be capable of providing imagery with sub-meter resolutions, and like optical imagery, they can be used to look for the presence of missile systems in the area. They have the added bonus that they are not hampered by cloud cover, unlike optical imagery.

Apart from the USA, the German military also operates a radar satellite system, the SAR-Lupe satellites. The French military likewise operates its own radar satellite system, the Hélios system. Japan operates the IGS system (which includes both optical and radar satellite versions).

All of these satellites made passes over the Ukraine at one time or another on July 17 2014, so all of them might have provided useful imagery.  FIA Radar 3 made a pass right over the area in question near 11:43 UT for example, some 1.5 hours before the tragedy. FIA Radar 2 made a pass over the area at 18:00 UT, 4.5 hours after the shootdown. These are just a few examples.

Given what was happening in the area around this time, and the strong concern of NATO and the EU about this, it is almost certain that imagery of the area was collected by these US, German and French satellite systems.


SIGINT

My position paper briefly mentions that a number of countries have space-based SIGINT (Signals Intelligence) capacities. This does not only concern capacities for (for example) the NSA to tap into your cellphone and satellite telephone conversations: another important strategic aspect of space-based SIGINT is the capacity to detect radar and telemetry signals from enemy weapons systems. Such detections allow identification of the used weapons system (each system has its own 'signature'). They also allow, according to remarks by the then NRO director Bruce Carlson in a speech from September 2010 at the National Space Symposium, geolocation of the source of this radar signal (in the case of MH17: geolocation of the Target Acquisition Radar of the launch unit).

The US military has a number of SIGINT systems in several types of orbits: Low Earth Orbit (LEO) below 1500 km which allows coverage of a few minutes during a pass over a target; and Highly Elliptical Orbit (HEO) and geosynchronous orbit (GEO), which allow to monitor targets for many hours (HEO) to continuously (GEO) from distances of 36 000+ km.

France has a number of SIGINT satellites in LEO. China no doubt has SIGINT satellites too, as does Russia. For the moment I will focus on the US systems. I must ad that I did check the French systems as well but none of the French systems (ESSAIM and Elisa, both in LEO) had sight of the Ukraine at that time.

The US systems, under the catch-all codename ORION, include the TRUMPET-FO which move in HEO. One of them is USA 184, mentioned before in the discussion of SBIRS as it has a piggyback SBIRS capacity in addition to its main SIGINT role.

There are also the big MENTOR satellites in GEO, plus two MERCURY satellites also in GEO, and the older VORTEX system. Of these systems, TRUMPET-FO, MENTOR and MERCURY are certainly still active based on their orbital behaviour.

The map below shows the positions of those satellites in this series for which we have enough tracking data to allow a reconstruction of their positions and footprints on 17 July 2014, 13:20 UT and which had the MH17 crash area within potential view:

click map to enlarge

Again: this does NOT necessarily mean that all of these satellites were actively monitoring the Ukraine at that time. Quite a number of them will have been tasked on the Middle East.

Yet, given the strong NATO interest in events in the Ukraine at that time, notably the rising concern about advanced surface-to-air missile systems following the shootdown of a Ukrainian Antonov-26 a few days earlier, I would be surprised if none of them monitored the Ukraine at all.


A clarification note on the position of USA 184 (SIGINT/SBIRS)

In my position paper written for the Dutch Parliament Foreign Affairs committee meeting coming Friday, I included this map with the positions of three SBIRS satellites with view on the Ukraine at that time:

click map to enlarge

I should point out here that there is some leeway in the exact position of USA 184, depending on whether it made a corrective manoeuvre to maintain its Mean Motion of about 2.00615 revolutions/day or not since the day we last observed it.

If it did, its position would be slightly more westward compared to the position depicted above, i.e. in a position just north of Scotland rather than above the Norwegian coast:

Let me be clear: this does NOT influence the conclusions of my position paper: the MH17 crash site in both variants is well within the field of view as seen from USA 184, i.e. the satellite could potentially provide both Infra-red and SIGINT detections. In the interest of accuracy, I thought I should however mention it here.


Acknowledgement -  I thank Mike McCants (USA) and Ted Molczan (Canada) for discussions about satellite positions, notably concerning USA 184.

Tracking USA 161

click image to enlarge

I am a bit behind with posting the image above taken a week ago, on 3 June 2014 . It shows the KH-11 Keyhole/CRYSTAL optical reconnaissance satellite USA 161 (2001-044A), which was recently recovered.

With new observations including mine, the orbit is now getting better defined. During the winter blackout, the orbit of the satellite appears to have been further circularized to a 389 x 391 km orbit, by a small perigee rise.

In the image above, another object is also visible: a Falcon 9 r/b, 2010-066K, at over 5000 km altitude at that time.

Sorting out the confusion: USA 161 and IGS 8R

Okay, so yesterday considerable confusion arose about the current orbit of USA 161 (see previous post). This was due to the (luckily shortlived) confusion between two objects: the real USA 161, and a Japanese spysat that was briefly mistaken by me for USA 161.

The object which I photographed during the night of May 30-31 and which Björn Gimmle photographed from Sweden on April 22, turned out to be not USA 161 but, as Cees Bassa pointed out, another classified object we had "lost" in the winter blackout: IGS 8R (2013-002C), a Japanese radar imaging satellite launched early 2013.

So the image below actually shows IGS 8R flaring brightly, not USA 161 as I initially thought:

click image to enlarge

Luckily, Russell Eberst in Scotland observed the real USA 161 on June 1. Together with the observation by Leo on May 23, this means we do have an idea of the current orbit of USA 161 now, although further refinement through more observations is necessary. What is clear, is that USA 161 still is in the same orbital plane it was in when we lost it in August 2013. It's RAAN difference with the primary East plane KH-11 USA 224 is still 20 degrees, and it's orbit is sun-synchronous and about 385 x 393 km (these are approximate values which are subject to change, as the current orbit is preliminary and needs some refinement with more observations). The current KH11 Keyhole/CRYSTAL constellation now looks like this:

The short-lived confusion of yesterday could arise because both objects (IGS 8R and USA 161) currently move in a similar orbital plane. This can be seen in the image below, where the IGS 8R orbit is yellow and the USA 161 orbit is light grey:

This is the kind of confusion that can arise when multiple objects who's orbit have not been recently updated, move in a similar orbital plane. It does not only happen to us amateur trackers: even the professionals at JSpOC sometimes confuse objects.

Actually, this situation ended positive with a double recovery: that of USA 161, and that of IGS 8R.

[AGAIN UPDATED] USA 161 recovered (?) - and new ideas on changes in the KH system

CORRECTION 1 June 2014: The object I observed on May 31 turns out to be NOT the KH USA 161, but one of the IGS objects, IGS 8R (2013-002C) which we had 'lost' in the winter blackout, just like USA 161. Their orbital planes happen to be very close (with a few tenths of a degree in inclination and a few degrees in RAAN) at the moment.

This renders the whole story below incorrect and hence moot.

Luckily, Russell Eberst did observe the real USA 161 last night (June 1) and his observations fit with Leo's observations from May 23. More in a new post later. (this new post is up now here)

ML, 01/06/2014

- STOP PRESS - (31 May 2014, 19:00 UT). Okay. Cees Bassa thinks last night's object is not USA 161. See here. So read the story below with caution: the jury is still out on all this.

Although it all was/is a bit confusing, it appears USA 166 (2001-044A), the secondary East plane KH-11 Keyhole/CRYSTAL has finally been recovered. [UPDATE: OR PERHAPS NOT???]. It had not been positively observed since August 2013 and over the past half year had been hiding in the northern hemisphere winter blackout.

USA 161 ?. IGS 8R last night

(click image to enlarge)

Initially, Leo Barhorst in Almere (NL) appeared to have recovered it on May 23. However, his observed object now turns out to not have been USA 161 but an unidentified other object.

Last night it was clear, after a very rainy week. Suffering from a bout of insomnia, I took advantage of the clear skies by conducting a 30 minute plane search, from 01:00 UT to 01:31 UT (May 31), using the EF 2.0/35 mm wide angle lens.

Just as I was about to abandon the effort at 01:30 UT, a bright and fast satellite appeared with a direction that was correct for USA 161 in a generally correct area of the sky. I managed to capture it on two images, the second one of which is depicted above. The object was about mag +2 when I first visually picked it up, and then becoming brighter as it produced a slow flare to mag -2 near 01:30:27 UTC. The image above shows the slow flare moment. It moved fast, producing long trails on the 10 second images with the 35 mm wide angle, so it evidently was near perigee.

The object could not be matched to any known object, but did appear to move in the general secondary East orbital plane of the KH-11. Visually, the slow bright flare it showed was quite typical for the KH-11 too. So I was (and am) fairly certain it is USA 161. Or not? Problem was, my observation was difficult to match with Leo's observation a week earlier...

After I reported my observations, Ted Molczan next managed to positively match my object to a UNID observation by Björn Gimmle in Sweden on April 22 (so over a month earlier), proceeding to fit a very reasonable orbit. The suggestion of this all is, that Leo's object from May 23 was something else, as it does not fit well with the other observations.

The preliminary orbit calculated by Ted, which needs to be refined by further observations, suggests that USA 161 made a manoeuvre into a (compared to the orbit it was last seen in in 2013) slightly higher orbit of 411 x 425 km, with the orbital inclination changed by half a degree to 97.52 degrees. This is the same orbital inclination as USA 129 (1996-072A), the former secondary West plane KH which we have recently "lost" and which is suspected to have been de-orbitted, was orbiting in.

Like the drifting secondary West plane KH USA 186 (2005-042A, see several previous posts on this blog for a discussion), USA 161 is no longer sun-synchronous as a result of this manoeuvre, and hence in what appears to be a plane transfer orbit. Its distance in RAAN relative to the primary East plane KH-11, USA 224 (2011-002A), has increased and will keep increasing steadily until it makes a corrective manoeuvre (which I suspect will happen near June 12, see below).

The orbital constellation for May 31 looks like this:

(image removed)

click image to enlarge

The current situation is that the two new primary plane objects, USA 224 and USA 245, are keeping a more or less steady plane distance (in terms of RAAN) of 48.5 degrees. The two (older) secondary plane satellites, USA 186 and USA 161 however have now both lost sun-synchronicity, and are both drifting outwards with respect to the orbital planes of their corresponding primary plane satellite.

Frequent readers of this blog will remember that I initially expected USA 186 to manoeuvre back into a non-drifting sun-synchronous orbit when the RAAN difference with USA 245 was 10 degrees, early February. That didn't happen. As a secondary option, I then thought it would manoeuvre when the difference was 20 degrees, early May. That didn't happen either. I then was at a loss as to what "they" were planning to do with USA 186.

Now USA 161 has been recovered and turns out to have been manoeuvered into a drifting plane-changing orbit as well, just like USA 186, I am getting a possible idea again about what they might intend. Please note: I have been wrong twice before, so my track-record in these kind of predictions is not quite good :-p

Nevertheless: assuming that symmetry is what is being aimed for, I think both objects (USA 186 and USA 161) will manoeuvre back into a non-drifting, sun-synchronous orbit on or near June 10 to June 12.

On May 31 the RAAN difference between USA 245 (primary West) and USA 186 (drifting secondary West) was 23.0 degrees. The RAAN difference between USA 224 (primary East) and USA 161 (drifting secondary East) was 23.7 degrees. Their rate of drift is different: it is -0.11 degrees/day for USA 186 and +0.056 degrees/day for USA 161 (i.e., USA 186 is drifting twice as fast as USA 161). These differential drift rates mean that at some point in time, both satellites will reach a matching value in RAAN difference with their primary partner, i.e.be at similar RAAN distances from their primary partner on the same day. This is depicted in the diagram below:

(image removed)
click diagram to enlarge

What can be seen from the diagram, is that this moment will occur in about 10-12 days from now, near June 10-12. On June 12, both satellites (USA 186 and USA 161) will reach a matching difference in RAAN of 23.3 degrees with their primary partners USA 245 and USA 224. Interestingly, this value is very close to 0.5 times the RAAN difference between the primary plane satellites, USA 224 and USA 245 which are 48.5 degrees apart in RAAN.

But please be advised: until now, I was wrong each time I thought I could make sense of it....

USA 224 recovered, USA 186 still drifting, and looking for GPS IIF-6 20 minutes after launch

For various reasons, I am a bit late in keeping the reader up to what is happening to the KH-11 Keyhole/CRYSTAL system of optical reconnaissance satellites.

USA 186 (2005-042A), the secondary West plane KH-11, is still in a non sun-synchronous orbit and hence still drifting westwards. It is drifting for over half a year now. The difference in RAAN with USA 245, the primary West plane KH-11, is now over 20 degrees (21.8 degrees on May 19th). I am very curious as to when the drifting will stop, if ever. If it continues to drift for many weeks to come, we should contemplate whether perhaps the satellite is "dead", i.e. has lost manoeuverability. Problem is that NW European observers temporarily have lost visibility of the satellite, due to the current short nights. Tracking all comes down now to observers in the US and southern Europe.

Meanwhile, Russell Eberst in Scotland recovered USA 224 (2011-002A), the primary East plane KH-11, on May 9th. It is in a 260 x 1006 km orbit, which means it has slightly lowered its apogee. Before the winter blackout it was in a 258 x 1023 km orbit. The difference in RAAN with USA 245, the primary West plane KH-11, is now 48.5 degrees.

My own first observation of USA 224 was in the night of May 16-17. The image below shows it crossing through Corona borealis:

click image to enlarge

USA 161 (2001-044A), the secondary East plane KH-11, has still not emerged out of the winter blackout. Meanwhile, USA 129 (1996-072A) has gone missing since April 24 (see a previous post). There is a good chance it has been de-orbitted.

The current KH-11 constellation now looks like this (where the current orbital configuration of USA 161, in red, is uncertain, and USA 129 left out as it is no longer in its old orbit, and presumed de-orbitted):

click images to enlarge

In the early morning of May 17 (evening of May 16 in the US) and after a one day delay due to bad weather, a new GPS satellite, GPS II-F6 was launched from Cape Canaveral on a Delta IV rocket. It would pass over the Netherlands some 20 minutes after launch, still ascending and still attached to the 2nd stage. A number of search orbit had been published, but it looks like none of these was very accurate. I visually observed a bright UNID near 00:24:00 UT (May 17) moving just a few degrees to the 'right' of Altair on a trajectory parallel to the predicted ones but some 20 degrees cross-track in a southern direction. It was already descending over the roof when I picked it up, so I had no time to snap a picture alas. It did not match any known object so I am quite confident it was GPS II F-6 on its way to orbit. It was bright, about mag +1 to 0.

An update on the evolving KH-11 Keyhole/KENNAN/CRYSTAL system

In several previous posts from September 2013 onwards, I analysed and prognosed changes to the KH-11 Keyhole/KENNAN/CRYSTAL optical reconnaissance satellite system. Main focus was on the changes, notably in the orbit of USA 186 (2005-042A), following the addition of USA 245 (2013-043A) as a replacement for USA 186 in the Keyhole primary West plane.

Indeed, as predicted, USA 186 was moved out of the primary West plane, and started to drift towards the secondary West plane in mid-November 2013 following a manoeuvre that changed its inclination and made it loose sun-synchronisity.

USA 186 is still drifting westwards. It currently is moving westward at a rate of 0.11 degree/day relative to USA 245 (2013-043A), the primary satellite in the West plane since the autumn of 2013. The difference in RAAN between the two satellites currently is slightly over 16 degrees:

 click images to enlarge

Late 2013 and early 2014, I expected that the drift would end early February 2014, when the RAAN difference between USA 245 and USA 186 reached 10 degrees, the old separation between USA 186 and USA 129, the former primary and secondary West plane satellites. I was proven wrong with my prediction, when USA 186 continued to drift past that date.

I then turned to a second scenario: that the intended RAAN difference between USA 245 and USA 186 will be 20 degrees, similar to the difference between USA 224 and USA 161 in the East plane.

With the current rate of precession of 0.1111 degrees/day relative to USA 245, the RAAN difference between USA 186 and USA 245 will reach 20 degrees near May 1. So I expect USA 186 to manoeuvre into a lower, sun-synchronous orbit on or near that date. The KH-11 constellation will then look like this:

click images to enlarge

An open question is what will happen to USA 129 (1996-072A), the over 17 year old former secondary West plane satellite. I still think it will be de-orbited somewhere this year. But I have been wrong before.

Note: the orbits for USA 129, USA 186 and USA 245 in the West plane in the images above are based on recent observations. The East plane satellites USA 161 and USA 224 have not been observed since autumn 2013, and will not be visible from the Northern hemisphere before mid-April. There is therefore a possibility that one or both have moved, but since we have no information on their current whereabouts, I have depicted them in their 'old' orbital planes of the autumn of 2013 relative to the West plane.

USA 245 now also recovered

One by one the KH-11 KENNAN/CRYSTAL ("Keyhole')  optical reconnaissance satellites are emerging from their winter blackout on the Northern hemisphere (see a previous post). After USA 186 (2005-042A) in the secondary West plane late February, now USA 245 (2013-043A), the new primary West plane satellite, has been recovered.

USA 186 in the secondary West plane imaged on March 11

(click image to enlarge)

During wintertime the KH-11's are not visible from the Northern hemisphere: they are eternally eclipsed by the earth shadow during these months. Only late February/Early March they reappear. Observations during the Northern hemisphere winter season solely rest on the shoulders of our single Southern hemisphere observer, Greg in South Africa. He starts to lose sight of the West plane KH's late January to early February.

I did a failed attempt to recover USA 245 on March 3, continuously imaging its last known orbital plane for 19 minutes (10 minutes before and 10 minutes after the nominal pass time). Nothing was seen. I should have kept on the attempt longer: Russell Eberst in Scotland was more lucky that evening and got a single position. It turned out it was even more late (36 minutes) than the time period covered by my attempt.

The next person to observe it was Cees Bassa in the Netherlands on March 8. The next day, March 9, it was finally my turn and I could do my first post-winter-blackout observations! Several other observers (e.g. Jon Mikkel in Spain, Leo Barhorst in the Netherlands) also picked it up around this date.

I was nearly fooled on March 9 by a bright object that appeared about two minutes before USA 245, moving along a similar track. It turned out to be the French optical reconnaissance satellite SPOT 4 and not USA 245 being too early. Luckily, I kept photographing and soon captured the real USA 245.

The visibility of USA 245 has since been rapidly increasing. The satellite is currently already making zenith passes for my location. The image below I shot on March 11:

USA 245 in the primary West plane imaged on March 11

(click image to enlarge)

The hunt is now on for the third of the West plane objects, USA 129 (1996-072A) which should be slowly emerging from invisibility, at first only very low in the North, but soon higher in the sky during the last week of March. It was manoeuvered into a much lower orbit near January 27 (see a previous post). It will be interesting to follow it, as I still suspect it to be de-orbitted, perhaps later this year.

The East plane midnight KH-11's USA 161 (2001-044A) and USA 224 (2011-002A) will start to emerge from darkness about mid-April and have currently not been seen for several months.

USA 186 is defying the schedule

Over the past months I have posted a number of analysis and prognosis with regard to the likely changes to the KH-11 Keyhole/CRYSTAL constellation of optical reconnaisance satellites, following the launch of USA 245 (NROL-65, 2013-043A) into the KH primary West plane on August 28, 2013. The most important of these posts can be found here (Sep 16, 2013), here (Oct 12, 2013) here (Dec 22, 2013), and here (Feb 1, 2014).

One of my predictions was that USA 186 (2005-042A) would be moved from the primary West plane to the secondary West plane, 10 degrees west in RAAN from the primary plane.

Indeed, it initially seemed to keep to my prediction as mid-November 2013 USA 186 made a manoeuvre that involved a 1-degree inclination change. As a result it lost its sun-synchronous precession rate and started to drift westward relative to the other KH-11 satellites, moving orbital plane out of the primary West plane towards the secondary West plane. Its precession rate was such that it would reach a 10-degree difference in RAAN with the new primary plane satellite, USA 245 (2013-043A) near Feb 6. I therefore expected USA 186 to manoeuvre near that date, a manoeuvre that should entail an orbit circularization including a significant lowering of the apogee (after which the orbit would be sun-synchronous again and the westward drift would stop). So as Feb 6th neared, we held our breath.

And nothing happened. USA 186 did not manoeuvre.

It is still drifting westwards, at a rate of  0.12 degrees/day relative to the other KH-11 satellites. My prediction failed.

click images to enlarge

Greg Roberts in South Africa did a good job in tracking USA 186 right up to February 12. As his southern hemisphere summer observing window was coming to an end, he could no longer follow it after that date. Luckily, it is coming in reach of northern hemisphere observers, and Cees Bassa in the Netherlands picked it up on February 21 with the first Northern hemisphere observations of 2014.

Now USA 186 has not manoeuvered, it is time to entertain my alternative scenario which I presented near the end of this post on Dec 22 and this post on Feb 1.

That alternative scenario is that the drift will continue until the difference in RAAN between USA 186 and USA 245 amounts to 20 degrees (instead of 10 degrees). This is a RAAN difference similar to that between the primary and secondary East plane satellites, USA 224 and USA 161. It would create a 90-degree angle in RAAN between the outermost, secondary East and West plane satellites (USA 161 and USA 186).

At the current drift rate, these values will be reached early May.

It is clear that the current, drifting orbit of USA 186 is not an intended end state. The orbit is not sun-synchronous, a must for an optical reconnaissance satellite. The inclination change it made mid-November 2013 is such that a manoeuvre into a ~380 x 400 km orbit similar to USA 161 in the secondary East plane will restore a sun-synchronous precession rate. So that appears to be the intended goal in the future. The current non sun-synchronous orbit is meant to let the RAAN drift up to a desired value. The question now is, what final RAAN value relative to the primary plane is intended.

My guess, now it has turned out to be not 10 degrees, is 20 degrees.

Meanwhile, another question is what they intend to do with the "old" secondary West plane satellite, USA 129 (see the post here).

[UPDATED] USA 129 de-orbitted [NO!]? And USA 186 about to manoeuvre?

UPDATE 04 Feb 2014: USA 129 was NOT de-orbitted! Greg recovered it on Feb 3. It appears to have manoeuvered into an orbit with a much lower perigee. More here.

USA 129, the oldest orbiting member of the KH-11/CRYSTAL optical reconnaissance satellites, appears to have been de-orbitted during the past week.

(click image to enlarge)

USA 129 on 28 September 2013
RIP ?

On January 27, Greg Roberts in South Africa observed USA 129 (1996-072A) and USA 186 (2005-042A), two of the west plane KH-11 satellites. When he observed again on January 30, USA 129 was gone. He could not spot it on two good passes that evening.

This non-observation raises the serious possibility that USA 129 has been de-orbited somewhere between Jan 28 and Jan 30, 2014. [Update 4 Feb 2014: it was not!]

A de-orbit fits into expectations. In September and October, I published a number of analytical posts on the past and future of the KH-11 KeyHole/CRYSTAL constellation. They detail how I think/thought the constellation of KH-11 satellites will be re-arranged following the lauch of a new satellite, USA 245 (2013-043A, NROL-65), into the primary West plane of the constellation on August 28, 2013. The two most pertinent of these posts are the ones here and here.

So far, my predictions seem to have been quite in line with what consequently actually happened. I suggest that this week will see the closing overture of this spatial spy satellite ballet.

I earlier predicted that after a few months of checkout of the newly launched USA 245, the older USA 186 would be moved from the primary West plane to the secondary West plane, by shifting the RAAN of its orbit 10 degrees more westward. In doing so it would take up the position formerly filled by USA 129 during its extended mission. I also predicted that USA 186 will at some point drastically lower apogee, slightly raise it perigee, and circularize it's orbit. I in addition expected USA 129, which was over 17 years old, to be de-orbitted near the moment those goals were attained.

The latter (the de-orbit of USA 129) seems to have happened in the past few days.

So far USA 186 has also been keeping to the plan. In mid-November 2013 (on or near 12 November), USA 186 made a manoeuvre that changed its inclination by 1 degree (see my post here), causing the satellite to temporarily lose sun-synchronisity and causing it to gradually drift in RAAN from the primary West plane towards the secondary West plane. It is nearly there now. At the current drift-rate (delta 0.12 deg/day relative to the sun-synchronous drift value of the other KH-11 satellites), it will reach the former orbital plane of USA 129 and a 10-degree separation in RAAN from USA 245 (now the sole satellite in the primary West plane) within a week from now, on February 6, 2014.

click image to enlarge

The image above shows how as a result of the Nov 12 manoeuvre, the orbital plane of USA 186 gradually drifted (and as of this writing on Feb 1 still drifts) from the primary West plane to the secondary West plane between November 12, 2013 and February 6, 2014. This is exactly what I predicted to happen back in September and October.

(in the images above, the grey line is the orbit of USA 245, the white that of USA 186, and the red that of USA 129)

The next step is that I expect a large manoeuvre by USA 186 on Thursday February 6th, in which it lowers it's apogee (currently at 975 km) to ~390-400 km, and slightly raises its perigee (currently at 260 km) to ~380-390 km, attaining a much more circular and on average lower orbit with eccentricity close to 0.00055 (currently 0.05) and Mean Motion near 15.59 revolutions/day.

The current orbital inclination of  96.91 degrees is already very close to the 96.99 degree value with which such a 390 x 400 km orbit is sun-synchronous. Lowering apogee and perigee to these values hence would restore a sun-synchronous orbit and stop the drift in RAAN relative to the other satellites in the constellation. As such, the 1 degree inclination change in the satellite's orbit introduced mid-November might be a strong clue that indeed a 390 x 400 km orbit (similar to USA 161, in the secondary East plane) is intended.

click image to enlarge

The image above shows the KH-11/CRYSTAL constellation as of 28 January 2014, and excluding USA 129 which was de-orbitted on or very shortly after that date. The small yellow arrow perpendicular to the orbital plane of USA 186 indicates that I expect it to shift by an extra 0.6 degrees over the coming week.

The image below shows how the constellation will look like after the apogee-perigee changing manoeuvre which I expect USA 186 to make on Feb 6. Note the lower, more circular orbit of the latter compared to the image above:

click image to enlarge

click image to enlarge

As a caveat, there is a very small, alternative possibility that USA 186 will not manoeuvre on Feb 6th. In that case, it will keep drifting another 2.5 months untill the RAAN (orbital plane) difference with USA 245 reaches 20 degrees (and the RAAN separation of the outermost, secondary E and W planes 90 degrees). My hunch is however that this will not happen, and USA 186 will manoeuvre on Feb 6th into a sun-synchronous orbit with RAAN 10 degrees from the RAAN of USA 245, as explained above.

Note: many thanks to Greg Roberts, South Africa, for keeping an eye on the KH-11 satellites during the Northern hemisphere winter blackout!

USA 186 (Keyhole KH-11/Advanced CRYSTAL) is moving orbit, as expected

In a series of previous posts culminating in the October 12 summarizing post here, I scetched a scenario of what I think will happen to the Keyhole/KH-11/Advanced CRYSTAL constellation of high-resolution Optical reconnaissance satellites following the launch of USA 245 on August 28.

The first part of that scenario now seems to be happening: USA 186 has moved orbit.

This happened slightly earlier than I anticipated, but it does seem to be the first change in a series of changes right along the lines I expected.

The KH-11's are currently almost inobservable from the northern hemisphere (and hence my location) due to the "winter blackout". In the southern hemisphere, where it is summer, South African observer Greg Roberts has however been tracking them.

On December 10, Greg failed to recover USA 186 (2005-042A) in its old orbit. Earlier I predicted that this would happen at some point, as the satellite would likely be moved several degrees in RAAN from the primary West plane to the secondary West plane, which are 10 degrees apart in RAAN. See my earlier post here for a discussion of primary and  secondary orbital planes.

This made Greg next search for USA 186 in orbital planes more west of the original one. Indeed, on Dec 17 he recovered USA 186 in a more westward plane.

The new orbit as calculated by Ted Molczan from Greg's orbservations shows that the satellite lowered its orbital inclination by almost a degree, to 96.9 degrees. This manoeuvre probably happened on or near November 12th.

As a result of the inclination change the orbit is no longer sun-synchronous and hence its rate of precession changed. As a result its RAAN is currently shifting westwards relative to the other KH-11's. On December 17 the RAAN of USA 186 had already shifted westwards by 4 degrees. I suspect it will keep precessing until it reaches a value 10 degrees west of what it initially was (see my earlier predictions here, where I predicted this shift in RAAN), close to the aged West plane secondary satellite USA 129 (1996-072A). This shift will have been accomplished by early February at the current rate of precession (0.868 degrees/day or -0.12 degrees/day relative to the sun. Taking into account the RAAN precession of USA 245, they will have a separation of 10 degrees in RAAN by February 5).

USA 186: old orbit (red) and new orbit (white, December 17 plane)

The new orbit is still precessing westward over time. I expect

this will stop once it reaches the RAAN of USA 129 (grey)

I also suspect that next the satellite will reduce apogee altitude to attain a near-circular 390 x 400 km orbit, after which it will be sun-synchronous again. Indeed, the change in inclination to 96.9 degrees indicates as much as this inclination value fits a 390 x 400 km sun-synchronous orbit. As a result, USA 186 would start to move in an orbit very similar to USA 161 (2001-044A) in the secondary East plane in terms of apogee, perigee, inclination and eccentricity as well as in ground-track repeat patterns.

The initiation of these moves comes two months earlier than I expected, suggesting that USA 245 (2013-043A) which was launched into the primary West plane last August 28, needed less check-out time after launch than was the case with USA 224 (2011-002A).

As USA 186 is now moving to take the place of the aged USA 129 satellite, I expect the latter to be de-orbitted any moment.

Below diagram depicts the current constellation (December 17th), with USA 186 on the move westwards between the primary West plane (now occupied by USA 245) and secondary West plane (occupied by USA 129). See my earlier post here for a discussion of primary and  secondary orbital planes.

It will be interesting to see whether the drift in RAAN of USA 186 relative to USA 245 indeed stops at a 10 degree difference (the former separation of the orbital planes of USA 186 and USA 129), or whether it perhaps continues up to 20 degrees (the separation of the orbital planes of USA 161 and USA 224 in the East plane).

Past and future of the KH-11 Keyhole/Evolved Enhanced CRYSTAL constellation (part 4)

In a number of previous posts from the last month (this one being the most pertinent one), I probed the changes to the KH-11 Keyhole/CRYSTAL optical reconnaissance satellite constellation over the past 8 years, aiming to predict what will happen now USA 245  has been added to the constellation on 28 August 2013 (launch NROL-65).

The previous analysis was focussed on the orbital planes of the satellites. In this fourth post in this series, I will take a look at other orbital parameters, such as apogee and perigee heights, eccentricity and mean motion.

West plane KeyHole/CRYSTAL satellites:

 USA 129: launched in 1996,
now in secondary West plane, 
probably soon to be de-orbited?

(imaged 28 Sep 2013)

 USA 186: launched in 2005,
soon to switch from primary West plane to 
secondary West plane?

(imaged  5 October 2013)

USA 245: launched 28 August 2013
into the primary West plane

(imaged 5 October 2013)

Let me first briefly summarize the previous analysis. In these I showed that the KH-11 constellation consists of two primary orbital planes separated by 48-50 degrees in RAAN. In addition, each primary orbital plane has an accompanying secondary orbital plane, 10 degrees more west for the West plane and 20 degrees more East for the East plane.

Satellites are initially launched into one of the primary planes, in their primary mission: after a couple of years, and after a replacement has been launched into the same orbital plane, they shift to the accompanying secondary plane, going from primary mission into secondary extended mission.

For example, USA 129 did this in 2006 after the launch of USA 186; and USA 161 did this in 2011 after the launch of USA 224. I pointed out that I expect USA 186 to do the same early 2014 following the recent launch of USA 245 into the West plane. I also expect USA 129 to be de-orbitted.

The graphic summaries given in that previous post, were these two images (see previous post for discussions):

Shifting from primary to secondary orbital planes is however not the only thing that happens. When we look at various orbital parameters, we can see other, accompanying patterns, notably in the apogee and perigee heights:

(click diagrams to enlarge)

(note: all the orbital parameters used in the diagrams above have been determined by Mike McCants from amateur observations, including mine).


New plane, lower apogee altitudes, and more circular orbit

For example: in the previous post on this topic it was discussed how USA 161 (2001-044A) in the East plane manoeuvred from the primary East plane to the secondary East plane late 2011 by changing its RAAN by 20 degrees (i.e., by rotating its line of apsides). This followed the launch of USA 224 (2011-002A) into the primary East plane, as a replacement for USA 161.

In the diagrams above, we can see that other orbital changes took effect as a result of the same series of manoeuvres. In addition to its orbital plane, USA 161 (blue dots in the diagrams) also changed its orbital eccentricity and its apogee and perigee heights. The apogee height was significantly lowered (which initially confused analysts at the time), from about 960 km to eventually about 390 km altitude. The perigee height was raised somewhat, from 310 km to 390 km altitude. The result is a much more circular orbit.

The inclination of the orbit was also changed, by about one degree. The reason for this can be seen in the lowermost diagram: with the changes in apogee and perigee altitudes, the orbital inclination had to be changed to make the resulting orbit sun-synchronous again.

In all, although much of this was accomplished within 6 months after the massive manoeuvre of late August 2011, it took USA 161 about a year to settle in its new orbit.


A repeat of an earlier case

Earlier, in 2006-2007, changes in the orbit of USA 129 (1996-072A) in the West plane can be seen to follow a somewhat similar pattern.

After the launch of USA 186 (2005-042A) into the primary West plane in 2005, USA 129, by that time already 10 years old and hence quite of age, moved to the secondary West plane by changing its RAAN by 10 degrees. Accompanying this move, is a change in perigee and apogee altitudes. The perigee is gently raised from about 280 km to eventually 310 km altitude. The apogee is lowered from about 1020-1030 km to eventually about 770 km altitude. The orbit becomes much more circular as a result.

With USA 129, this process took much longer than with USA 161 and the changes are less drastic. Yet the ideas behind them are clearly similar to what USA 161 did five years later: change orbital plane from primary to secondary plane, lower apogee significantly, raise perigee gently, and circularize the orbit (although not to the degree like USA 161 later did).

The more gentle approach taken by USA 129 in 2006-2007 compared to USA 161 in 2011-2012 might implicate either of these two scenarios:

(a) USA 129 had less fuel reserves left in 2006 than USA 161 had in 2011;

... or (and I prefer this explanation):

(b) it was anticipated in 2006 that the lifetime of  USA 129 needed to be prolonged untill well after the initial lifetime estimates, putting restrictions on fuel use for manoeuvres.

Remember: this is around the time the KH-11/CRYSTAL follow-up program, the FIA Optical program, entered delays and was next cancelled. So option (b) could well be the case.


What to expect?

Based on these past patterns, I expect USA 186 to do the following things by means of  a series of manoeuvres starting the first months of 2014:

1) change RAAN by 10 degrees (i.e. rotating its line of apsides), moving itself from the primary West plane into the secondary West plane (see previous post here);

2) drastically lower apogee (currently at about 1020 km) to about 390 km altitude;

3) gently raise perigee (currently at 260 km) to about 390 km altitude.;

4) circularize its orbit as a result of (2) and (3);

5) change inclination by about one degree to re-attain sun-synchronicity after the altered apogee and perigee altitudes.

These changes should take a few months and be completed towards the end of 2014. They will likely be initiated by a large manoeuvre early 2014 (in February or March likely).

As mentioned earlier I expect USA 129 to be de-orbited this winter or spring.


Why the apogee and perigee changes?

One question pertaining is: why these changes in perigee and notably apogee? Is a circular ~390 x 390 km orbit easier to maintain? Is there instead some operational reason behind this change in altitudes, in terms of desired track-repeat intervals or equipment performance (e.g. demands of image resolution)? If  so, why are similar changes not made to the orbits of the primary plane objects but only to the secondary plane, extended mission objects? I have no answers, and at best I can speculate from a few ideas I have. That is not for this blog, however.


This post benefitted from discussions with Ted Molczan and Cees Bassa. Interpretations and any errors theirin are mine.