NROL-82: an upcoming new KH-11 EVOLVED ENHANCED CRYSTAL launch [UPDATED]

image: ULA

(updated 27 Apr 2021 with first observational orbit, see end of post)

If the weather and the launch Gods cooperate, ULA will launch a Delta IV Heavy with a classified payload for the NRO on 26 April 2021. The launch is designated NROL-82 and the payload will likely receive the designation USA 314. In a tweet from April 19, ULA mentions a prospective launch time of 20:46 UT.

Several lines of evidence lead us to believe that the payload is a KH-11 EVOLVED ENHANCED CRYSTAL optical reconnaissance satellite, colloquially also known as a 'Keyhole'. It is the kind of satellite that makes these kind of detailed pictures of areas of interest for the NRO.

A map in the ULA Mission Overview for this launch, and the Navigational Warnings issued for this launch (NAVAREA XII 173/21 and HYDROPAC 1221/21) provide information on the launch azimuth and from that the orbital inclination targetted. Likewise the position and time window of the upper stage deorbit area provides - in a very broad sense- information on the orbital altitude aimed for. Together they indicate a launch into a sun-synchronous Low Earth Orbit with an orbital inclination near 98 degrees. This is a very familiar orbit, as we will discuss later in this post.

Below is a map I prepared depicting the hazard areas from these Navigational Warnings as well as the launch trajectory I calculate based on this information:

click map to enlarge

The listed times along the track are for launch at 20:46 UT into the 250 x 1020 km, 97.9 degrees inclined estimated orbit below:

 NROL-82 (USA 314)          for launch on 26 April 2021 at 20:46:00 UT
1 70002U 21999A   21116.86527778  .00000000  00000-0  00000-0 0    03
2 70002 097.8600 222.0898 0548970 157.1680 337.2110 14.78203944    02

 

The text of the Navigational Warnings:

220434Z APR 21
NAVAREA XII 173/21 (also: HYDROPAC 1221/21)
EASTERN NORTH PACIFIC.
EASTERN SOUTH PACIFIC.
CALIFORNIA.
1. HAZARDOUS OPERATIONS:
   A. 2016Z TO 2257Z DAILY 26 THRU 28 APR
      IN AREA BOUND BY
      34-38N 120-40W, 34-36N 120-30W,
      34-07N 120-39W, 34-08N 120-44W.
   B. 2016Z TO 2257Z DAILY 26 THRU 28 APR
      IN AREA BOUND BY
      22-57N 120-46W, 23-47N 125-18W,
      26-27N 124-45W, 25-36N 120-08W.
   C. 2016Z TO 2257Z DAILY 26 THRU 28 APR
      IN AREA BOUND BY
      13-28S 121-20W, 10-47S 138-34W,
      00-47S 136-41W, 03-52S 119-54W.
   D. 2253Z TO 0029Z COMMENCING DAILY
      26 THRU 29 APR IN AREA BOUND BY
      63-14S 174-16W, 32-49S 159-58W,
      33-23S 156-28W, 64-16S 168-07W.
2. CANCEL THIS MSG 300129Z APR 21.

 

Area D from the Navigational Warnings, located in the southern Pacific Ocean, appears to be the deorbit area for the Delta Cryogenic Second Stage (DCSS). The DCSS deorbit takes place some two hours after launch, just after the start of the second revolution (with the deorbit burn happening over the Arctic, near the end of the first revolution).

As mentioned above, the orbit that seems to be targetted is one that is very familiar in terms of orbital inclination and sun-synchronous character. It is the typical orbit of a KH-11 EVOLVED ENHANCED CRYSTAL electro-optical reconnaissance satellite. Several years ago I discussed the KH-11 orbital constellation in depth on this blog ("Past and future of the KH-11 Keyhole/Evolved Enhanced CRYSTAL constellation" - 2013). As a side note, the type of rocket used to launch NROL-82 is consistent with a KH-11 launch too: the Delta IV Heavy has a long history of launching KH-11's.

Currently there are at least three, and possibly four active KH-11 satellites on orbit: USA 186 (2005-042A), USA 224 (2011-002A), USA 245 (2013-043A), and possibly USA 290 (2019-004A).  The latter, USA 290, is in an odd orbit for a KH-11 and its identification as a KH-11 is open to questioning (I will discuss this later in this blog post).

Historically (see "Past and future of the KH-11 Keyhole/Evolved Enhanced CRYSTAL constellation"), new KH-11 satellites are launched into one of two primary orbital planes some 48 degrees apart in RAAN: a "primary East" plane and a "primary West" plane. The time window and the 20:46 UT launch time given by ULA for the upcoming April 26 launch corresponds well with targetting the "primary East" plane. This orbital plane results in passes around local noon and midnight. The KH-11 satellite currently occupying this orbital plane is USA 224 launched 10 years ago in 2011.

 

USA 224 imaged in June 2014. click image to enlarge

KH-11 constellation (minus USA 290), situation mid-April 2021 (polar view). Click to enlarge

 

The orbital plane of USA 224 passes over the launch site of NROL-82, Space Launch Complex 6 (SLC-6) at Vandenberg Air Force Base, around 21:20 UT on April 26. This is a difference of some 35 minutes with the launch time (20:46 UT) from the ULA tweet.

In 2011, when USA 224 itself was launched to replace USA 161 in the primary East plane, the launch occurred some 20 minutes before the USA 161 orbital plane crossed over the launch site (a similar time difference would hence see launch around 21:00 UT for the upcoming April 26 launch).

If history is our guide, the following sequence of event will likely happen. To start with, NROL-82 will be launched into the KH-11 Primary East plane, with an orbital inclination of ~97.9 degrees and orbital altitude of ~250 x 1020 km, almost co-planar with USA 224. The illustration below shows the orbital plane situation around orbit insertion. Note the similarity of the orbital planes of NROL-82 and USA 224:

 

expected situation just after launch of NROL-82. click to enlarge

 

After a check-out period of a few weeks, the NROL-82 payload (likely designated USA 314) will take over the primary plane mission from USA 224, the satellite previously occupying this orbital plane. 

Next, after USA 314 has taken over its role, USA 224 will be moved away from the primary plane, into a new orbital plane with RAAN some 10-20 degrees East of the primary plane: the so called '"secondary East plane". It will also lower its apogee and take up a ~400 km altitude orbit. In this new orbit it will continue to be operational for several years, entering its extended mission phase. 

From this moment on, for the first time since the deorbit of USA 161 in the winter of 2014-2015, all the two primary planes and all the two secondary planes will be occupied by a KH-11 again. The orbital constellation will become something like that in the image below:

Approximate KH-11 constellation after expected rearrangement later this year. Click to enlarge

 

How about USA 290?

You will have noted that after a brief initial mention, I carefully left USA 290, launched in 2019, out of the discussion so far. So what about that object? Is it a KH-11?

USA 290 (2019-004A) was launched as NROL-71 from Vandenberg on a Delta IV Heavy on 19 January 2019 (see an earlier blogpost) and it was suspected by some noted analysts to be a KH-11. It however went into a weird, 73.6 degree inclined ~400 km altitude orbit that is not sun-synchronous and nothing like previous KH-11 orbits. So, had the NRO broken with the previous 'classic' pattern of the KH-11 orbital constellation and were they trying something new?

The identification of  USA 290 as a KH-11 never has been sitting well with me. The odd orbital inclination and non sun-synchronous character of the orbit gives few reasons to think it is an IMINT mission.

In light of the apparent return to the known 'classic' KH-11 constellation with the upcoming launch of NROL-82, I have again started to foster these doubts. Maybe USA 290 isn't a KH-11 after all but something else, something experimental (readers of this blog will have noted that the past 4-5 years, a lot of NRO launches appear to be experimental, going into 'new' previously unseen types of orbit. Some of these are, I suspect, radar imaging satellites).

Ted Molczan has recently suggested that USA 290 is a KH-11, and that its odd orbit is inspired by that of the notorious 'Misty' stealth IMINT satellites of the 1990-ies which were launched in ~65 degree orbits. Basically, he argues that USA 290 is a 'Misty' imaging satellite without the stealth!

I remain agnostic at best about the identity of USA 290. Perhaps, if new payloads are launched into similar orbits over the coming years, the picture will become more clear. For now, I regard USA 290 as an oddity, and not necessarily a KH-11.

UPDATE 27 Apr 2021 11:00 UT

Cees Bassa optically observed the NROL-82 payload on the 2nd and 3rd revolution. Radio observers including Scott Tilley are also tracking it.

Based on a hybrid optical/radio orbit computed by Scott Tilley, the orbital altitude is somewhat different than expected, the orbit less eccentric: but the orbital plane is even closer to that of USA 224.

The orbital plane is very close to that of USA 224 indeed: a ~1 degree difference in RAAN and 0.1 degree difference in orbital inclination.

Orbital altitude currently appears to be about 525 x 760 km, i.e. less eccentric than our initila pre-launch estimate. That of USA 224 is 256 x 997 km.

The NROL-82 payload might manoeuvre in the coming days and weeks in order to have it's apogee and perigee altitudes match with  that of USA 224.

click to enlarge

Imaging a pass of the Crew Dragon Demo-2, and a close fly-by of the Crew Dragon by USA 245! [UPDATED]

click photograph to enlarge

Yesterday May 30 at 19:22 UT finally saw the launch of the SpaceX Crew Dragon Demo-2 with astronauts Hurley and Behnken on board, returning a human spaceflight capability to the USA after nine years of having to hitch rides on a Russian Soyuz.

When the Crew Dragon first passed over the Netherlands some 23 minutes after launch (see map with the launch trajectory in  a previous post), the sun was still just above the horizon for my Leiden location. I nevertheless tried with binoculars, using the moon as a guide, but saw nothing.

But two hours after launch on the second revolution, near 21:18 UT, we did have a visible pass, albeit in late twilight and very low above the horizon: at a maximum elevation of only 9 degrees over the horizon and a range of almost 1200 km!

To observe this pass I went by bicycle to Cronesteyn Polder at the edge of Leiden, where I have an uninterupted view to the horizon, and set up my photo camera. First, at 23:14 local time (21:14 UT), I saw the ISS pass with the naked eye low on the southwest horizon. I then took to binoculars and waited for the Crew Dragon, which should pass somewhat lower in the sky some 4 minutes after the ISS.

I picked the Crew Dragon up in my 10 x 50 binoculars starting around 21:17:30 UT, while it was passing through Crater and Corvus. I watched it untill it entered Earth shadow at about 21:19:00 UT. It was not particularly bright, due to the low elevation and still bright sky background. By comparison to stars in Corvus I estimate it to have been magnitude +3 to +3.5, too faint at this elevation and with this sky brightness to be seen naked eye. It was at a range of almost 1200 km at that time, over Northern Spain!

Click photograph to enlarge

The image above shows the Crew Dragon during this pass. It is a stack of 45 exposures of 0.5 seconds each, with a Canon EOS 80D and SamYang 1.4/85 mm lens at F2.0, 500 ISO, 21:17:40 - 21:18:09 UT (May 30). Stars in the image belong to the constellations Crater and Corvus. The small breaks in the trail are the brief moments between the successive photographs that make up the stack.

The image below is another stack, this time of 52 photographs with the same camera setup, made between 21:18:25 - 21:18:59 UT. You see the Crew Dragon disappear in Earth shadow at the left end of the image. The image is slightly wobbly - my tripod was on a soft grassy surface. I like this image best though:

Click photograph to enlarge

It was pretty cool seeing the Crew Dragon, while knowing it was carrying two astronauts!

But it becomes even more interesting: in two images around 21:18:19 UT, I have another brighter satellite moving under a slant upwards in the opposite direction. You can see it in the upper right corner of this image (several lay observers saw this brighter satellite too and mistook it for the Crew Dragon):

Click photograph to enlarge

This object is the classified US KH-11 spy satellite USA 245 (2013-043A).

And as it turns out, it was really close to the Crew Dragon, and my image truely captures, within a few seconds, the actual moment of closest approach! This was serendipity, as I had not planned this and the presence of USA 245 took me by surprise.

Nominally, the minimum distance between USA 245 and the Crew Dragon during this fly-by was only 125 km with closest approach happening at 21:18:17 UT. USA 245 was flying this distance 'above' the Crew Dragon. Both objects were over northern Spain around the time of the flyby, with the point of closest approach over 43.40 N, 2.50 W, on the Basque coast.

There is some uncertainty in the actual fly-by distance (see below), but not much.

This is the output from a COLA analysis for this fly-by:

DATE      UT          SSC   NAME    TARGET      KM  
5/30/2020 21:18:16.99 39232 USA 245 CREW DRAGON 125.3

My analysis is based on CSpOC elset epoch 20151.85044152 for the Crew Dragon, and amateur elset 20146.86101776 for USA 245. There is some leeway in the exact time and distance of the flyby, for two reasons:

1)  from my observations, the Crew Dragon was some 3 seconds late on the used elset;

2)  the USA 245 elset epoch, based on amateur observations that include my own, was 5 days old. However, the sky position of USA 245 in the image is very close to the ephemeris, so the 5-day-old orbit nevertheless seems a good fit to reality.

Taking these points into account, I estimate that the uncertainty in the minimum distance between both objects is no more than 30 km, and only a few seconds in time.

In the map below, I have plotted the trajectories of both objects (I have accounted for the fact that the Crew Dragon was ~3 seconds behind on the elset in this map). USA 245 was moving nortwest-wards, the Crew Dragon southeast-wards.

Note that the USA 245 trajectory was situated some 125 km above that of the Crew Dragon. So to be clear, there was no danger of a collision. This is a safe distance.

click map to enlarge

 This is an animation of the close fly-by:




In fact, it could very well be that this close flyby was intentional, and that USA 245 was actually imaging the Crew Dragon at that moment.

USA 245 is a KH-11 electro-optical reconnaissance satellite: a satellite that resembles the Hubble Space Telescope and makes high resolution images of the earth surface (similar to this infamous one) with resolutions of 10 cm or better.

There have long been rumors, reported by amongst others NBC News, that KH-11 satellites were used to inspect the outside of Space Shuttles post-launch (e.g. that of the inaugural STS-1 flight) for tile damage. We also suspect that KH-11 satellites inspect X-37B's after launch, based on the odd jumps in launch times of the latter (see this analysis by Bob Christy).

So there is a real possibility that this close flyby of the Crew Dragon by USA 245 was intentional, and used to image the spacecraft to see if it was not damaged and everything deployed as it should.

UPDATE 1 June 2020 13:50 UT:

I am retracting the notion of intentionality of this encounter. Both Michael Thompson and I have done an extended analysis of potential KH-11 encounters with the Crew Dragon, where we looked at potential encounters had the Crew Dragon launched on the original launch date of 27 May.

There appear to have been no particularly close encounters would the Crew Dragon have launched on May 27, which calls into question the intentionality of the encounter on May 30.

That said: it is still possible that imaging of the Crew Dragon took place, as of course this would have been a perfect opportunity. I guess we'll never know. Unless, as someone put it to me in private, tongue in cheeck: "if they put it in a briefing, maybe Trump will tweet about it!". 

The analysis also found a second close encounter for May 30, with the KH-11 satellite USA 224 (2011-002A), on 30 May 20:07:50 UT, some 45 minutes (half a revolution) after launch, with a nominal miss distance of 105 km. This however was a pass where the Crew Dragon was in Earth shadow, so not illuminated (which does not preclude infra-red imaging however). COLA output for this encounter:

DATE      UT          SSC   NAME    TARGET      KM 
5/30/2020 20:07:50.30 37348 USA 224 Crew Dragon 105.4

USA 290 (NROL-71)

click image to enlarge

The photograph above is not the best of images, but it does show the trail (faint) of  USA 290, the payload of the January 19 NROL-71 launch from Vandenberg. I shot it last Monday morning, February 11th.

I wrote about this odd launch earlier (here). Before the launch, it was widely suspected that this was a new electro-optical reconnaissance satellite, a block V KH-11 ADVANCED CRYSTAL ("Keyhole"). So we expected it to go in a 98-degree inclined, ~1000 x 265 km sun-synchronous orbit, the orbit typical for new primary plane additions to the KH-11 constellation.

But then the Maritime Broadcast Warnings for the launch came out, and it became clear that the splashdown and deorbit zones did not fit a launch azimuth consistent with such an orbit (see a previous post where this was discussed). Instead, it suggested a 74-degree inclined, 265 x 455 km non-sunsynchronous orbit. Which was very odd, as it was completely against expectations for a new KH-11.

click map to enlarge

The launch was postponed several times, but finally happened on 19 January, a month later than it was originally slated. The launch postponements added a new mystery: the shifting launch window times with each postponement suggested a particular orbital plane with a nodal precession of -2.27 deg/day was aimed for.

The question was: why, if  NROL-71 was going into a 74-degree inclined orbit? Targetting a specific orbital plane only makes sense when the payload is part of a constellation of satellites. But NROL-71 was not targetting the orbital inclination of the existing KH-11 constellation (currently consisting of USA 186, USA 224, USA 245). And it's orbit is (as we will see) not sun-synchronous. It is very odd (and does suggest there will be future objects going into a similar orbit).

After launch on 19:10 UT on January 19th, 2019, there initially was no optical visibility as nighttime passes in the Northern hemisphere were in earth shadow.

But radio observers (a.o. Sven Grahn, Scott Tilley, Cees Bassa, Nico Jansen) quickly picked up the radiosignals of the payload at 2242.5 MHz. These showed that the payload was in a 73.6 degree inclined non-sunsynchronous ~400 km Low Earth Orbit, much as we had gleaned pre-launch from the hazard zones in the Maritime Broadcast Warnings.

As USA 290 slowly emerged from Earth shadow passes, the first optical observations were made by Russell Eberst in Scotland in the morning of 1 February. Next Leo Barhorst in the Netherlands soon followed.

These initial passes were very low in the sky, too low for my urban environment where I need elevations above 20-25 degrees to clear the rooftops. And when as February progressed the passes gradually climbed higher in the sky for my location, weather was not cooperating.

But in the morning of 11 February I finally had a clear sky, and managed to image USA 290, photographically as well as on video. As the illumination angle was not the best, the payload stayed a bit faint, but still was bright enough to register as a faint trail on the photograph (the bright star near the trail is gamma Cygni. Image taken with a Canon EOS 60D + EF 2.0/35 mm lens):

click image to enlarge

The object showed up well on the video (WATEC 902H + Canon FD 1.8/50 mm lens), yielding good astrometry:




The optical observations helped to better define the orbit. They show USA 290 is in a 393 x 422 km, 73.6 degree inclined, non-sunsynchronous orbit.

Apart from abandoning the 97.9 degree inclined sun-synchronous orbit of the primary plane KH-11's, it also abandoned the 1000 x 260 km orbital altitude that was previously typical for new primary plane launches. The orbital altitude is closer to the extended mission, secondary plane KH-11's, the sole representative of which (USA186) currently is in a 262 x 452 km orbit.

Of course, in terms of orbital inclination and nodal precession (the non-sunsynchronous character) it doesn't compare to any of the previous KH-11.

(Note: a few year ago I wrote a series of detailed posts analysing the orbital constellation of the KH-11, and the typical changes in orbital plane and orbital altitude when a new addition to the constellation was launched: see the posts here and here).

click to enlarge

click to enlarge

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So, there is something new under the sun, in more than one way. While the general consensus still is that USA 290 is an electro-optical bird in the ADVANCED CRYSTAL lineage, the radical break with previous orbital structures for this series of satellites is highly interesting. It will be interesting to follow this new object, and see how things develop with future launches.

Over the last two years, the black space program in Low Earth Orbit has become much more exciting, with some new eyebrow-raising additions unlike any previous missions. Examples are USA 276, the failed Zuma launch, and now USA 290, all launches from the past 1.5 years.

I like it: just when we thought things were getting perhaps a tad predictable, we are suddenly treated to a number of surprises, resulting in new stuff to ponder and analyse.

USA 224 recovered: an update of the KH-11 constellation

Russell Eberst in Scotland has recovered the noon-plane KH-11 ADVANCED CRYSTAL/"Keyhole" optical reconnaissance satellite USA 224 (2011-002A) this week. The recovery happened relatively late (in 2015 it was recovered 2 months earlier).

This recovery means that, after the preliminary update last March, I can provide my periodic update on the orbits of the KH-11 constellation based on timely orbital data.

In various previous post to this blog, I outlined how the KH-11 constellation consists of two primary orbital planes, the primary East and West planes; and originally two, now one, secondary orbital plane(s). Of the latter secondary planes, only one, the secondary West plane, is left after the de-orbit of USA 161 late 2014.

The past decade or so, the primary planes have been 48-49 degrees apart in RAAN. That is still the case: USA 224 and USA 245, the primary East and West plane KH-11's, are currently 49 degrees apart in RAAN.

The secondary planes used to be either 10 or 20 degrees from the corresponding primary plane in RAAN, but since mid-2014 the secondary West plane (currently USA 186) has moved further out, to 24 degrees West of the primary orbital plane.

As I have outlined before on this blog, the secondary plane(s) differ in orbital altitudes from the primary planes. The current configuration:


         perigee   apogee    l time   repeat
Sat        km        km      d node   (days)   plane
USA 186    261       454     08:05      3      secondary W
USA 224    262      1007     12:58      4      primary E
USA 245    266      1000     09:42      4      primary W

Given are the apogee and perigee altitudes of the satellites, the average local time they pass through their descending node (an indication of around what time they pass a given area - all satellites in the constellation are sun-synchronous, i.e. they pass  at a similar solar elevation each day), the repeat interval of the ground track in days, and the plane they orbit in.

What can be seen is that the secondary plane satellite, USA 186, is in a much more circular orbit with a much lower apogee (454 km), compared to the two primary satellites (~1000 km). Perigee altitudes of all three satellites are similar. I have speculated on the reason for this apogee difference of the secondary plane satellite at the end of a previous post.

The West plane satellites, USA 186 and USA 245, make morning passes, about 1h45m after each other. The East plane satellite, USA 224, makes passes about an hour after local noon.

The current orbital configuration has been more or less stable since mid-2014 (or more exactly, since USA 161 was de-orbitted late 2014).

USA 186 rising, and revisiting the KH-11 constellation

click image to enlarge

The image above shows the KH-11 ADVANCED CRYSTAL/"KeyHole" optical reconnaissance satellite USA 186 (2005-042A) rising over the roof of my house in late twilight of March 28, 2016.

It had passed perigee at 260 km altitude just 10 minutes earlier and was at about 285 km altitude when I photographed it. At that low an altitude, it races over the sky (these are 5 second images with a 50mm lens). Clearly visible by the naked eye, I watched it rise over the roof, and then slowly flare to mag. -1 near 19:17:55 UT:

USA 128 186 flaring near 19:17:55 UT (March 28, 2016)
click image to enlarge

USA 186 is the oldest of the remaining KH-11 ADVANCED CRYSTAL satellites. After the de-orbit of  USA 161 late 2014, there are now three KH-11's left on-orbit:  

(a)  USA 186  (2005-042A) pictured here;
(b)  USA 224  (2011-002A), and;
(c)  USA 245  (2013-043A).

USA 224, the primary East plane satellite, and USA 245, the primary West plane satellite, are separated by 48.7 degrees in RAAN. USA 186, the secondary West plane satellite, is 24.3 degrees (half the separation of the two primary satellites) West of USA 245 in RAAN:

click to enlarge

All the orbits are sun-synchronous, meaning that they maintain an orbital precession coupled to the daily precession of the sun.This ensures that they make passes at roughly the same time each day, imaging terrain with roughly similar solar elevations. This helps interpret imagery, as the shadow patterns will be similar on images from nearby days and changes in shadow pattern will stand out.  

USA 224, the primary East plane satellite in the constellation, makes daily passes around 13h local solar time. It's ground track repeats each 4 days. USA 245, the primary West plane satellite, makes daily passes around 9:45h local solar time, also with a ground track repeating each 4 days. USA 186, the secondary west plane satellite, makes daily passes around 8h local time, with a repeating ground track each 10 days.

Basic data ():

sat      orbit           mlt DN    repeat  plane 

USA 124  265 x 1009 km*  13:00     4 days  primary E
USA 245  268 x 1020 km   09:45     4 days  primary W
USA 186  260 x 456  km   08:05    10 days  secondary W

* September 2015 (sat not yet recovered in 2016)

("mlt DN" means mean "local time of passage through Descending Node") 

Note that due to the winter blackout in the Northern hemisphere we haven't observed USA 224 for seven months: the orbit shown here assumes it has kept up its September 2015 orbit. We will know for sure when we recover the object in early summer.

The previous secondary West plane satellite in the constellation, USA 129 (de-orbited in late April of 2014) used to make passes near 9h local time. By changing the RAAN difference between the primary and secondary satellite from 10 degrees to 24.3 degrees after USA 186 moved from the primary to the secondary plane and took over from USA 129 following the launch of USA 245 (see earlier post here and links theirin), the pass time was shifted to one that occurs one hour earlier.

As can be seen in the table above, all current KH-11's have perigee at a roughly similar altitude of ~260-270 km. The primary plane satellites have apogee at ~1010-1020 km. The secondary plane satellite has a much lower apogee, at ~455 km altitude.

The exact reason why the secondary plane KH-11's lower their apogee is unclear. USA 129 was the first to lower apogee connected to its move from the primary West plane to the secondary West plane in 2006. USA 161 repeated this pattern in 2011 when it was moved from the primary East plane to the secondary East plane (since the de-orbit of USA 161 late 2014, this latter secondary East plane no longer exists). Various options can be considered:

(a) some operational constraint, e.g. aim for a particular ground-track repeat interval;

(b) some operational constraint, e.g. related to image resolution (this is unlikely);

(c) some operational constraint, e.g.different imaging role compared to the primary plane satellites;

(d) making it easier to de-orbit the satellite near end-of-life: if fuel reserves are low, a lower apogee would allow de-orbit from apogee if necessary, so one does not necessarily have to wait for perigee to be located over the southern Pacific.

KH-11 USA 186 has stabilized its orbit

Note 15/09/2014 9:25 UT: corrected inadvertent apogee - perigee mix-up in 4th paragraph

USA 186 passing in early twilight of the evening of Sept 12, 2014
(click image to enlarge)

At the end of May, Northern hemisphere observers lost visibility of KH-11 Keyhole/CRYSTAL USA 186 (2005-042A) when the midsummer nights became too short. The orbital plane of the satellite was still drifting at that time, a process that started after a manoeuvre in mid-November 2013 (see earlier posts on this blog). The big question was, when that drifting would stop. I expected that when the satellite reached its new intended orbital plane it would manoeuvre into a stable sun-synchronous orbit again.

It now has done so, having manoeuvered probably on or near July 1. The orbital plane drift has stopped.

Kevin Fetter in Canada made a chance recovery of the satellite, the first post-summer glare-out sighting, on September 8: he was looking for another object and saw a "unid" in Low Earth Orbit pass through his field of view, that Cees Bassa was quick to identify as USA 186, in a new orbit. Over the next nights several other observers tracked it (including me on Thursday and Friday evening) yielding a first version of the new orbit it is in.

USA 186 passing close to Arcturus (top left) in the evening of Sept 11, 2014
(click image to enlarge)

The satellite has drastically lowered its perigee apogee by almost 500 km, and gently raised its apogee perigee by a few km. It is now in an approximately 265 x 440 km, 96.9 degree inclined orbit. This orbit is sun-synchronous again.

This means that the RAAN drift relative to the other satellites in the KH-11 constellation that had been going on since mid-November 2013, has stopped. It has finally settled at a RAAN distance of about 25 degrees from USA 245 (2013-043A), the primary West plane KH-11.

Comparing the new orbit to the old orbit suggests that the manoeuvre into the new orbit happened on or near July 1st.

In all, the satellite has kept itself pretty much to the expected scenario which I outlined on this blog in several posts in September and October 2013, e.g. here and here. Following the launch of USA 245 (2013-043A) into the primary West plane of the KH-11 constellation in August 2013, I had predicted that:

1) USA 186, at that time the primary West plane satellite, would migrate its orbital plane to the secondary West plane; 

2) USA 129, the extremely aged satellite in the secondary West plane, would be de-orbitted;

3) after a period of drifting, USA 186 would manoeuvre back into a sun-synchronous orbit again, stopping the RAAN drift, when reaching the intended plane location of the secondary West plane;

4) that in that manoeuvre it would drastically lower its apogee from near 1000 km to near 400 km and gently raise its perigee.

This all has basically happened. It differed on details with my predictions, but the bigger picture is pretty much as I anticipated.

What was somewhat unexpected, is that the satellite had its RAAN drift to a much larger distance with respect to the primary West plane (now occupied by USA 245) than I had anticipated. I expected 10, maybe 20 degrees. It turned out to be almost 25 degrees.

The perigee, although indeed raised, is slightly lower than I expected. The massive lowering of the apogee is exactly how I expected it to be however.

The current orbital plane makes it make passes near 8 am and 8 pm local time.

Meanwhile, there are indications that USA 245 (2013-043A) in the primary West plane has manoeuvered. Russell Eberst still observed it in it's last known orbit from Scotland on Sep 7. Then Bjorn Gimmle from Sweden observed an unknown object on Sep 10, that I suspect is USA 245 after a perigee raising orbital manoeuvre conducted between Sep 7 and Sep 10.

[note 14/09/2014: Mike McC identified Bjorn's object as a Russian r/b near decay]
[note 15/09/2014 9:25 UT: corrected inadvertent apogee - perigee mix-up in 4th paragraph]

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.

KH-11 USA 129 is missing, USA 186 has still not manoeuvered

USA 129 (96-072A), the oldest of the KH-11 Keyhole/CRYSTAL/KENNAN optical reconnaisance satellites, has gone missing. The last observers to see it were me on April 22 and Russel Eberst on April 24. The photo below shows one of my images from April 22, with USA 129 passing near Castor and Pollux:

click image to enlarge

Somewhere between that date and May 1, when various observers noted it missing, it disappeared.

There is a possibility that it has been de-orbitted, as it is over 17.5 years old now and appears to be 'redundant' after the launch of USA 245 and plane move of USA 186 (see various earlier posts on this blog). On the other hand, we should be cautious and not too hasty: in the recent past (Feb 2014) we erroneously wrote USA 129's eulogy before, and it turned out it had just manoeuvered. Maybe it did this time as well. A dedicated plane watch I did in the evening of 3 May between 20:41 -21:05 UT yielded nothing.

Meanwhile, we had expected USA 186 (2005-042A) to manoeuvre early May. But up to yesterday May 4th it hasn't. Maybe it will do in the coming days. On May 1st the difference in RAAN with the main West plane KH, USA 245, was 19.8 degrees. At a drift rate of 0.11 degrees/day, it reached 20 degrees the past weekend. If it hasn't manoeuvered by the end of the coming week, it will become interesting. Unfortunately, it is disappearing in evening twilight for my location these days.

The image below shows USA 186 crossing Canis minor in deep evening twilight of May 2nd:

click image to enlarge

I imaged USA 245 (2013-043A), the current main West plane KH-11, last Saturday evening. In evening twilight, it was visible in the same camera field with FIA Radar 1 (2010-046A):

click image to enlarge

A flare show by USA 245

Wednesday evening saw a dynamic atmosphere, where clear skies intermittently were broken by fields of fast moving scattered clouds.

I targeted all three West plane KH-11 Keyhole/CRYSTAL satellites that evening: USA 129 (1996-072A), USA 186 (2005-042A) and USA 245 (2013-043A).

USA 245 had a pass during a period where patches of clouds occupied the southern sky up to the zenith. The image below shows it rising through Leo, over the roof of my house, amidst scattered clouds:

click image to enlarge

USA 245 twice flared brightly during this pass. Such flares are caused when a reflective surface on the satellite (solar panels, an antenna panel, a dish or some other part of the structure) acting like a mirror reflects sunlight directly towards the observer. I love it when they do that, it is always spectacular.

The first flare was a slow bright one up to magnitude -2 peaking near 20:27:28 UTC (26 March) just above the back of Leo:

click image to enlarge

One-and-a-half minutes later at 20:29:03.64 UTC, while passing through Uma, it flared again, a more brief glint/flare to magnitude -1:

 click images to enlarge

USA 129 was also observed, low in the west while emerging from earth shadow. It only faintly registered on one image, allowing one position determination. USA 186 was not seen, but this was likely due to unfavourable circumstances (it was too faint for the lens used) as Cees Bassa did observe it, on-time, the next day.

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).