Past and future of the KH-11 Keyhole/Evolved Enhanced CRYSTAL constellation (part 3)

In my previous post I outlined in detail how information gleaned from past changes in the KH-11 Keyhole/CRYSTAL optical reconnaissance satellite constellation might yield a blueprint for changes to be expected in the coming months, following the launch of USA 245 (NROL-65, 2013-043A) into the same orbital plane as USA 186 (2005-042A) last August 28.

click image to enlarge

That discussion involved a look at past configurations, especially the relative positions of the orbital planes of the primary and secondary satellites in the constellation. Based on these past configurations, I concluded:

"After these orbital re-arrangements, USA 224 and USA 245 will be the primary satellites in the East resp. West plane. If history is to go by, their orbital planes will likely be separated by about 48 to 50 degrees. The orbital plane of the secondary East plane satellite, USA 161, will probably be 15 to 25 degrees east from that of USA 224. The orbital plane of USA 186, now the secondary satellite in the West plane, will most likely eventually be located 5 to 15 degrees west from that of USA 245."

This weekend I mapped the history of the KH-11 constellation in somewhat more detail than I did for my previous post (where I only looked at 2007, 2011 and 2013). Based on this more detailed analysis, I think I can constrain the distribution of orbital planes even further. The orbital plane of the secondary West plane satellite, a role USA 186 will take early 2014 if I am correct, will be located 10 degrees west of the primary West plane satellite. The orbital plane of the secondary East plane satellite, USA 161, will maintain to be located 20 degrees west east of the primary East plane satellite.

I can say this with some confidence because this seems to have been the intended nominal KH-11 constellation over the full past 8 years.

Since 2005 I keep an archive of the frequently updated classfd.tle orbit files calculated by Mike McCants: they are based on amateur observations that include mine. From my archives I extracted orbital elements for the KH-11 Keyhole/CRYSTAL satellites with an epoch in early July, for each year between 2005 and 2013. Next, since the orbit epochs in question sometimes differ by a few days, I used Scott Campbell's SatFit software to normalize them all to the same epoch, day yy182 (where yy is the year and 182 is the day number), i.e. July 1st of each year.

By normalizing to the same epoch, the RAAN values of the orbits become directly comparable. RAAN stands for Right Ascencion of the Ascending Node, and this value maps the orientation of the orbital plane in space for the epoch in question. More precisely, the RAAN value gives the angle of the orbital plane in earth-centered space, with respect to the direction of the Vernal equinox at the epoch in question.

click diagram to enlarge

The diagram above maps the RAAN values (in degrees) at July 1 for each KH-11 satellite in each year in the period 2005-2013. The diagram below plots the same data, but then expressed as the difference delta (in degrees) between the planes of the primary East and West plane satellites, as well as the delta between the planes of the primary plane satellites and the secondary plane satellites:

click image to enlarge

A clear systematics can be seen to it. The primary East and West plane satellites (always the newest satellite in each plane) are 48 to 50 degrees apart. The secondary West plane satellite is in an orbital plane 10 degrees more westward than the primary West plane satellite. The secondary East plane satellite is in an orbital plane 20 degrees more eastward than the primary East plane satellite.

These are (of course) similar values to what I reported before, but now much more clearly constrained, documented over a larger time span, the diagrams visualizing the intended spatial arrangement very well. An arrangement that has basically been stable over the past 8 years. Changes in the arrangement amount to satellites switching roles (and orbital planes), but the basic orbital planes that make up the constellation remain the same.

The top diagram visualizes how satellites have switched from primary to secondary roles (and from orbital plane) as new satellites are added to the constellation.

For example, we see USA 129 (1996-072A) switch from the primary West plane to the secondary West plane in 2006-2007, following the launch of USA 186 (2005-042A) into the primary West plane. It does so by changing its orbital plane by 10 degrees. And we see USA 161 switch from the primary East plane to the secondary East plane in 2011-2012 (actually late August 2011), following the launch of USA 224 into the primary East plane. It does so by changing its orbital plane by 20 degrees.

A similar switch will no doubt occur early 2014 (see my previous post), when (if I am not wrong) USA 186 switches its orbital plane by 10 degrees from the primary West plane to the secondary West plane, once USA 245 (freshly launched into the primary West plane last August 28) becomes fully operational.

What can also be seen, is how USA 116 (1995-066A) started to drift away from its orbital plane after 2006, and was next de-orbited in 2008. The suggestion is that this satellite had almost ran out of fuel by 2006, as a result of which it was no longer an option to counter the drift by periodic manoeuvres. By 2008 it was drifting too far from the intended constellation, and the last fuel reserves were then used to de-orbit it. The secondary East plane was then left empty until three years later, in 2011, USA 161 (2001-044A) took on the role previously filled by USA 116. This happened after USA 224 (2011-002A) was launched as a replacement into the primary East plane. As of late 2011, the KH-11 constellation can hence be considered complete again (I have pointed out earlier, in my previous post, that the 2008-2011 gap in the secondary East plane was caused by the delay and then cancelling of the FIA optical program).

Note 12 Oct 2013: a follow-up on this post, discussing other orbital parameters than orbital plane, can now be read here.

On USA 245 and USA 129, and the future of the Keyhole constellation: an afterthought to my previous post

In my previous post I discussed how the new KH-11 Keyhole/CRYSTAL USA 245, launched as NROL-65 on August 28,  has been inserted into the same orbital plane as USA 186, a KH-11 launched in 2005. I also discussed the current KH-11 Keyhole/Evolved Enhanced CRYSTAL optical reconnaissance satellite constellation in that post.

Near the end of my post, I wrote:

"With the optical component of the FIA program cancelled, I suspect all of the remaining post-1996 Keyholes to remain operational for many years. For USA 129 though, the end should come one of these days, perhaps once USA 245 has been fully checked out and is put on operational status."

I have since formulated some more thoughts about the likely timetable and likely sequence of events, which are the topic of the current post.


Current and past KH-11 constellations

The KH-11 optical reconnaissance satellites occupy two orbital planes, a West and an East plane. I have already written about this before in my previous post. The image below (made with JSatTrak) gives a graphic depiction of the KH-11 constellation for early September 2013:

 click image to enlarge

With the addition of USA 245 on August 28, the West plane now consists of three satellites:

USA 129  (1996-072A)  operational, but near operational end?
USA 186  (2005-042A)  operational
USA 245  (2013-043A)  new addition being readied for operation

As I wrote before, USA 129 (1996-072A), the oldest KH-11 still on orbit, is now near an incredible 17 years of operational lifetime. With this, it has had by far the longest life-time of any KH-11 so far (see Ted Molczan's KH-11 lifetime data compilation here).

The East plane consists of two satellites:

USA 161  (2001-044A) operational
USA 224  (2011-002A) operational

A previous satellite in the East plane, USA 116 (1995-066A) was de-orbited in November 2008, some 7 years after USA 161 was added to that orbital plane. This was probably done because it had reached the end of its feasible lifetime (for example, because it was running out of fuel, or because vital components started to deteriorate). It had been operational for 13 years when de-orbited.

With the launch of USA 224 on 20 January 2011, slightly over two years later, the East plane was fitted with a second satellite again. This launch probably came so late, because the new FIA Optical program was originally supposed to take over from the CRYSTAL/KH-11 program by 2008. The FIA Optical program was however delayed and then cancelled, and the KH-11/CRYSTAL program reinvigorated.

The cancelling of the FIA Optical program, leaving the KH-11/CRYSTAL program without a follow-up, is why I think that the remaining Keyholes will remain in orbit for several more years, except for the exceptionally aged USA 129. The KH-11 Keyhole/CRYSTAL satellites are currently the only high-resolution optical reconnaissance satellites available to the NRO, apart from time hired on commercial imaging satellites (DigitalGlobe).

If the lifetime of USA 129 is a guide, the remaining operational KH-11 lifetimes will perhaps be up to five more years for USA 161, perhaps up to ten for USA 186, and perhaps up to 15 years or even more for USA 224 and USA 245.


Re-arrangements after the USA 224 launch in 2011

The history of the previous addition to the KH-11 constellation in 2011 might constitute a blueprint of what will happen the coming months, now USA 245 has been added to the constellation.

In 2011, USA 224 was initially launched into the same orbital plane as USA 161, similar to how USA 245 has now been launched into the same orbital plane as USA 186. A few months after the USA 224 launch the older East plane satellite (USA 161) manoeuvered to a lower orbit (or more accurately: a more circular orbit with lower apogee), on 24 August 2011. This was preceded by a number of smaller preparatory manoeuvres in the previous two months according to Ted Molczan (priv. com.).

This could indicate that USA 224 became fully operational about 5 to 7 months after launch. At that moment it became the primary satellite in the East plane, with USA 161 next taking on a new secondary role in an extended mission, as indicated by its manoeuvre into a different orbit.

Subsequently, the orbital plane of USA 161 was allowed to drift slightly eastward. As a result, the orbital plane of the older USA 161 in the East plane is currently located 20 degrees east of that of the newer USA 224,  in a similar vein as the orbital plane of the older USA 129 in the West plane is located somewhat westward of that of the newer USA 186.

(note: the saga of the significant August 2011 manoeuvre of USA 161 and its eventual recovery by observers including me, has been covered on this blog here, here and here).


Current and past plane separations

The orbital planes of the current main West plane satellite, USA 186, and the main East plane satellite, USA 224, are some 48 degrees apart. Likewise, before USA 224 took over from USA 161 mid-2011, the orbital planes of the then main West and East plane satellites USA 161 and USA 186 were 49 degrees apart. Mid 2007, the then main East and West plain satellites USA 161 and USA 186 were 50 degrees apart. This is all very similar, differing by only 1-2 degrees.

click image to enlarge

The orbital plane of the secondary West plane satellite, USA 129, is currently located 10 degrees west of the plane of the primary West plane satellite USA 186. The orbital plane of USA 161, the secondary satellite in the East plane, is located 20 degrees east of the orbital plane of the primary East plane satellite USA 224. Mid 2011 this was 2 resp. 12 degrees, and mid 2007 it was 5 resp. 26 degrees.

In table form, for the current constellation (September 2013):

Epoch 13250   
7 Sept 2013
 
----------------------------------------- 
satellite  RAAN    PER   APO   incl   
(name)     (deg)   (km) (km)   (deg)
-----------------------------------------

WEST PLANE

USA 129    303     308   770  97.56   S 
USA 186    313     262  1017  97.94   P
USA 245    314     262  1010  97.87   fP

EAST PLANE
   
USA 224    01      258  1023  97.88   P
USA 161    21      385   393  97.03   S
-----------------------------------------

P  = Primary
fP = future Primary
S  = Secondary


(In this table, RAAN stands for Right Ascension of the Ascending Node. This value determines the position of the orbital plane in earth-centered space with reference to the vernal equinox point at the epoch in question. PER and APO refer to the altitude of Perigeum and Apogeum, and incl is the orbital inclination. See also here. All data are based on orbital elements calculated by Mike McCants from amateur observations, including mine).

I do not know what the reason is for the asymmetry between the secondary East and West planes with relation to their primary planes (10 resp. 20 degrees currently), although I suspect it has to do with  solar angles at the imaged target locations (the West plane satellites pass in the morning, the East plane satellites somewhat after noon).


Future re-arrangements and expected USA 129 de-orbit

If the pattern after the addition of USA 224 in 2011 repeats in the West plane with USA 186 and the newly added USA 245, I expect USA 245 to become fully operational around February 2014. Around that time it will become the primary satellite in the West plane. Between  now and then, it will probably make more manoeuvers to finalize its intended orbit.

We can then next also expect USA 186 to attain a new secondary role and go into a new extended mission, by manoeuvering into a more circular orbit with lower perigee apogee somewhere in February or March 2014. Next, the orbital plane of USA 186 will probably be allowed to drift somewhat westward, as a result of which USA 186 will take up an orbital plane slightly west of that of USA 245.

Near that same time, and possibly somewhat earlier if time is really running out on it, we might see the de-orbit of USA 129.

After these orbital re-arrangements, USA 224 and USA 245 will be the primary satellites in the East resp. West plane. If history is to go by, their orbital planes will likely be separated by about 48 to 50 degrees. The orbital plane of the secondary East plane satellite, USA 161, will probably be 15 to 25 degrees east from that of USA 224. The orbital plane of USA 186, now the secondary satellite in the West plane, will most likely eventually be located 5 to 15 degrees west from that of USA 245. The  orbital planes of the outer (secondary) East plane and outer (secondary) West plane satellites, USA 161 and USA 186, will probably be separated by about 80 degrees.

(note added 15 Sept 2013: after a more comprehensive analyses of the orbital planes over 2005-2013, I believe the orbital plane of the secondary satellite in the West plane to be placed 10 degrees west of the primary West plane: and the orbital plane of the secondary satellite in the East plane to be placed 20 degrees East of the primary East plane. See my follow-up post here)

Of course, these are all just no more than educated guesses, based on past configurations and re-arrangements of the Keyhole/CRYSTAL constellation. Time will tell us whether this scenario will indeed play out as I outlined above. It is always possible that we will eventually see something completely different!


Sun-synchronous, repeating ground tracks

KH-11 Keyhole/CRYSTAL satellites move in sun-synchronous orbits that have their ground tracks more or less repeat after an integer number of days (1, 2, 4 or more days). The goal is to obtain comparative images of the same location taken a few days apart, taken with similar illumination by the sun (i.e., similar shadows). This aids the analysis of the images for the detection of any changes on sites of interest.

As I wrote in my previous post, the West plane Keyhole/CRYSTAL satellites make evening and morning passes. The East plane Keyhole/CRYSTAL satellites make passes 1-2 hours after local noon and midnight.

USA 186 and USA 224, the current primary satellites in the West resp. East plane, repeat their ground tracks after 4 days (the 4:59 resonance). USA 129 and USA 161, the secondary satellites in the respective planes, repeat ground tracks after 12 resp. 7 days.

When USA 245 has taken over from USA 186 in the West plane by February-March 2014, we can expect it to have a 4-day ground track repeat interval. It will be interesting to see whether USA 186 will attain a 7-day ground track repeat interval similar to the current repeat interval of USA 161.

(Update added 15 september 2013: A further and well-illustrated update, documenting and constraining the constellation of orbital planes in past and present even further, can be read here).

(Note: I am indebted to Ted Molczan for comments on a draft of this post, and for providing me a spreadsheet to calculate the ground track repeat intervals. Any errors of fact or interpretation in this post are solely mine)

USA 161 new orbit finally established

The saga earlier covered here and here is finally coming to an end: it seems that the KH-12 keyhole USA 161 now no longer is escaping our detection.

The reboost on August 24 has provided our observer's and analysts corps with quite a challenge. After initial failures to recover it, the satellite was detected by several observers (including me) for a number of times in the early days of September. But in each case it was subsequently lost again and each new preliminary orbit solution put forward seemed to be wrong (see the two posts linked above in the introduction). Analysts were in despair, and observers confused.

Then Ted finally found a solution which seemed to agree with all observations and asked observers to search according to this search orbit early this week. Following this, Scott Tilley in the USA indeed recovered the object in a position much as predicted by Ted's solution, with Russell Eberst in Scotland following suit.

The now established orbit is quite different from the earlier search orbits. Instead of the perigee having  been raised, it turns out that it has been lowered, with the perigee 40 km lower and apogee 120 km lowered.

USA 161 playing hide-and-seek with observers

A few days ago, I wrote about the effort to recover the KH-12 Keyhole optical reconnaissance satellite USA 161 (01-044A). After it went "missing" following August 24, and not everybody bought into the opinion that it was de-orbitted, it was recovered in the first days of September by an effort of several observers, including Pierre Neirinck and me. It had made a massive orbital manoeuvre (for more details, read here).

Following Pierre Neirinck's and my positive observation on September 1-2 already reported earlier, Björn Gimmle in Norway as well as Pierre and I failed to see it on the night of September 2-3. This could (in the case of Pierre and me) however have been due to unfavourable observing conditions at both our localities in France and the Netherlands.

Next Russell Eberst in Scotland  observed it again on September 3-4. However, on subsequent orbits it definitely got lost again. Scott Tilley in the US could not find it on September 5 and neither could Pierre Neirinck in France (I had meanwhile dropped out of the chase due to bad weather).

Next, Scott Tilley positively observed it on September 6th in an orbital position definitely out of sync with Pierre and my observations from September 1-2. This indicated that USA 161 made yet another major manoeuvre around the time of Russell's September 3-4 observation.

The situation now had gotten very confusing, with one of the analysts trying to solve the discrepancies by suggesting that Russell's observation was not USA 161 but a random stray. This is unlikely though, as any object in LEO big enough to be mistaken for USA 161 is catalogued, and Russell's object did not match any of these known catalogued objects. Moreover, as another analyst remarked, the solution to exclude Russell's observation and link our September 2-3 observations with Scott's September 6 observation, would yield very unrealistic drag parameters.

It got even more confusing for a short while, when Italian observer Alberto Rango reported a possible observation on 6-7 September, but with hesitation as he wasn't too sure. In this case, it quickly turned out to be a stray, ironically the French optical reconnaissance satellite Spot 2.

So, for the moment we have lost USA 161 again. Our observer's corps is now trying to search according to a number of possible orbital solutions, most of them no more than educated guesses. I am confident that given time, it will be found again. Given that the weather has turned bad and that the advancing winter is quickly diminishing my midnight window for USA 161 (it can now only be seen low in the north, where I have horizon obstruction), I think I am out of the chase however.

USA 161: "The reports of my death are greatly exaggerated..."

KH-12 Keyhole USA 161 (01-044A) is alive! Pierre Neirinck and I observed it last night around 23:55 UTC (1 Sept). Below is one of the two images of it which I captured:

click image to enlarge

The Keyhole, launched from Vandenbergh on 5 October 2001, went AWOL on or short after 24 August, with several observers failing to observe it in a window well around its last orbital position after that date. This lead to some suggestions, covered earlier here, that it could have been de-orbitted. After all, a new Keyhole, USA 224 (11-002A) had been launched in the same orbital plane on January 20, 2011, ostensibly as a replacement for USA 161.

Not everybody took to the idea of a de-orbit for USA 161 though. It's much older sister ship in the evening plane, USA 129 (96-072A), was after all still active even though USA 186 (05-042A) had been placed in the same orbital plane in 2005. So why de-orbit the newer USA 161 but leave the much older (and presumably less modern) USA 129 up?

The alternative to a de-orbit, was a massive reboost into a different orbit. This option got more credibility when an anonymous radio observer reported the possible reception of a radiosignal from USA 161 on August 26. Based on this possible reception, Ted Molczan dispatched a number of search orbits to the active observers, and the hunt for Red October USA 161 was on...

Skies were overcast in Leiden at that time, but on 28-29 August it cleared somewhat (with the emphasis on "somewhat"). I tried to cover the nominal plane of the search orbits that night (which meant staying up late to 2 am local time) under conditions that can only be described as abominable (thin and sometimes thicker clouds) but failed to recover the satellite. That could easily have been due to the conditions though. In France, Pierre Neirinck suffered the same conditions.

On the night of 30-31 August, Pierre Neirinck in France spotted an object that could be USA 161 near 00:17 UTC. As his sky suffered from clouds, there was some uncertainty in the position he obtained. His observation suggested that the satellite was moving in an orbital plane that was shifted slightly more eastwards than the plane of the search orbits.

On the night of August 31-September 1, Björn Gimmle in Norway possibly observed it again near 23:20 UTC, but he wasn't too sure. Pierre Neirinck observing from France between 22:58-23:23 UTC did not see it. Neither did I, keeping (under good sky conditions) a visual and photographic watch between 23:31-23:46 UTC. Red October USA 161 turned out to be elusive and not willing to give up it's location easily!

Third time is a charm however (or, as we say in Dutch: Drie maal is Scheepsrecht, which is ambiguous to translate beacuse the exact meaning of "scheepsrecht" is under dispute: but it is something like "Three times is Ship's Justice" or "Three times is Alderman's Justice").

On the night of September 1-2, both Pierre in France and I in the Netherlands observed it unequivocally around 23:55 UTC. Keeping a visual and photographic watch under good conditions, I picked it up visually somewhat east of Polaris and under Cassiopeia, and just under the FOV of my camera. I quickly re-aimed and shot two images (one of them shown above), yielding four points. It was steady and at its brightest about mag. +2, a naked eye object. At the same time, Pierre in France also saw it visually and got three points.

With these data of last night, the new orbit is starting to get a bit of shape - probably enough for others to recover it more easily the coming nights. Probably not here at Leiden though: the sky has grown very hazy today (thin clouds) and I need some sleep.

The very preliminary orbit still needs more observations before it becomes accurate, but it looks like the perigee has been significantly raised to twice the altitude it was (from 303 km to ~590 km), and apogee slightly lowered (from 911 km to ~780 km).

These kind of situations, where a satellite makes a big manoeuvre and the hunt is on to recover it, are always exciting times where the hobby gets most fun!

KH-12 USA 161 de-orbited? [updated 02/09/2011]

UPDATE 2 Sept 2011: USA 161 is Still Alive! It has not been deorbitted but made a large manoeuvre. Read more about the recovery here.

Negative observations on Wednesday and Thursday 24-25 and 25-26 August reported by Russell Eberst from Scotland on SeeSat-L and Pierre Neirinck from France (priv. com) suggest that the KH-12 Keyhole USA 161 (2001-044A), an advanced high resolution optical reconnaisance satellite launched on 5 October 2001, has either undergone a large manoeuvre or (more likely) has been de-orbited last week.

Earlier this year (January 20, 2011), USA 224 (2011-002A) was launched as NROL-49 and put in the same orbital plane as USA 161, probably as a replacement for the latter.

Below are two archive pictures I shot of USA 161 brightly flaring twice on 30 July 2009:

click image to enlarge

The remaining KH-12 constellation (if indeed USA 161 has been de-orbitted last week) now consists of three satellites: USA 129 (96-072A), USA 186 (05-042A) and USA 224 (2011-002A), the oldest of which (USA 129) is now 15 years in service.

USA 224 which replaced USA 161 represents the noon and midnight plane. USA 129 and USA 186 represent the morning and evening plane. Below diagram shows the satellite constellation as it is now USA 161 has presumably been de-orbitted:

click diagram to enlarge

More flashing NanoSail-D, and flaring KH-12 USA 224

A week after my May 24 observations, I observed NanoSail-D (2010-062L) again, the experimental NASA solar sail.

NanoSail-D (image: NASA/MSFC)

As a week ago, it became very bright after culmination, while descending in the south, and was rapidly flashing again. It was easily seen by the naked eye, reaching mag. +1 or possibly +0.5.

In fact it is so bright, that the pixel brightness of the trail reached saturation on two of the three images. The first image (below) did yield brightness information: the resulting curve is shown beneath it. The flash period is irregular, but periods of 0.5s and 1.0s pop up frequently in the diagram (for actual determined flash times, see here. Astrometry on the satellite itself can be found here).

click images to enlarge

As can be seen on the images, the satellite was in a race with an untimely field of clouds (the orangish streaks in the images), staying just ahead of it. Visually, the brightness fluctuation was much more apparent than it is on these images (due to the saturation of the latter): it was very clearly flashing.

Nanosail-D was not the only object flashing. USA 224 (11-002A), the new KH-12 Keyhole launched on January 20 this year, flared too, while passing through the zenith, with flares at 23:48:27.3 and 23:48:31.8 UTC (May 31). The "saddle" and elevated brightness between the two flares is interesting (the trail is notably fainter before the first flash, and subsequent images show it is fainter again after the second flash):

click images to enlarge

This was the second time I imaged USA 224 (The first time was May 24). In addition to USA 224 and NanoSail, I also imaged another KH-12 Keyhole, USA 161 (01-044A), and a Lacrosse SAR, Lacrosse 3 (97-064A).

Manoeuvring KeyHoles and the flashing Iridium 33 wreckage

July 2010 so far yielded a nice series of clear evenings, due to very warm, sunny weather (in most cases allowing observations in shorts and shirt). I observed on July 3, 4, 6, 12, 15, 16, 17 18, 19 and 22.

Two manoeuvring KeyHoles

Prime targets this month were the KH-12 KeyHoles USA 186 (05-042A) and USA 161 (01-044A). These both manoeuvred on the 14th of July, giving us observers a nice task of recovery and renewed tracking.

The manoeuvre of USA 186 (05-042A) was first noted by Pierre Neirinck in France. After some other observers missed it, he observed it being very late, but initially lost his reference points. Ted Molczan next created a number of search orbits, based on different presumed manoeuvre times. Next Alberto Rango and me again recovered the satellite (Alberto first while I still had daytime, then me on the next orbit, in deep twilight), in an orbit very close to one of Ted's search orbits.

Using pre-manoeuvre and post-manoevre orbits calculated by Ted Molczan from our observations, the manoeuvre occurred on July 14th at the ascending equator crossing at about 15:00 UTC, over Indonesia.

Next it turned out that another KH-12 Keyhole, USA 161 (01-044A) had also manoeuvred early on the 14th. Again, Pierre noted it first, observing it 12 minutes late on July 17th. Next Ted and a number of other observers joined the recovery (including me at some point). Using pre- and post-manoeuvre orbits calculated by Ted and Mike from our observations, the manoeuvre ocurred at the ascending equator crossing near 00:20 UTC, July 14th, near Hawaii.


The flashing behaviour of the Iridium 33 wreckage

On 10 February 2009, the American Iridium 33 (97-051C) telephone communication satellite and a defunct Russian satellite, Kosmos 2251, collided in space. A large number of debris pieces were spread over Low Earth Orbit (see here), and the main wreckages of the two objects kept orbiting, now wildly out of control.

The Iridium 33 wreckage (97-051C) made some fine passes last month, displaying the same kind of flashing behaviour due to tumbling that I also observed shortly after the collision in 2009 (see here, here and here). Some of these flashes are easy naked eye flashes, reaching mag. +0. The object interchanges bright flashes like these with (more numerous) fainter flashes in the +4 range.

I targetted the satellite wreckage several times this month to determine the flashing behaviour. In March 2009, it showed a period of 4.7 seconds. Analayses of the imagery of the past few nights, shows this has changed to about 3.1 seconds. Below is one of several images, taken on July 16th, showing a series of fainter and brighter flares:

click image to enlarge

Below are graphic representations of the flare positions (yellow dots) observed on consecutive nights (resp 16-17, 17-18, 18-19 and 22-23 July 2010). Please note: only flares happening during photographic exposures are shown here. There were more flares, but these happened while the camera wasn't open:

click maps to enlarge

(maps made using Heavensat)

An unusual flare was captured on July 17-18, consisting of a triple flare with flares within 0.5 seconds:

click image to enlarge

Other objects besides the KH-12 Keyholes USA 161 and USA 186, and the Iridium 33 wreckage observed last 3 weeks include:

- the geostationary objects Milstar 5, Mentor 2 and Mentor 4 (USA 202);
- the HEO objects USA 184, the USA 40 rk;
- the LEO objects Progress-M 04M, MSX, Lacrosse 5, the Lacrosse 5r, IGS 1B, the IGS 5r, USA 32, the NOSS 3-3 duo and the USA 144 decoy,;
- plus a large number of GEO and LEO strays.

I have yet to analyse the USA 144 decoy (99-028C) data from July 20 for a new tumble period determination.

Progress-M 04M, MSX, and Mentor 2

A long spell of very warm, sunny weather is resulting in several clear nights. Since my last observations reported here (those of June 2nd), I have been able to observe on June 3, 13, 14, 16, 17, 22, 24, 26 and 29. Objects include Progress-M 04M, Mentor 2, Mentor 4 (USA 202), USA 161, USA 32, USA 184, MSX, Milstar 5, the NOSS 3-1 duo, and the STSS Demo-1. This does not include a number of non-classified strays also captured.

USA 161 (01-044A) slowly flared to -1 at 23:58:59 UTC (24 Jun).

Below are a few pictures. First: UARS captured as a stray, flaring, on June 16th:

click image to enlarge

Progress-M 04M on 26 and 29 June:

click images to enlarge

Geostationary USA 202 (Mentor 4), in the trees low in the sky (altitude about 17.5 degrees):

click image to enlarge

Mentor 2 (geostationary), MSX and a stray (HJ-1A, a Chinese Earth Observation Satellite)

click image to enlarge

Observations, a flare, and a logo

Over the past week I could observe on four evening: 11/12, 15/16, 16/17 and 17/18 August. Targets imaged on these nights were the three KH-12 Keyholes (USA 129, 161 and 186), the Japanese prematurely defunct SAR IGS 1B, and the US SAR Lacrosse 3.

USA 186 (05-042A) provided a nice mag. -2 flare on 16 Aug at 20:52:07.0 UTC. It was captured in an image, but unfortunately a too hasty camera pointing meant the satellite run out of the image before the end of the exposure. the flare is on it though, close to the image edge. Below is a crop of the relevant part of the image, and the derived brightness profile.

Note that the "saw-tooth" pattern in the profile is due to the satellite trail being at ~45 deg angle to the pixel orientation, i.e. it is an artifact of the pixel grid.

(click images to enlarge)

In a moment of boredom last weekend, I designed something long overdue for SatTrackCam Leiden (Cospar 4353): a logo.

It is a bit inspired by the "patches" the NRO employees create for their covert space missions (see here and here for a discussion and examples). Hence all symbols used have some meaning (have fun interpreting!). The Latin(ish) roughly translates to "All Your Nightly Secrets Are Belong To Us", a pun at the NRO's credo "We Own the Night" used in some of their patches and the infamous "All Your Base Are Belong To Us" of gaming/internet lore.

Flaring Keyhole USA 161

Yesterday evening/early night was a night with intermittent very clear skies, and large cumulus fields roving the skies. I was lucky though with the selected targets, although some narrowly escaped the roving cloud fields only. I observed 3 Keyholes (USA 129, USA 161 and USA 186) and Lacrosse 3.

USA 129 (96-072A) was imaged low in the sky in a small gap between clouds. USA 186 (05-042A) was imaged in twilight and the trails were rather faint. It briefly flared to mag. -1, before the camera was open, at roughly 22:59:50 UTC.

USA 161 ((01-044A, a Keyhole high-resolution optical reconnaissance satellite, like the other two USA objects mentioned) also briefly flared to -1 a few times. It did so twice while the camera was open, at 23:28:13.40 UTC and 23:30:17.15 UTC, resulting in the pictures below:

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The second image yielded this brightness profile, with the flare saturating at the peak:

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Keyhole USA 161

Yesterday evening started cloudy, with rain showers. As a result, I missed the splendid NLC display as seen from Belgium and the southern and eastern Netherlands.

After midnight it cleared, and this allowed me to capture the Keyhole satellite USA 161 (01-044A) again. It was nicely on time. A bright mag. 0 stray, which turned out to be the Russian r/b 84-072B, made a similar trajectory 3 minutes earlier.

Below image shows the Keyhole (01-044A) crossing the Milky Way in central Cygnus (I pushed the levels and contrasts of this image a bit in Photoshop to bring out the Milky Way better).

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Clear nights, and the NOSS 3-4 rocket brightness behaviour

A series of clear nights the past week, allowing a series of observations of the STSS-ATRR rocket (09-023B) and two Keyholes, USA 186 (05-042A) and USA 161 (01-044A). 09-023B keeps being an interesting target, as its orbital evolution is that quick that it necessitates continuous coverage. The current orbit projects decay around mid-August.

About a week ago, on May 19-20th (see here), I obtained images on the NOSS 3-4 r (07-027B). This spent Centaur rocket of the NOSS 3-4 launch shows a slow brightness cycle. I obtained some partial brightness profiles from the trail photographs, including an interesting one covering one of the brightness peaks:

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It can be clearly sees that this (10.05 s) part of the cycle consists of two components, a slow modestly exponential brightness development with a short narrow peak superimposed on it.

The Misty 2 decoy, USA 129, IGS 1B and more

Yesterday evening was a very clear evening. A bright moon lit the sky though.

Several objects were imaged. Two Keyhole satellites were captured: USA 129 (96-072A) and USA 161 (01-044A). For the first time this year, the Japanese IGS 1B (03-009B) defunct radar satellite was in range again, always a sure sign spring has arrived. Below are two images, of USA 129 and IGS 1B.

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Among the HEO objects, the SIGINT USA 200 (08-010A) and the USA 144 deb/Misty 2 decoy (99-028C) were captured.

The latter is an interesting object. Launched in May 1999, a bright object from the launch was tracked by amateur observers (see story here). After some time it became clear from the orbital behaviour of the object, that it could not be a real operational payload. Rather, it is a piece of debris or a decoy meant to draw attention away from the real stealth payload. The object is bright, but probably small and very lightweight, and moving in a 2700 x 3100 km orbit. Below is the image I obtained on a pass of this object last evening.

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Keyhole USA 161 flaring

On the night of April 1-2, the Keyhole optical satellite USA 161 (01-044A) flared brightly to mag. -2 just after shadow exit. I shot a whole series of images (yielding 7 positions), of which this is the first (exposure starting a few seconds after flare maximum):

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The same evening I also captured the Keyhole USA 129 (96-072A). HEO objects imaged were the SIGINT USA 200 (08-010A) and two brief glints by NOSS 2-3A (96-029A). The Russian Kosmos 2392 (02-037A) was captured as a stray on the USA 200 images.

Lacrosses and a very fine USA 161 flare

Coming back from a date shortly after midnight of August 23-24, I noted it was very clear, with only occasional small cloud fields passing. This allowed me to photographically target the optical imaging Keyhole satellite USA 161 (01-044A) and the radar Lacrosses 4 & 5 (00-047A & 05-016A).

USA 161 briefly brightened in Cassiopia, featuring a very short mag. 0 flare at 23:44:09 UTC. I was so lucky to have the camera open at that time, resulting in this very fine flare picture (with below it, the brightness profile):

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IGS-es, USA 193, and other stuff during beautiful clear nights

SatTrackCam Leiden just experienced a few beautifully clear, dark & transparent nights. The result is a fine batch of positions on several objects, including Keyholes (USA 161), Lacrosses (3, 4 & 5), USA 193 and the old & new Japanese IGS-es. The latter include my first positions on IGS 4A/R2 (07-005A).

The first capture of the latter object was when I was waiting for its rocket launcher (IGS 4r/R2r, 07-005C) on the night of May 17-18. Suddenly a bright (+2) object appeared 2 minutes before 07-005C should, following a similar trajectory. I made a photograph and then found out it was the A component.

Due to a goof from my side I initially thought it was the optical satellite (due to it having the "A" designation, analogue to IGS 1A, 03-009A) and hence was surprised to find it was so bright. Only later I realized it is the (intrinsically brighter) radar sat.

Keyhole USA 161 (01-044A) was observed flaring on the 18th at 00:12:50 UTC (-1.5, slow) and 00:14:13 UTC (-1, short).

USA 193 (06-057A) was bright.

Lacrosse 5 (05-016A) was elusive. On the 18th, it initially was +2 low in the sky but then quickly faded beyond vision for much of the pass.

Below are trail images of the "new" IGS 4A/R2, it's rocket 4R/R2r cruising through Lyra, Lacrosse 3 cruising amongst the Coma cluster stars, and an Iridium flare in twilight.

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Composite image of a USA 161 pass

Below image is a composite of two 10.7 second images, 35 seconds apart, made during yesterday's USA 161 (01-044A) pass. It includes the flare image posted earlier.

The stitch of the two images was made with Hugin/PTStitcher, the same software I use for my daylight panorama images.

The flare effect is even more accentuated in this composite, and the wide angle (roughly 50 x 50 degrees) makes several constellations well recognizable.

The glare in the lower right corner is reflection from a lamp on the courtyard.

(this image is of course reduced in size and compressed compared to the original, hence the fainter stars are lost).

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USA 161 flare, beautiful evening

Yesterday evening was very clear, thanks to a strong wind blowing the clouds away. I could observe until 3 am, when clouds came in again.

Highlight of the session was Keyhole satellite USA 161 (01-044A). It was very bright for much of its pass (about +2) and then flared to mag. -1.5 at 00:00:46 UTC. It was so nice to do that while the camera was open: image is below.

Other catches included Lacrosses 3 & 4 (97-064A & 00-047A) and IGS 1B (03-009B). One of the Lacrosse 3 images also captured a stray, which turned out to be the Kosmos 2292 SL-8 rocket (94-061B). Several other bright strays were seen, three of them flaring nicely, while preparing the camera.

I had USA 161 some 0.6s late, IGS 1B some 2.6s late, Lacrosse 4 some 0.4s late, and Lacrosse 3 some 0.3s early.

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