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.

First post winter-blackout observations of KH-11 Keyhole/CRYSTAL USA 129

One by one the KH-11 Keyhole/CRYSTAL optical reconnaissance satellites are emerging from the Northern hemisphere winter black-out. Following USA 186 (2005-042A) on Feb 21, and USA 245 (2013-043A) on March 3, USA 129 (1996-072A) has now been recovered as well on March 21.

USA 129 was last seen by Greg Roberts in South Africa on Feb 12.  It had hence not been seen for over a month until it was recovered by me and Leo Barhorst last Friday evening. Below is my recovery image:

recovery image of USA 129, 21 March 2014

click image to enlarge

This means all three objects in the West (evening) plane have now been recovered. Recovery of the two East (midnight) plane objects (USA 161 and USA 224) will have to wait until mid-April.

I went to my secondary site in the Cronesteyn polder in the evening of March 21, with the explicit aim of recovering USA 129. I had aimed the camera, with the 1.4/85mm lens, at 33 degrees elevation, at a point covering the orbital plane of the satellite where it should just have emerged out of earth shadow.

And it did, 104 seconds late and 0.8 degree off-track from the orbital elements based on Greg's last observation of Feb 12. Running a series of images for several minutes, I snapped it on two images.

In Almere (also in the Netherlands), some 55 km Northeast of me, Leo Barhorst also captured it using his WATEC camera, and reported it as an "unknown".

Over the coming days, we hope to capture more positions as the satellite gradually becomes more visible.

click image to enlarge

That same evening, I photographed two other classified objects: USA 186 (2005-042A, above, with two strays Russian rocket boosters in the image as well) and SAR-Lupe 5 (2008-036A), a German military Synthetic Aperture Radar satellite.

click image to enlarge

SAR-Lupe 5 was captured by accident, when I was making a test image to check lens focus. Two satellites showed up in the test image: the very old Russian weather satellite Meteor 1-5 (1970-047A) and SAR-Lupe 5. As I had not carefully timed this image (I did not expect a classified object to be in it), Meteor 1-5 provided a welcome time calibration for the image. SAR-Lupe 5 was 57 seconds early and 1 degree off-track relative to 10-day old orbital elements.

Imaging USA 186 after the winter blackout

In yesterday's post I mentioned that while the southern hemisphere window on the evening Keyhole/Crystal satellites ended early February, for us in the northern hemisphere it is just starting. After Greg in South Africa did the last southern hemisphere observations of USA 186 (2005-042A) on Feb 12, Cees in the Netherlands did the first northern hemisphere observations on Feb 21.

Yesterday evening (Feb 26) I did my own first post winter-blackout observations of USA 186. I captured it on several images, including the one below which shows the satellite shortly after merging from eclipse on 30 degrees altitude in the N-NW:

click image to enlarge

As current passes at 52 N are still restricted to visibility very low in the northern sky, I could not target the satellite from my regular town center location (which has obstruction by buildings in the north). I therefore did a short bicycle trip to a spot 2 km southeast from my home, in the Cronesteyn polder on the eastern outskirts of Leiden. Visibility is horizon to horizon there.

As I expected the satellite to be faint this low in the N-NW sky, I used the 1.4/85 mm lens instead of the 2.5/50 mm lens I normally use on the KH-11 satellites. The satellite registered well on the images, and was some 10.3 seconds early on a 5-day-old elset. It is evidently still drifting in RAAN (see previous post). As visibility improves over the coming weeks, it will be interesting to follow it.

I also targetted some parts of the geostationary belt, but have not come yet to measuring those images (probably this weekend).

If weather cooperates the coming week, I will return to this observing spot to try to recover the new primary West plane KH USA 245 (2013-043A), which hasn't been seen since Greg's observations of January 11, i.e. for almost two months. USA 129 is not visible from 52 N yet.

USA 186 is defying the schedule

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

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

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

And nothing happened. USA 186 did not manoeuvre.

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

click images to enlarge

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

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

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

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

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

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

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

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

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

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

(click image to enlarge)

USA 129 on 28 September 2013
RIP ?

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

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

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

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

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

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

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

click image to enlarge

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

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

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

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

click image to enlarge

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

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

click image to enlarge

click image to enlarge

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

West plane KeyHole/CRYSTAL satellites:

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

(imaged 28 Sep 2013)

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

(imaged  5 October 2013)

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

(imaged 5 October 2013)

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

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

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

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

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

(click diagrams to enlarge)

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


New plane, lower apogee altitudes, and more circular orbit

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

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

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

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


A repeat of an earlier case

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

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

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

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

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

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

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

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


What to expect?

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

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

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

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

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

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

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

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


Why the apogee and perigee changes?

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


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

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.

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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)

More tracking of USA 245, and being flashed by ALOS

After my observations in the hours after launch on August the 28th and my observations on September 3, I observed the newly launched KH-11 Keyhole USA 245 (NROL-65, 2013-043A) again yesterday evening.

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It was brighter yesterday than during my previous observations, this time reaching an easy naked-eye brightness. Near 20:38:15 UTC it slowly brightened to mag.+1. Above is one of my images, showing it as it traverses the northern part of Cygnus.

Ten minutes earlier, I observed USA 186 (2005-042A), the KH-11 Keyhole launched in 2005 that USA 245 in time is meant to replace. For the moment, they probably will operate together in the same orbital plane for several years. The image below shows it traversing Cepheus.

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After observing USA 186 and while waiting for USA 245, a very bright (up to mag. 0), slowly and irregularly flaring object appeared near 20:33 UT. It turned out to be ALOS (2006-002A), the Japanese Earth Observation satellite that malfunctioned in 2011. It evidently is slowly tumbling. Below are two images, showing the irregular brightness variation:

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PAN is on the move, and detection of an unknown object in near-GEO

Last Wednesday evening (16 May) saw very clear skies. Combined with the absence of moonlight, an ideal situation to target geostationary objects, which are low in the sky for me at 52 N. As they are low  and I am in an urban environment, I need a very transparent sky.

Normally I use the 2.8/180mm Zeiss Sonnar, but this time I went for the SamYang 1.4/85mm. The limiting magnitude of this fine lens is only slightly less than that of the 180mm, but the FOV is twice as large (10 x 14 degrees). It is a geostationary magnet: in one single image I counted 20 geostationary or near-geostationary objects! In total, the session (a sweep of some 25 degrees of equatorial sky in the S-SE, at elevations of 15 to 25 degrees) recorded 38 objects: 7 classifieds, 30 unclassifieds and one unknown.


An UNKNOWN object on May 16

As part of the session, an object in near-Geostationary space was serendipitously observed that cannot be matched to any known object (for recorded positions, see here). It was slowly moving near the commercial geosats Eutelsat 36A and Eutelsat 36B (00-028A and 09-065A) and was captured on several images, small parts of four of which are shown below (note the movement relative to the stable Eutelsats):

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As Heavensat with the latest orbital catalogues loaded showed nothing in this position I initially logged it as a 'UNID'. Then a check with Ted's IDSat software resulted in a very superficial match with the DSP F20 cover (00-024E), but a clearly non-linear delta T suggested this could be a spurious match (see the questionmark and note under my data report here).  Next Mike McCants contacted me, it was indeed a spurious match in his opinion as his analysis of my data suggested an approximate orbit that does not match the DSP F20 cover at all. So for now, the object is designated as UNKNOWN 120516.

Objects like this do not spontaneously materialize, and there is no recent launch that can account for this object. It is therefore likely an old object being relocated. According to Mike, one possible (but by far not certain) option is that it is the classified object Mercury 1 (94-054A, or USA 105), which has not been observed for some time, being retired and relocated to a graveyard orbit.

Unfortunately, both Greg Roberts in South Africa and me here in the Netherlands were clouded out last night and today, so follow-up using Mike's approximate search orbits is troublesome for the moment.


PAN being relocated again

Another classified geostationary object on the move again is the enigmatic PAN (09-047A). This object has an unusual history of frequent relocations, moving to and fro in longitude each few months. It was at 44.9 E in the spring of 2011, then relocated to 39.1 E in the summer of 2011 and next moved to 52.5 E somewhere between late October 2011 (I still observed it at 39.1E on 23 October 2011) and January 2012, when Greg Roberts noted it missing after which Ian Roberts recovered it at 52.5 E early February.

And now its is moving again: Greg Roberts was the first to note this on May 10 and recovered it on May 14 and May 16 while it was and is moving towards 39.1 E (a position it has previously occupied). I imaged it near 39.1 E too on Wednesday evening May 16. Below is a part of one of the images, showing PAN and several commercial geostationary objects, as well as two old rocket boosters in GTO:

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 Other classified (near-)  geostationary objects observed this evening were the SIGINT Vortex 6 (89-035A, also in the process of being relocated), the SIGINT Mentor 4 (09-001A), it's rocket (09-001B), the Milstar 5 communication satellite (02-001A), the DSCS 3-13 R2 rocket (03-008C) and the DSP early-warning satellite DSP F23 (07-054A).

Apart from these geostationary objects, I observed the LEO object USA 186 (05-042A, a KH-12 Keyhole) as well that evening, in its new orbit after it manoeuvered earlier this year.

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:

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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:

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KH-12 USA 129 flaring: and IGS 1B again

A period of sunny weather commenced the past week, albeit with a trend towards increasing hazyness. I observed on the 19th, 20th and 21st of April, targets being the evening KH-12's USA 129 (96-072A) and USA 186 (05-042A), as well as IGS 1B (03-009B). An attempt to locate the geostationary satellite Mentor 2 (98-029A) on the 20th failed, probably because of the poor observing conditions.

Yesterday evening (21st April) the sky was quite hazy with, during twilight, abundant whisps of thin clouds. USA 129 (96-072A) slowly flared to mag. 0 at about 19:56:15 UTC, and the resulting picture of the flare amidst thin clouds in a still bluish twilight sky, looks very eerie:

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Some what later, I made this shot of IGS 1B (03-009B) gracefully sailing through Bootes:

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My story about the re-entry of the above pictured malfunctioned IGS 1B satellite in about a year from now, has been picked up, notably after Jim Oberg reposted it on the NASA Spaceflight Forum here. Two journalists contacted me with questions, and my post itself attracted some US Government attention (when the Executive Office of the President visits your weblog, you know it is being taken serious). So I guess some people have woken up now, and hopefully we will soon see a serious risk assessment and more pertinent information by the Japanese as to the tank content of the satellite.

NROL-34 recovered!

NROL-34 code-named ODIN is a classified payload launched by the NRO on 15 April 2011 (last Friday), 04:24:10 UTC. The launch itself was called FRIGGA, see the launch and mission patches here.

Initially suspected to be a Trumpet destined for a Molniya orbit by independant analysts, a change of mind was promoted short before the launch by new information that suggested it to be a new NOSS pair. NOSS stands for Naval Ocean Surveillance System, and the newer NOSS typically consist of two satellites forming a close tandem.

After the launch of NROL-34 on April 15, the hunt was on to recover it: and hence for me it was very frustrating to see that a period of cloudy skies ensued at Cospar 4353!

Initial attempts by several observers to locate it according to orbit estimates published by Ted failed (see here and here). Then Mike reported an observation of what could be the NOSS duo from Texas on April 17, prompting a new orbit estimate. However, several other observers plus Mike himself next failed to recover it according to this orbit estimate (see here, here, here and here). So, the situation was very unclear: where was NROL-34, and what did Mike see?

Independant of each other, BWGS president Bram Dorreman in Belgium and me in Leiden, the Netherlands, turned back to Ted's initial orbit estimate, for a prolonged orbit plane search, yesterday evening: Bram visually, and I used the camera. This was the first clear evening allowing this. Conditions were poor, as the only potentially visible pass was very low in the west (20 degrees altitude), with a very poor phase angle and hence expected low brightness. I therefore decided to use the EF 2.8/100 mm Macro lens, as this picks up fainter objects - the trade-off is however a smaller FOV. I started the photographic survey at 20:05:20 UTC, making a continuous series of 10s exposures separated by 10 seconds each, and ended at 20:13:00 UTC.

On the 4th exposure (20:06:22.30 - 20:06:32.35 UTC), a very faint trail showed up. The trail is extremely marginal in quality, barely visible above the background noise: but it turned out to be one of the two NOSS objects (the leading one, probably) of the elusive NROL-34!

Below is (a part of) the image, with the very faint, barely visible trail marked by arrows at the start and end (you might have to adjust your monitor settings to see it, and definitely need to click the image below to full size):

click image to enlarge

After measuring the image, and finding no match to a known object, I privately mailed to Ted and Mike (and inadvertently switched the trail ends in that proces, initially reporting the trail end as the first position and the trail start as the second, instead of the correct other way around: a revised, correct report can be found here). The object passed about 4 minutes earlier than the nominal predicted pass time from Ted's initial NROL-34 elset estimate.

Meanwhile, it turned out, Bram in Belgium had visually (binoculars) picked up the same object, as well as a second object trailing it by 16 seconds. The latter probably was too faint to be photographed, as it was not visible on my images.

Based on a quick revised search orbit from Bram and my observations, Ted next picked it up a few hours later from Toronto in Canada, and Kevin Fetter observed it from the USA as well, as did Tim Luton.

So, three days after launch NROL-34 finally has been recovered. The game can now begin to further refine the orbit, and monitor any subsequent manoeuvres. The new NOSS has been given the provisional designation NOSS 3-5 by our group of amateur observers.

Later that evening, I observed IGS 1B (03-009B: see my post on the expected re-entry of this object a year from now here) and the KH-12 USA 186 (05-042A), as well as (as strays) a duo of Globalstars, Globalstar 4 (98-008D) and Globalstar 37 (99-012D), trying to impersonate a NOSS (as if the evening wasn't already confusing enough!).

Bright and fast KH-12 USA 129 zapping through perigee

Yesterday evening was clear, and I observed the KH-12 Keyholes USA 129 (96-072A) , USA 186 (05-042A) as well as the SAR satellite Lacrosse 3 (97-064A).

USA 129 was making a pass at 40 degree altitude in the east, at an altitude of only 303 km only minutes from passing through perigee. As a result, it was bright and very fast, zipping through the sky at notable speed: very cool to watch. It resulted in two long bright trails on the images. Two strays were captured as well: a very faint Russian rocket stage (84-067B) in one image, and a brighter Russian rocket stage (Kosmos 1484 r, 83-075B) in the second. The latter cruised up parallel to USA 129, being overtaken by it when both were passing through the tail of the Big Dipper. See the image below, where the longer brighter trail (the lower one of the two) is USA 129, the other the Russian rocket stage:

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KH-12 USA 186 passed through the same sky area 20 minutes later, but at a much different altitude (830 km, against only 303 km for USA 129). The clear difference in trail length this generates, is shown by the image below, which is a stack of the two images of 19:41 and 20:03 UTC:

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Flaring Keyholes in a moonlit sky, and a BWGS meeting

The "Supermoon" of yesterday was not my only observational target. The sky was very transparent, and hence even with this full "supermoon" low in the southeast, conditions were fine for satellite observations.

I imaged two Lacrosses and two KH-12 Keyholes: Lacrosse 3 (97-064A), Lacrosse 5 (05-016A), USA 129 (96-072A) and USA 186 (05-042A). In one of the images, Rubin 4/SL-8 (03-042B) was captured as a faint stray.

Both of the Keyholes and one of the Lacrosses (Lacrosse 3) flared: KH-12 USA 129 did so while the camera was open, yielding the picture below (note the Hyades at the bottom):

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Flare times:

USA 129: 20:29:08 UTC
USA 186: 20:14:40 UTC
Lacrosse 3: 19:52:40 UTC

Below images show Lacrosse 3 ascending and brightnening over the chimney (with Canis minor in the upper right corner: this was just before it flared), and Lacrosse 5 descending through the tail of the Big Dipper (the fuzzy arc is a reflection from a nearby lightsource):

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These observations were all done just after returning from a trip to Belgium, where we had a meeting of the BWGS (Belgian Working Group Satellites). It was a small but nice gathering (six attendants, including this author). Below some pictures showing me (left) and Leo Barhorst (right): and BWGS president Bram Dorreman (all pictures taken by Koen Geukens):

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On the agenda were amongst others the future of flash observations; the observations of flaring geostationary satellites earlier this month; while I did a very short photo-presentation on the recent PAN relocation story (see also here). Our host that day was Koen Geukens.