[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!

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.

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)

The orbit of USA 245 and the current KH-11 constellation

In the past two weeks (e.g. here, here and here) I have written about tracking USA 245 (2013-043A), the new KH-11 Keyhole (Evolved Enhanced CRYSTAL) optical reconnaissance satellite launched as NROL-65 on August 28.

USA 245 has been launched in the same orbital plane as USA 186 (2005-042A), a KH-11 Keyhole launched on 19 October 2005. In time, it is therefore probably intended to replace this satellite.

click image to enlarge

The diagram above (made with JSatTrak and using our amateur derived orbits for the two satellites) shows the orbital similarity between USA 186 and USA 245. The orbital plane is the same and the orbital altitudes are similar (and will probably be even more similar in the future, after more USA 245 orbital manoeuvering). USA 245 (white) is currently in a 262 x 1010 km, 97.87 degree inclined orbit. USA 186 (green) is in a 263 x 1017, 97.93 degree inclined orbit.

The constellation of on-orbit KH-11 Keyholes now counts five satellites:

USA 129  (1996-072A)
USA 161  (2001-044A)
USA 186  (2005-042A)
USA 224  (2011-002A)
USA 245  (2013-043A)

These operate in two rather loose orbital planes. One, sometimes called the "West plane", produces passes in the local evening and morning, around 10 am and 9 pm local time. To this plane belong USA 129, USA 186 and the new USA 245. The other plane, sometimes called the "East plane", produces passes one to two hours after local noon and local midnight, around 1 am and 2 pm local time. This plane is occupied by USA 224 and USA 161.

The orbits of all the Keyholes currently in orbit are pictured below, with the two orbital planes well visible left and right of the center meridian:

click image to enlarge

Of the Keyholes still in orbit and presumably operational (as they are periodically reboosted to maintain their operational configuration), USA 129, launched on 20 December 1996, has been on orbit for almost 17 years now. As can be seen in this table of data compiled by Ted Molczan, this is the longest operational lifetime of any of the KH-11 Keyholes so far. It will be interesting to see how long they will keep it flying: it's last predecessor, USA 116 (1995-066A), was de-orbitted on 19 October 2008.

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.

(note added 14 Sep 2013: this post has a long follow-up post here, detailing past configurations of the KH-11/CRYSTAL constellation, and how I expect to see the satellite configuration re-arranged early 2014, when USA 245 becomes fully operational)

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.

click image to enlarge

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.

click image to enlarge

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:

click image to enlarge

Tracking USA 245 (NROL-65)

In my previous post I blogged about observations of NROL-65, the new KH-11 Keyhole optical reconnaissance satellite launched on 28 August. As a satellite, it now has the designation USA 245 (NROL-65 was the launch number, i.e. NRO Launch 65).

I already blogged about how our small bunch of dedicated amateur trackers located and followed this classified satellite within hours after launch (I myself observed it on it's second revolution, 3 hours after launch). Since then, we have kept following it, documenting a number of orbital manoeuvres.

On the evening of August 30 Russell Eberst in Scotland and Cees Bassa in the Netherlands noted the satellite was notably late on the predictions, suggesting a manoeuvre. Observations by several observers (communicated on the SeeSat list) analyzed by Ted Molczan in Canada show it  manoeuvred on August 30 near 9:15 UTC from a 252 x 996 km into a 254 x 1002 km orbit.

A day later, on August 31 near 18:30 UTC, it manoeuvered again, to an approximately 259 x 1007 km orbit. It will probably manoeuvre more in the following days.

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I observed USA 245 yesterday evening, under challenging conditions: an untimely field of very thin clouds passed just as USA 245 was passing over Leiden, at an elevation of about 40 degrees in the west. The image above shows the trail between thin clouds (star field is in Hercules).

The satellite now has the Cospar code 2013-043A, and by looking at the omissions in the SSC catalogue numbering we know it has SSC ('NORAD') number 39232.

USA 245 (NROL-65), the new KH-11 Keyhole, seen 3 hours after launch

On 28 August 2013 at 18:03 UTC, a Delta IV-H with a classified NRO payload lifted off from Vandenberg AFB as NRO Launch 65 (NROL-65). It is widely believed that the payload is a KH-11/KH-12 Keyhole optical reconnaissance satellite.

1.5 hours after launch at the completion of its first orbit,  the upper stage and the payload were seen by Cees Bassa from the Netherlands, Björn Gimle in Sweden, Alexander Repnoy in the Ukraine and Jon Mikel in Spain .

The sky was still too bright in the western Netherlands during this pass. But on a second pass, three hours (two orbital revolutions) after launch, I captured the payload on photo and video when it made a fine near-Zenith pass over Leiden. It was faint, near mag. +4.5. Conditions were fair but not perfect: the sky was slightly hazy.

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The image above shows it traversing Lyra - the bright star is Vega. The image was shot with the F2.5/50mm Macro lens.

In the video below (with which YouTube unfortunately did not do a particularly good job, the original video is much better quality) shows it rising over the roof and passing near Altair, then shows a clip of it traversing Lyra. It was shot with the WATEC 902H and a 1.4/25mm lens.




Russell Eberst in Scotland and Cees Bassa in the Netherlands captured it during the same pass as well. Since then, the payload (the upper stage has been deorbited after the first revolution) was also seen by Ted Molczan in Toronto, Canada and filmed by Kevin Fetter in Canada.

Over the next few days, we will watch it finalizing its intended orbit. The orbital plane is the same as that of USA 186 (2005-042A), an earlier KH-11 launched in 2005.

Both the photography and video yielded a set of positional data that along with observations by other observers helped Ted Molczan to define a preliminary orbit.