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).

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)

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.

click image to enlarge

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.