USA 224 has manoeuvered

During the night of June 12-13, I was doing a periodic checkup on the KH-11 Advanced Enhanced CRYSTAL satellites  USA 224 (2011-002A) and USA 314 (2021-032A) that occupy the KH-11 primary East plane. This because I expect USA 224 to manoeuvre to the secondary East plane at some point this summer, now USA 314 has recently been launched into its orbital plane as a replacement (see discussion in my earlier blogpost here).

USA 224 did not appear at the nominal time on June 13 but some 2m 20s late, indicating a manoeuvre.

Observations by David Brierley and me on June 12/13 and 13/14 have established this preliminary post-manoeuvre orbit:

USA 224                                                  255 x 998 km
1 37348U 11002A   21165.00715133 0.00014912  00000-0  12302-3 0    05
2 37348  97.8892 276.6083 0530502 157.6427 204.8870 14.81006602    06

It is clear that this is not the big plane-changing manoeuver expected, but a small regular orbit upkeeping manoeuvre: apogee was raised by some 10 km. 

From the pre- and post-manoeuvre orbit,  I calculate that the manoeuvre took place on Thursday June 10 near 14:14 UT, over the Atlantic, during crossing through the descending node and perigee. 

As usual, the manoeuvre happened while perigee was situated over the equator (when the Mean Anomaly is near 180 degrees, this is always a moment to watch out for manoeuvres). This allows to make adjustments in both orbital altitude and inclination in the same burn, with a minimum expense of fuel.

USA 314 (NROL-82) imaged

 

click to enlarge

Last Monday 26 April at 20:47:00 UT, ULA launched a classified payload for the NRO under the launch designation NROL-82. The payload is now designated USA 314. I wrote about the launch and that it is almost certainly an ADVANCED ENHANCED CRYSTAL KH-11 electro-optical reconnaissance satellite in an earlier post.

The payload was picked up on the first orbit by radio observer Scott Tilley in Canada, and next, guided by the radio observations, Cees Bassa (who is just like me in the Netherlands) optically imaged it on the second and third orbit.

Thanks to information from the radio observations, #NROL82 was caught in video observations on its second pass. It passed close to Polaris in the top left of this image at 23:45:30UTC. pic.twitter.com/HB8bSFy84e

— Cees Bassa (@cgbassa) April 27, 2021

 

I tried to image it from Leiden on the second orbit as well, but as it turns out it passed outside my camera field during that pass.

The next night, and with a more firm search orbit based on the data from the previous night available, I did succesfully image it. The photograph in top of this post was made with a Canon EOS 80D camera and Samyang 1.4/85 mm lens (at F2.0, 1600 ISO, 1 second exposure). 

I also obtained video, using the WATEC 902H2 Supreme with a 1.8/50 mm lens:

The payload is designated USA 314 (catalogue nr 48247, COSPAR 2021-032A) and as usual CSpOC does not publish orbital data. But our observations show that it is in a 528 x 755 km, 98.1 degree inclined sun-synchonous orbit.

The orbital plane is even closer to that of USA 224 than anticipated: a difference of only 1.1 degree in RAAN and 0.2 degrees in orbital inclination. The orbital altitude is somewhat different and the orbital eccentricity is less than our initial guess. Perhaps it will manoeuvre over the coming days/weeks to the same altitudes as USA 224, perhaps it will not: we will see!

So in all, the NROL-82 payload's orbit is pretty much what was expected, apart from a slightly different initial orbital altitude.

USA 224 and the new payload USA 314 currently move almost in phase, and as a result they are relatively close, with continuous sight of each other. It is well possible that USA 224 is imaging the new payload as a post-launch health checkup.

The image below shows the coplanar character of the USA 224 and USA 314 orbits, and the spatial proximity in viewing distance of each other:

click to enlarge

As I pointed out in a previous post, based on historical patterns I expect that, after a checkout-phase that may take a couple of weeks, the new USA 314 will take over from USA 224 in the KH-11 primary East orbital plane. USA 224 will then likely be manoeuvered into a lower orbit (~400 km) and its orbital plane will be moved to the 'secondary' East plane, some 10-20 degrees east in RAAN of the current orbital plane.