Wednesday 29 April 2015

KH-11 USA 224 recovered

Over the past week I twice tried to recover the KH-11 CRYSTAL ('Keyhole') USA 224 (2011-002A) but failed. Leo Barhorst and Cees Bassa however did recover it on the night of April 27-28, in an orbital plane which is 4 degrees more westward than its previous plane. This meant that on two previous nights when I was doing a 1.5-hours (one orbital revolution) photographic coverage of the old plane, it actually passed outside the FOV of my camera...

Last night, based on Cees' search orbit, I did observe it as it was passing through Lyra around 22:57 UT. The image above and below shows it, together with the old Japanese scientific satellite Tansei 3 (MS-T3, 1977-012A), which was captured as a stray in the same images. The Japanese satellite is moving in a much higher orbit, as can be seen from the much shorter trails. It slowly faded in and out, so it appears to be slowly tumbling.

The image below is a stack of 13 images (4 seconds exposure each, with 5-second gaps). The image above at the top of this post is a single image from this series. The images were made with the very fine Samyang 1.4/85 mm lens.

The plane change was probably done to keep the separation of this primary East plane KH with the primary West plane KH (USA 245) near 48-49 degrees (the angle between the primary East and West planes maintained over the past several years). This would also bring the separation with USA 161, the secondary East plane KH, to 25 degrees, similar to the current distance between the orbital planes of  USA 245 and USA 186 in the primary and secondary West plane.

I therefore expect that when we recover USA 161, the secondary East plane KH, it will be in an orbital plane about 25 degrees east of USA 224.

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