Friday, 18 May 2012

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):

click image to enlarge

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:

click image to enlarge

 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.

No comments: