Tuesday, 19 April 2011

NROL-34 recovered!

NROL-34 code-named ODIN is a classified payload launched by the NRO on 15 April 2011 (last Friday), 04:24:10 UTC. The launch itself was called FRIGGA, see the launch and mission patches here.

Initially suspected to be a Trumpet destined for a Molniya orbit by independant analysts, a change of mind was promoted short before the launch by new information that suggested it to be a new NOSS pair. NOSS stands for Naval Ocean Surveillance System, and the newer NOSS typically consist of two satellites forming a close tandem.

After the launch of NROL-34 on April 15, the hunt was on to recover it: and hence for me it was very frustrating to see that a period of cloudy skies ensued at Cospar 4353!

Initial attempts by several observers to locate it according to orbit estimates published by Ted failed (see here and here). Then Mike reported an observation of what could be the NOSS duo from Texas on April 17, prompting a new orbit estimate. However, several other observers plus Mike himself next failed to recover it according to this orbit estimate (see here, here, here and here). So, the situation was very unclear: where was NROL-34, and what did Mike see?

Independant of each other, BWGS president Bram Dorreman in Belgium and me in Leiden, the Netherlands, turned back to Ted's initial orbit estimate, for a prolonged orbit plane search, yesterday evening: Bram visually, and I used the camera. This was the first clear evening allowing this. Conditions were poor, as the only potentially visible pass was very low in the west (20 degrees altitude), with a very poor phase angle and hence expected low brightness. I therefore decided to use the EF 2.8/100 mm Macro lens, as this picks up fainter objects - the trade-off is however a smaller FOV. I started the photographic survey at 20:05:20 UTC, making a continuous series of 10s exposures separated by 10 seconds each, and ended at 20:13:00 UTC.

On the 4th exposure (20:06:22.30 - 20:06:32.35 UTC), a very faint trail showed up. The trail is extremely marginal in quality, barely visible above the background noise: but it turned out to be one of the two NOSS objects (the leading one, probably) of the elusive NROL-34!

Below is (a part of) the image, with the very faint, barely visible trail marked by arrows at the start and end (you might have to adjust your monitor settings to see it, and definitely need to click the image below to full size):

click image to enlarge

After measuring the image, and finding no match to a known object, I privately mailed to Ted and Mike (and inadvertently switched the trail ends in that proces, initially reporting the trail end as the first position and the trail start as the second, instead of the correct other way around: a revised, correct report can be found here). The object passed about 4 minutes earlier than the nominal predicted pass time from Ted's initial NROL-34 elset estimate.

Meanwhile, it turned out, Bram in Belgium had visually (binoculars) picked up the same object, as well as a second object trailing it by 16 seconds. The latter probably was too faint to be photographed, as it was not visible on my images.

Based on a quick revised search orbit from Bram and my observations, Ted next picked it up a few hours later from Toronto in Canada, and Kevin Fetter observed it from the USA as well, as did Tim Luton.

So, three days after launch NROL-34 finally has been recovered. The game can now begin to further refine the orbit, and monitor any subsequent manoeuvres. The new NOSS has been given the provisional designation NOSS 3-5 by our group of amateur observers.

Later that evening, I observed IGS 1B (03-009B: see my post on the expected re-entry of this object a year from now here) and the KH-12 USA 186 (05-042A), as well as (as strays) a duo of Globalstars, Globalstar 4 (98-008D) and Globalstar 37 (99-012D), trying to impersonate a NOSS (as if the evening wasn't already confusing enough!).

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