Orbital ATK's Cygnus AO-9 cargoship chasing the ISS

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The two images above show Orbital ATK's Cygnus AO-9 cargoshi  chasing the International Space Station (ISS), a few hours prior to berthing. The Cygnus OA-9 cargoship, launched on May 21 from Wallops Island, brings supplies (food, equipment etc.) to the Space Station.

I could observe three passes of the two objects during the night of May 23-24: in all three cases the two objects could be seenr at the same time in the sky, with the Cygnus (the fainter trail in the images above) somewhat behind ISS.

The images above are from the first pass (21:48 UT, 23:48 local time), a high pass,  and the third pass (01:00 UT, 03:00m local time), low over the southwest horizon. The Cygnus spacecraft was about 22 seconds behind the ISS on the third pass. The sky over Leiden was somewhat hazy.

The very short third trail near the ISS on the first image is Kosmos 2392.

As usual, the Cygnus spacecraft was quite faint (mag +4.5), so not an easy naked eye target. The brightness of these Cygnus spacecraft is strongly phase-angle dependent. The Dragon spacecraft of their competitor SpaceX are much brighter and easier to see.

The video footage below is from the third pass:

UNID galore! Locating Govsat-1

The evening of 13 February 2018 was very clear. I used the WATEC video camera to track objects in Low Earth Orbit in evening twilight, and later in the evening did a short session on Geostationary satellites.

Over the course of this I recorded as much as 3 initially unidentified objects ("UNID's"): objects that at the time of observation did not match with a known orbit in either the unclassified JSpOC orbit database or our amateur database of classified objects.

The first of these UNID's was the one in the footage above, which appeared while I was waiting for another satellite to pass. It didn't match anything known. The ~62-degree orbital inclination from a circular fit to the data suggested something NOSS-ey. Mike McCants later managed to identify it as probably NOSS 6 (C), (1984-012C), last observed 10 months ago.

The other two UNID's appeared in my photographic imagery from later that evening aimed at geostationary objects. The first one was a short Northwards moving trail pointing to an object in GTO that was alas only visible in two pictures. Here is one of these two images (the image also shows the classified Early Warning satellite SBIRS-GEO 2 (2013-011A), which was the target of the image):

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This turned out to be the same object as a UNID imaged by Cees Bassa that same evening, and correlated by him to the object we designate as "Unknown 091017" (2009-790A). This object was first seen in 2009 and more recently "lost" for a while, as it was last seen 566 days (1.5 years) ago. This object in a 25 degree inclined GTO orbit (image below) is probably a rocket stage from a classified launch.

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The third UNID was an object near Geostationary altitudes, close to the commercial GEO sat Astra 3B. It is the object indicated with a yellow arrow below:

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I initially somehow managed to miss this object when going through my imagery, but Cees Bassa had imaged it that same evening and urged me to look for it in my imagery, after which I found it too.

This object is most likely Govsat-1 (SES 16; 2018-013A), launched for a joint-venture of SES and the Luxemburg government by SpaceX two weeks earlier on 31 January 2018. It is "aimed exclusively at government and defence users" and its orbit is classified (although its operational slot at 21.5 E has been made public). The military of several NATO countries will use it for secure communications as part of military and humanitarian operations. The satellite was built by Orbital ATK.

The orbital slot assigned to it is at 21.5 E. On the evening of 13 February we detected it at 23.8 E, some 2 degrees to the East of this, so it probably is still slowly drifting westwards towards 21.5 E, where it will arrive somewhere in the coming few days.

The object had a noted brightness variability (in the image above it was at its brightest, while it was completely invisible in some of the other images), indicating it is spinning, probably spin-stabilization while in transfer to its orbital destination.

This object will be very interesting to follow in the feature, as it has a port that allows another still to be launched object to dock to it.

Cygnus OA-7 and Dragon CRS-11 chasing the ISS in a twilight sky

ISS and Cygnus OA-7. Click to enlarge

June 3, the launch date of SpaceX's Dragon CRS-11 cargo spacecraft to the International Space Station (ISS), was clouded out in Leiden, much to my frustration.

But yesterday evening was (sort of) clear, albeit with cirrus in the sky and a moon that was quite a nuisance. It allowed me to observe the ISS, the Dragon CRS-11, and Orbital ATK's Cygnus OA-7, which had de-coupled from the ISS a few hours earlier, making a low elevation pass (less than 35 degrees elevation) in the southern sky.

The image above shows the ISS (the bright object near the tree) and, as a faint trail, the Cygnus OA-7 (upper right corner, in the cirrus), descending towards the SE horizon.

Below is a better picture of Cygnus OA-7, shot 25 seconds later (ISS is already behind the tree here):

Cygnus OA-7. Click image to enlarge

Cygnus OA-7 passed ~25 seconds after the ISS. One minute later, ~1m 25s behind the ISS and on a slightly lower elevation track came another object: Dragon CRS-11:

Dragon CRS-11. Click image to enlarge

I did not expect the Dragon to be behind the ISS: I expected it somewhat in front of it. So initially I was miffed that I missed it (see below, this evening did not go quite well): to be surprised by it appearing behind the ISS!

This evening did initially not go well, but in a weird way eventually turned out fine.

A number of objects would pass in a short timespan of a few minutes: USA 276, the Dragon solar panel covers, Dragon, ISS, and somewhere nearby the ISS also Cygnus OA-7.

There were no post-ISS-release elements for the Cygnus yet, so its position would be a guess, although I reckoned it probably still was close to the ISS. Cygnus are usually faint (this time too) and only naked eye objects under favourable circumstances (usually, as this time, close to shadow ingress).

For Dragon, only a day old elements were available. These placed Dragon a few minutes in front of the ISS. As it no doubt would have manoeuvered during that day, I expected it to be closer to the ISS in reality, but that it was behind the ISS, that was a bit unanticipated.

The passes occurred in twilight (sun about 10 deg below the horizon). As obtaining new astrometric data on USA 276 (see story here for as to why) was important, I had set up the WATEC video camera to capture it, from the loft window (the only spot in my house where I can view that low south). That took  me longer than expected, as I initially had some trouble finding the target area in the video view (it was still deep twilight).

When I finally had found the target starfield through which USA 276 should pass, I discovered to my dismay that the pass was already imminent within minutes. As I could not visually observe through the same loft window, nor photograph, I had to be outside for that, at the city moat near my house which offers a view low south. So I grabbed my photo gear and ran outside. Arrived at the observing spot, I found that I already missed the opportunity to visually see and photograph USA 276 (luckily, the video camera in the loft window did film it). I also feared I had missed Dragon CRS-11, as I already could see the ISS approaching in the southwest. So I said a few strong words...

As ISS had passed the moon (which was a bloody nuisance, smack in the middle of the trajectory line) and was descending into the trees low in the south-southeast, I spotted a second, not too bright object chasing it (see first two images above). As I was photographing it and it descended into the trees, I re-aimed my camera hoping to catch it in a gap on the other (left) side of the tree.

Then I saw yet another object descend into the right side of the tree, and realised this was either Dragon or Cygnus. I initially thought, to my dismay, that it would be just outside my camera FOV. Luckily, back home later it turned out it still was in the FOV (I used a 35 mm lens).

The first, faint object on the same trajectory as the ISS some 25 seconds behind it I for this moment identify as Cygnus OA-7. The second, brighter one, on a trajectory just south of that of the ISS some 1m 25s behind it, I for the moment identify as the Dragon CRS-11.