Imaging some splendid passes of HTV-9 (Kounotori-9) and Cygnus NG-13

It are very busy times at the International Space Station. Spaceships come and go.

First, on May 11, the US cargoship Cygnus NG-13 was released from the ISS, three months after berthing to it. This cargoship had been launched on 15 February 2020 and berthed on 18 February. After its release from the ISS two weeks ago, it is currently free-flying to do experiments. It will perform a controlled reentry over the southern Pacific on 29 May.

On 20 May at 17:31 UT, the Japanese cargoship HTV-9 (Kounotori-9) was launched. It berthed to the ISS on 25 May. This provided the opportunity to see two ISS cargoships, one departing and one arriving, in the sky last week.

And it continues: we are in anticipation of the Crew Dragon Demo-2 launch, on May 27 if weather cooperates (see my previous blogpost), bringing to astronauts to the ISS.

Both Cygnus NG-13 and HTV-9 made some splendid evening passes last week. Weather was clear on most days, allowing me to observe and photograph several passes, often two on one evening. Through Twitter, I managed to get a lot of people to go out and watch the passes. HTV's are very bright and distinctly orange objects, easily visible with the naked eye even in deep twilight and from an urban environment. So they are ideal objects to get people out and watch.

HTV-9 was a spectacular sight on every pass. It reached magnitude 0 to -1, with a very distinct orange colour that is due to the orange thermal foil it is wrapped in. It was also prone to producing brief bright flares to magnitude -2 to -3. It did this on almost every pass, sometimes multiple times. here is an example, from May 21:

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Below are a number of photographic stacks I made during these HTV-9 passes (gaps in the trails are the brief periods between successive photographs in the stack). The first image showing another flare: the second bright satellite crossing the path of HTV-9 in the third image is Resurs P1. Note the orange colour, especially apparent in the second image. Visually, the orange colour was even more profound than in these images (where they have washed out a bit due to the brightness of the trail).

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Cygnus NG-13 was much fainter than HTV-9. During a  good pass it would reach magntude +3, but often was below naked eye visibility. Here is imagery from one of the brighter passes, on May 19 when it reached magnitude +3:

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More images of Kounotori (HTV) 7

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The image above is a stack (combination) of six images, taken at 10-second intervals with a 5-second exposure (Canon EOS 60D + EF 2.0/35 mm, 800 ISO). It shows Kounotori HTV 7 (2018-073A), a Japanese cargoship on its way to the ISS launched on September 22. This image was taken some 17 hours before it berthed to the ISS.

The cargoship was about 1m 38s behind the ISS at the time of observation. As no recent orbital elements were available, I did not know where to expect it relative to the ISS, so I started watching well before the ISS pass, and next noted it ascending over the roof just after the ISS had disappeared in Earth shadow.

The HTV 7 spacecraft was very bright during this pass: near magnitude +1, and a very easy naked eye object. Just like the day before (see an earlier post), it flared brightly, to at least mag -1/-2 at 19:50:18 UT (26 Sep 2018). The flare can be seen on the composite image above, and on the single image from this series below:

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Also note the distinct orange colour of the trail, which is due to the fact that HTV 7 is wrapped in gold-coloured insulation foil.

The flare happened while HTV 7 was passing through the field of view of my video setup:

The image below is a composite of the images taken while the ISS passed, and the images of HTV 7 passing 1m 38s later (i.e., they didn't move this close in the sky in reality!). The orange colour of HTV 7 stands out. Also well visible is that HTV 7 was somewhat faster than the ISS, due to a difference in orbital altitude (and hence orbital period):

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Imaging a pass of Kounotori (HTV) 7 on it's way to the ISS

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On 22 September 2018 (and after several launch delays, amongst others due to a typhoon), at 17:52:27 UT, Japan's Space Agency JAXA launched Kounotori (HTV) 7, a cargoship destined for the ISS. It will dock to the ISS tomorrow on September 27th.

The 9.8 x 4.4 meter HTV (HTV stands for "H-II Transfer Vehicle". The name Kounotori stands for "white stork") are easily visible, bright objects with a distinct orange colour due to the use of gold-coloured insulation foils.  See the image below of HTV 7 being assembled at the Test and Assembly Building at Tanegashima Space Center before launch:

image: JAXA

After days with bad weather, the sky cleared yesterday. I had a low pass in the southwest near 19:18 UT (Sep 25) and went to the nearby city moat with my camera, as I have a better view lower at the horizon there. Some whisps of thin clouds still lingered in the sky.

First, at 19:04 UT, I watched HTV 7's destination, the International Space Station (ISS), sail past as a very bright object. The image below is a stitch of two image stacks (!): one stack of two images, and a stack of 4 images with the camera FOV shifted horizontally. Camera: Canon EOS 60D with an EF 2.0/35 mm lens. I used exposures of 4 seconds at ISO 800.

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Then  I waited for HTV 7. As the latest orbital elements at that point were almost a day old, I was not sure about the exact time it would show up.

Some 14 minutes after the ISS it emerged, clearing the trees and houses low at the southwest horizon, and to my surprise and joy featured a bright flare to at least magnitude -1. My first image just captured the end of this brief flare (first of the two images below):

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The object was easily visible with the naked eye and had an orange hue. The image stack below was made of 5 images taken at 10-second intervals, with each image a 4-second exposure (camera details the same as for the ISS image). It shows HTV 7 from the bright flare to the moment it disappeared in the Earth's shadow:

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Space Shuttle Discovery STS-128

Yesterday it was a close call whether I would see the Space Shuttle Discovery STS-128 or not. A large field of clouds passed in late twilight, and only moved away some 10 minutes before the Shuttle pass. The clouds made me miss the newly launched Japanese HTV cargo ship to the ISS.

But the clouds moved away in time, and there it was: about mag. +2 to +2.5 and fast, and...39 seconds early on predictions based on orbital elements of earlier that day.

Three minutes later, the ISS sailed by in its majestic fashion.

The image below shows the shuttle passing through Ophiuchus.

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