Posted by: Szabolcs Nagy Comments:0
SpaceX CRS-21 and Falcon 9 upper stage (21 minutes after launch)
The past few months were something I haven’t really experienced since started photographing the International Space Station. Almost constant cloud cover and the few clear days were somehow always out of sync with ISS flyby events. This ‘out of action’ time made me feel less assured about my photographing capabilities. When the opportunity arouse for a possible event of the freshly launched CRS-21 cargo spacecraft flyby, I was happy but also a bit worried as well.
On top of it I am now actively running a hungarian webcast, we talk about events and broadcast live rocket launches. We were covering this particular launch, so I already had to have my setup almost fully ready for action – except focusing due way too bright sky, I was still just after sunset).
The flyby event was expected 21 minutes after launch (at around 16:38UT). Approximately 10 minutes after launch I stormed out to my garden, where I had to still perform focusing with Bahtinov mask. Of course I left way little amount of time for myself, had some aligning/focusing issues. I was still setting the correct expo/gain values when I spotted a fast moving bright spot in the sky at the correct direction. Not ideal!
I rapidly loosened the dobson mount and started recording (I lost a good 20-30 seconds of valuable time from the event) and started recording. The bright object reached its maximum elevation at around 50-60° above horizon and on my photos the object was already receding fast.
Eventually I only captured 7 frames with objects on them and 5 was good enough quality worthy to keep for an animation (recorded at 16:38:55UT).
I was happy to see two objects closely together on my frames. This animation consists of 5 consecutive frames and they cover a timespan of 0.1 second slightly slowed down. Seeing the Falcon 9 upper stage luckily not a new thing, I had similar experience during the Starlink-7 launch back in April last year.
The object on the left hand side is the CRS-21 cargo spacecraft. This is the new Dragon-2 version spacecraft from SpaceX performing its first operative cargo flight to the ISS. On the right hand side that is a Falcon 9 rocket’s second or upper stage. Most likely it was carrying out its 180° turn around manoeuvre, engine nozzle pointing toward 12 o’clock on the photo. I only guess the manoeuvre was half way done due to the orientation of the upper stage. The turn around manoeuvre is essential for the following so called deorbit burn. It will fire its vacuum optimised Merlin engine to decrease its own velocity. This way this particular upper stage spends very little time on Low Earth Orbit and burns up somewhere over the Indian Ocean near Australia.
I haven’t figured it out what that little extension on right hand side of the Dragon vehicle could be. It is more visible on the animation, to me it looks like the nosecone, but not sure about that at all. I only wonder what could be large enough to be visible on the photos – fin, nosecone, maybe thruster activity (less likely) and that’s it. If you have any idea, please let me know about it.
Also the Falcon 9 upper stage has a highly reflective cover around the narrower end of engine nozzle, I think that’s why the top section of the rocket stage seems to be much brighter relative to rest of the rocket.
And finally this photo here is an original frame (no crop, original resolution, slightly post processed).
Skywatcher 250/1200 Flextube dobson telescope
Zwo ASI224MC camera
TeleVue 2.5x powermate