Tuesday, 9 October 2018

Falcon 9 reentry burn from SAOCOM 1A launch observed from Europe

image (c) Koen Miskotte. Used with permission
click image to enlarge
On 8 October 2018 (7 October local time) at 2:21 UT, SpaceX launched the Argentinian Radar surveillance satellite SAOCOM 1A (2018-076A) in a sun-synchronous ~620 km orbit. The launch took place from launch platform 4 at Vandenberg in California. It was a spectacular launch, yielding spectacular launch images.

An hour later, near 03:40 UT, a bright fuzzy blue object travelling through the sky was seen from northern Europe.

This fuzzy phenomena was the Falcon 9 rocket stage (the 2nd stage) form this launch performing its re-entry burn while passing through apogee, lowering perigee such that it would reenter into the atmosphere over the Pacific Ocean southeast of Hawaii near 04:13 UT, at the end of it's first revolution.

The image above is part of an image taken by a photographic all-sky meteor camera in Ermelo, the Netherlands, operated by Koen Miskotte. It is actually a stack of 4 separate images (hence the three short breaks in the trail), of 88 seconds exposure each, taken between 03:39:30 and 03:45:28 UT on Oct 8, 2018. The bright blue fuzzy streak above the treeline is well visible.

The map below shows the trajectory of SAOCOM 1A during the first revolution. It passed over eastern Europe around 03:40 UT (in making this map I used the orbit of the payload as a proxy, as there are no orbital elements of the rocket stage. At this stage of the launch, the rocket stage will have been close to the payload in a similar orbit).

The map also depicts the deorbit area near Hawaii. The deorbit burn initiating the de-orbit happens about half a revolution earlier (some 45 minutes before reentry) in apogee of the orbit, i.e. over Europe:

click map to enlarge

A surveillance camera from a weather station in SüderLügum in Germany, near the German-Danish border, produced this spectacular time-lapse movie of the event (note the "puffs when the rocket engine is firing):

The sky map below shows the trajectory for SAOCOM 1A for Ermelo, the location of Koen Miskotte's alls ky camera (times are in CEST = UT +2). The full all sky image is given as comparison. The two match well:

click map to enlarge
image (c) Koen Miskotte. Used with permission
click image to enlarge


jim oberg said...

Even clearer images were obtained for the
Falcon-9 stage 2 deorbit on Feb 19, 2018
from Norway and nearby. They show that
the burn began with the twin-lobed
conditioning purge creating an 'up'
and a 'down' cloud [also visible at
the very start of the new video] and
followed by an approx. 2-second burn.


The same sequence is even clearer in the images of
the stage-2 reignition Feb 6 for the trans-Mars
insertion of the Tesla roadster. Of course
THAT burn was much longer than for deorbit, and
in the opposite direction as clearly shown.


jim oberg said...

I checked cloud cover and sunrise times, and there was a coastal pocket in Norway, plus Finland and NW Russia and Iceland, plus trans-Atlantic air traffic, that should have had good chances of spotting the plume.

jim oberg said...

Another report, not yet verified, posted on youtube -- "Psycho Stef == A friend just told me monday morning around 6.00am he has seen a circular teleportation-like cloud with a very fuzzy object close to it of coming out of it about 30 meters in the sky and about 1 km away. Some online sources told him it was the Falcon 9 rocket launch he saw, where he knew nothing about. Only thing is, we live at the Belgian coast (on the other side of the 'world', that is) and the thing he saw was very close and stationary until it dissapeared. "

jim oberg said...

Positive results from a Iceland all-sky camera, details to follow.

jim oberg said...

And a suggestive report from Yorkshire:

[comment posted on https://youtu.be/sEaTe38-I4Y
placid renegade == Not sure if I saw this happen this morning! I'm from the uk and watched something very much like this around 3am in the morning sky.

Just realised I was in fact looking east from West Yorkshire, the back of my house faces direct north so I looked to my right (east) I watched what at first thought was the moon behind clouds but as it was much much smaller. But it had that look of when the moon is behind whispy clouds, looked much larger than the stars in the morning sky. It was roughly about the height of the moon in the morning sky but as I watched it more and more it diminished and definitely dropped and veered to its left, as doing so looked like an actual star size then disappeared. I wondered if I had witnessed a supernova or something. And when morning came I searched the Internet to see if anyone else had reported it also, then came across info on Twitter about this.
[sent my report on Feb 2018 Norway obs of deorbit burn]
yeah no doubt about it mate, how it looks on the images is what I watched, it's the exact same size and around the height I witnessed. The whispey natured like emitting a large gas halo is what I can best describe it as. Feel very honoured now to have witnessed this. I must admit though it didn't have a core like the images as it was very far away, more like a torch shine in fog.

jim oberg said...

Witness report from Belgium:

Datum: 08-10-2018 Plaats: Pittem (West-Vlaanderen) Tijdstip: 5u50
Waarnemingsduur: 5 minuten
Omstreeks 5 u 50 keek ik naar sterrenbeeld "de grote beer" en plots zag ik aan de anders heldere hemel, je zag goed de sterren en ook een tweetal vliegtuigen, een bolvormige mistvlek met daarin een helderwit licht. Ik dacht eerst een ster of een vliegtuig achter een wolk, maar de rest van de hemel was helder en je zag heel goed de bolvormige mistvlek die bewoog. Ik nam de verrekijker en zag in het midden een helderwit licht, heel fel en de mistbol werd iets groter en het was alsof er een zoeklicht bewoog doorheen de mistbol, je zag een soort lichtbundel. De bol bewoog van het oosten naar het noorden en daalde iets en werd soms groter en kleiner terwijl het licht ook wat veranderde, de snelheid was redelijk constant en een beetje zoals van een vliegtuig.

Around 5:50 I watched the constellation Ursa Major and suddenly I saw the otherwise clear sky, you saw the stars well and also two planes, a spherical mist spot with a bright white light. I first thought of a star or a plane behind a cloud, but the rest of the sky was clear and you could very well see the spherical mist that moved. I took the binoculars and saw a bright white light in the middle, very bright and the mist bulb became slightly larger and it was as if a searchlight was moving through the mist, you saw a kind of beam of light. The sphere moved from the east to the north and dropped slightly and sometimes became larger and smaller while the light also changed slightly, the speed was fairly constant and a bit like a plane.