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