As I was watching the SpaceX launch today on YouTube, I have noticed a bright distant light as the satellites were being deployed. What was that light?

enter image description here

Also, after each deployment there was something white and small flying away from the main body. What was that?

  • $\begingroup$ There was some debris seen drifting away which is probably pyrotechnic bolts holding the satellite deployment mechanism. $\endgroup$
    – Juancho
    Dec 22, 2015 at 2:06
  • $\begingroup$ The only reason I don't think it was the moon is it tracked off the frame far too slowly. $\endgroup$
    – Joshua
    Dec 22, 2015 at 2:07

1 Answer 1


It was the Moon. It was illuminated at roughly 85-86% as seen from low Earth's orbit at the time of deployment, so pretty bright, and roughly directly overhead of the Americas. Deployment camera was pointing more or less backwards with respect to upper stage's velocity vector and the upper stage was tracking roughly over the Atlantic ocean West of Europe 17 minutes into the launch. Earth's, Moon's and Sun's geometry, made with Solar System Scope orrery for exact time and in realistic size mode centered on Earth, looked like this:

             enter image description here

Note that how the Moon appears to track relative to the camera's frame also depends on upper stage's own attitude during deployment, not just orbit's geometry. Its orientation relative to the Earth would slightly change in between each deployment stage. To appreciate this easier, here's the video at roughly the time that the image in your question displays:

Short of having an officially made ground track so we can see precisely over which area Orbcomm OG2 satellites were deployed, here's a simulated ground track, made with Flight Club simulator that should be fairly close to the real deal:

enter image description here

Small things flying away from the main body are mostly transient debris from the upper stage and payloads themselves, things like droplets of hydraulic fluid or actuators pressurization gas (depending on design) for the stage engine's gimbals, lubrication oils of the deployment system to prevent cold welding (stiction) of similar metallic surfaces or friction of the spring release mechanism, residual fuel from reaction control system thrusters firing up, ice condensed on cryogenic surfaces now exposed to vacuum chipping off as its surface starts outgassing, and similar volatile fluids that would "bake-off" and disperse in the heat of sunlight as soon as their orbit enters daylight (at that altitude, one orbit is approximately 97 minutes long). And some of it would be camera noise and you're seeing ionizing radiation striking its sensor.

But short of an unexpected event, there wouldn't be many, if any at all long-lasting orbital debris released by the deployment mechanism or the upper stage itself once they've all reached orbital speed, since a lot of effort is made to reduce the number and long lasting impact of orbital debris. But if there will be any, we'll see soon enough either via NORAD Orbital Debris Catalog and/or UNOOSA Index of Objects Launched into Outer Space, which is a registrar that all member state parties to the Outer Space Treaty report to.

  • $\begingroup$ I've asked a follow-up question here $\endgroup$
    – uhoh
    Jan 13, 2016 at 9:58
  • 1
    $\begingroup$ @uhoh Cool, but I don't know that and I doubt that the stage rotated for deorbit before deployment. I'm discussing here camera's orientation, not the stage's. SpaceX is known to place cameras nearly everywhere, including inside the propellant and oxidizer tanks, and even on payload fairing sections (tho the latter ones were not broadcasting and the camera's card was recovered by some holidaymakers, but there are more interesting distant objects to see there, inc. the Moon, other half of the fairing, the upper stage thrusting away, Venus,...). $\endgroup$
    – TildalWave
    Jan 13, 2016 at 17:29
  • $\begingroup$ Thanks @TildalWave! Take a look at the additional image, link, and discussion I added there. $\endgroup$
    – uhoh
    Jan 14, 2016 at 1:04

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