Can someone explain (in general or specific terms) how SpaceX deployed these 10 satellites? I'm trying to imagine the mechanisms and process of launching these objects with the required precision. Is there a satellite "dispenser" of some sort (a "tube") with these objects stacked up inside?

Update: I read the possible duplicate question but it didn't go into the actual mechanism(s) involved or provide any details about how this sort of precision launch is accomplished (e.g. a servo spins up the object to a specified rotation speed and then...). (I didn't watch the linked webcast).

SpaceX Returns to Flight with 10-Satellite Launch, Rocket Landing

SpaceX's two-stage Falcon 9 rocket lifted off from a launch pad just a few hundred meters from the scenic California coastline here today at 12:54 p.m. EST (1754 GMT; 9:54 a.m. local California time), carrying 10 communications satellites to low-Earth orbit for the Virginia-based company Iridium. After a week of heavy rain and strong winds, only a few clouds obscured the view of the rocket as it climbed skyward.

Deployment of the satellites began 59 minutes after liftoff and took about 15 minutes, SpaceX representatives said.

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    $\begingroup$ Possible duplicate of What pattern and method of satellite release will the pentagonal Iridium arrangement use? $\endgroup$ Jan 16, 2017 at 7:39
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    $\begingroup$ I agree with @NathanTuggy, this does look like a duplicate. Both are questions about the mechanism (method) and process (pattern), i.e. how are the sats deployed, and when/in which positions. $\endgroup$
    – Hobbes
    Jan 16, 2017 at 8:48
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    $\begingroup$ @uhoh: In particular, I think the answer you got is a lot less complete than could reasonably be given, and all or substantially all the answers that could be given here would probably be of some merit over there. $\endgroup$ Jan 16, 2017 at 9:07
  • $\begingroup$ @NathanTuggy et al - ok I'll defer to my seniors :) I've removed the word "method" from my previous question and I have now asked the big one. $\endgroup$
    – uhoh
    Jan 16, 2017 at 10:35

1 Answer 1


SpaceX knows from the time they are getting in to the detailed mission plan the number of satellites, and where they will be on the spacecraft. The stack looks like below (Source) enter image description here

Given that there were 10 satellites, I imagine they are in a pentagon formation. Each of these satellites is mounted by a few points, usually 4 or more, with springs loaded to them. There is also a cable that is attached together such that it can be detached without any damage, to connect it to the satellite. You can see an example from the very similarly mounted Orbcomm satellites. There are a number of such pictures here.

enter image description here

There is also a photo that shows the satellite attached at 4 points, most likely for a vibration test, although that isn't clear.

enter image description here

Basically what happened is the rocket commanded each of the satellites to be released at a certain time. I'm not sure of the exact latching mechanism, likely it was a kind of exploding bolt. When it was released, the satellite would be accelerated by the spring and leave the rocket behind.

SpaceX will have done an analysis to figure out the proper orientation of the rocket when deployed. There is a particularly funny phenomena in orbital mechanics where something that is moved faster actually will orbit slower, so all of the objects will switch in orbit very early on, within the first orbit usually. SpaceX will have done the simulation to show that there is no chance that these objects will "recontact" during that period of time.

The rocket will try to remain as still as possible during the deployment, at it's assigned orientation. There may be a slight "tip off" rotation that is induced during the deployment, but this is taken in to account during the planning of the sequence.


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