Falcon 9 Flight 20 has successfully deployed 11 ORBCOMM satellites into orbit. I can easily imagine a rocket deploying 1 or 2 satellites. But how did Falcon deploy 11 satellites in a single flight?

Even if they orbit at the same altitude I expect they have to be properly spaced between one another. Is the answer specific to Falcon 9, or even to this particular launch?

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    $\begingroup$ I was going to say, one at a time. But actually it was two at a time. $\endgroup$
    – geoffc
    Commented Dec 23, 2015 at 13:43
  • 1
    $\begingroup$ Also worth noting that these satellites were relatively small. $\endgroup$ Commented Dec 23, 2015 at 19:36

2 Answers 2


In the webcast, you can see the mechanism that deploys the satellites:

Deploying the Orbcomm constellation

The satellites are attached to the sides of a tower structure. They are probably held in place by clamps. When the clamps release, a spring pushes the satellite away from the rocket.

For an earlier launch, a similar tower looked like this:
Orbcomm 2

The satellites all share the same orbit. After launch, the satellites will use their own engines to achieve the proper spacing in this orbit.


  • $\begingroup$ Both answers here are burying the lede: the satellites will get into their final orbits under their own power. $\endgroup$ Commented Dec 23, 2015 at 16:35
  • $\begingroup$ That's the last step in the sequence, so leading with that just confuses things. $\endgroup$
    – Hobbes
    Commented Dec 23, 2015 at 16:40
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    $\begingroup$ The i.sstatic.net/luNB3.png photo is a bit confusing, because it shows multiple orbital tracks. SpaceX placed all 11 satellites into a single orbital plane, and the satellites will use their own thrusters to perform phase adjustments and spread themselves out over time. $\endgroup$ Commented Dec 23, 2015 at 20:29

A few additional points.

  1. The satellites were deployed 2 at a time, to keep the rocket from tipping while deploying.
  2. The satellites were on a spring system, as can be seen. They were held seem to be held on by a few bolts, as can be seen in the below image, of what looks like a vibration test.
  3. I suspect they were deployed at various angles to keep them apart. The video shows fairly clearly (Focus on the moon) that the rocket rotated after each deployment, likely to send them at different angles
  4. There exist different strengths of springs.
  5. Each pair of spacecraft goes in opposite directions.
  6. After deployment, the spacecraft will use their thrusters to properly space. I suspect this will be done similar to how the previous satellites were done.
  7. It seems the tower is known as a Satellite Dispenser, and is provided by Moog. Specifically, the tower is build from a number of ESPA rings (Secondary Payload Adapter), and they provided the harness and other wiring as well.
  8. Of some note are the size of these satellite. These satellites have 172 kg mass. Time 12 (For the mass simulator), that's 2064 kg. The mass to LEO for the Falcon 9 is about 13500 kg. Even with the support structure, that's 10,000 kg surplus in capacity. Compare the size of the structure on the bottom of the SES launch (Pictured below) to that of the ESPA ring. Note the diameter of the rings is the same. SES easily fit inside the fairing, and I suspect even with 3 stacks high, the OG2 satellites only are about 1/5th the height of SES inside the fairing.

It's pretty standard fair that the rocket company does analysis to make sure the satellites won't recontact each other for a specified time post-launch.

OG2 during testing

SES inside fairing


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