SpaceX has just announced their new smallsat rideshare program. Is it known how many satellites can be launched at once? Any estimates?


From that same page:

enter image description here

Those are ESPA rings, for EELV Secondary Payload Adapter.

The initial ESPA ring was designed to support a 15,000-pound (6,800 kg) primary payload and up to six 400-pound (180 kg) secondary payloads. Each secondary spacecraft is mounted radially on a 15 inches (380 mm) diameter port and is allocated 24 inches (610 mm) × 28 inches (710 mm) × 38 inches (970 mm) volume. This has led to the colloquial designation of ESPA-class payloads.

One spot on the ring can be occupied by a small satellite, or by a cubesat dispenser.

the image also shows a different ring:

ESPA Grande - The "stretch" version of the ESPA Ring, accommodates four 300-kg secondary spacecraft on 24-inch ports.

The rings can be stacked as required.

The F9 User Manual has not yet been updated, but that's the place where I expect more details on what combinations are possible, will appear.

As for an estimate: there are a bunch of variables that would lead to different estimates. The payload is either mass-limited or volume-limited depending on satellite mass, etc.

  • $\begingroup$ Three rings of six makes 18, might that be the answer to the question "...how many smallsats fit?" or can there be four rings stacked, or even more? $\endgroup$
    – uhoh
    Aug 6 '19 at 9:06
  • 1
    $\begingroup$ I think more will fit, depending on satellite size you can use more of the height in the fairing (the cone section at the top only accepts smaller payloads), and there are 4 different ESPA rings with varying heights. But that's all speculation until SpaceX updates their user manual. csaengineering.com/content/dam/moog/literature/Space_Defense/… $\endgroup$
    – Hobbes
    Aug 6 '19 at 9:14

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