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In the orbitalreflector.com website there is a picture of a ring that looks like it can deploy smallsats as part of a more complex launch. Reverse image search turns up another view, both shown below.

It reminds me a lot of SHERPA (What ever happened to SHERPA?) but is it an artist's conception, or a fairly accurate rendering of something that SpaceX will use to deploy small spacecraft?

below: cropped from here.

enter image description here

below: from here.

enter image description here

uhoh
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  • @Muze yep, good eyes! That's why I called it an "artist's conception, or a fairly accurate rendering". – uhoh Sep 25 '18 at 15:58

1 Answers1

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Both spacecraft appear to be utilizing an ESPA ring, which stands for EELV Secondary Payload Adapter.

ESPA class missions "hitchhike" on the interstage of a larger launch. This is useful when e.g. a telecom company needs to buy a launch to the GEO belt (which traditionally requires a larger launch vehicle), but don't need all of the rocket's capability. Selling the remaining upmass to another mission helps both parties. The primary mission saves money, and many ESPA missions are projects that could not otherwise obtain a launch.

The original ring was developed by Moog in the early 2000s. These days it has become more of a standard than a product, and several companies manufacture ESPA class busses including Northrup Grumman (formerly Orbital ATK).

An example of an ESPA class mission that is currently flying is AFRL's EAGLE.

Bear
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  • So this ring gets deployed from the interstage, and all the payloads on the ring stay together? Or can the payloads be launched from this ring? – Hobbes Sep 24 '18 at 13:49
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    @Hobbes both are possible. The linked article about EAGLE mentions a deployable, and the linked Moog page mentions a product called CubeStack, which has a total of 12 cubesat adapters. – Bear Sep 24 '18 at 13:56
  • Thanks! The images in the question are artwork or CAD at best, as is the image in my linked question about SHERPA. Has one of these actually been deployed in space for sure? Or are these all concepts and development projects? – uhoh Sep 24 '18 at 14:14
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    @uhoh EAGLE has been deployed off of AFSPC-11, as have at least 3 other rings on Orbcomm launches. Are you looking for on-orbit imagery of vehicles-as-deployed? I would be surprised if this exists - the upper stage doesn't generally have Rocketcam or anything like that. – Bear Sep 24 '18 at 15:31
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    @Bear For some reason I missed the last and obviously most important link. So Eagle is this? https://space.skyrocket.de/doc_sdat/eagle.htm 2018-036B, NORAD 43340? I'm finally getting the picture I think, thanks! – uhoh Sep 24 '18 at 15:45
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    Yup, that's the one! – Bear Sep 24 '18 at 15:54
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    I'll add that new USAF policy is to use each defense launch at full capacity. The use of ESPAs is very likely to spike in the coming years. – ChrisR Sep 25 '18 at 03:21
  • possibly helpful: Spaceflight Inc Evolving Sherpa for Future Rideshare Missions – uhoh Jul 22 '20 at 08:42