Pez-dispenser Starship as Rideshare provider?

[mikelepage]

Now that we've seen Starship deploy dummy starlink v3s using their pez dispenser arrangement, it seems reasonable that the v3 starlink satellite form factor could become a new industry standard if SpaceX decides it's worth supporting.

Similar to the growth in the use of cubesats once that form factor became standard, or even the larger form factors allowed by F9 rideshare, you could see full-size (~7m x ~7m) or half-size (~7m x ~3.5m) satellites become pretty popular, given how often SpaceX already plans to launch new satellites for Starlink. One in every so many flights could be dedicated to Rideshare, as it is now with F9.

I'm curious what potential use cases people can imagine. I'm guessing the tricky part is that each satellite can only be 20-30cm wide? I'm toying with my own concept for an orbital terrarium, but I'm sure there are plenty of others.

[catdlr]

For context, I want to give members a brief overview of previous proposals and the current design of this project, specifically in terms of size and shape.  Something to get a foothold and get the right mindset.

ARTICLE:
The PEZ Dispenser: Starship's Payload Deployment System

Tweets:
https://twitter.com/thesheetztweetz/status/1244964102033866758

VIDEOS:

[geza]

Good point. I guess many of the Starshield statellite will have such form factor also. If commercial demand exist, SpaceX can provide satellite buses of this type. The consumers should build only their specific systems; power, attitude control and communication via Starlink will be handled by the bus.

My first thought was that this form factor exclude a telescope wider than 20-30 cm. But I've solved . Take the half-size form factor. A mirror with diameter ~ 3 m occupies the half of the satellite. The focal equipment, etc. should be stored in the other half during launch and be deployed on orbit. The tube can consists of soft material and be deployable. Maybe, a full-size satellite can accomodate a 6 m telescope?

Beyond science and reconnaissance, such telescope will be needed for interplanetary optical communication, anyway.

[meekGee]

Good point. I guess many of the Starshield statellite will have such form factor also. If commercial demand exist, SpaceX can provide satellite buses of this type. The consumers should build only their specific systems; power, attitude control and communication via Starlink will be handled by the bus.

My first thought was that this form factor exclude a telescope wider than 20-30 cm. But I've solved . Take the half-size form factor. A mirror with diameter ~ 3 m occupies the half of the satellite. The focal equipment, etc. should be stored in the other half during launch and be deployed on orbit. The tube can consists of soft material and be deployable. Maybe, a full-size satellite can accomodate a 6 m telescope?

Beyond science and reconnaissance, such telescope will be needed for interplanetary optical communication, anyway.

You just invented the bellows....

[DanClemmensen]

Pez can probably handle a double-wide satellite in addition to the standard Starlink V3, so roughly 7 m square. This requires a bit more customization of the bus than a "standard" V3 bus, especially in the propulsion and control.

[DanClemmensen]

This scheme also allows for a rideshare-in-rideshare scheme. This uses a V3 bus to provide services to a whole bunch of cubesat-type modules.

[DanClemmensen]

Note that  one Pez Flight can handle both Starlinks and rideshares, so SpaceX does not need to accumulate an entire Starship's worth of rideshares. For rideshares that don't care about the exact orbit, there will be launch opportunities every week. For rideshares that are less flexible on orbits, the customer may still be able to negotiate a compromise orbit that SpaceX is willing to fill out with Starlinks.

[Twark_Main]

Good point. I guess many of the Starshield statellite will have such form factor also. If commercial demand exist, SpaceX can provide satellite buses of this type. The consumers should build only their specific systems; power, attitude control and communication via Starlink will be handled by the bus.

My first thought was that this form factor exclude a telescope wider than 20-30 cm. But I've solved . Take the half-size form factor. A mirror with diameter ~ 3 m occupies the half of the satellite. The focal equipment, etc. should be stored in the other half during launch and be deployed on orbit. The tube can consists of soft material and be deployable. Maybe, a full-size satellite can accomodate a 6 m telescope?

Beyond science and reconnaissance, such telescope will be needed for interplanetary optical communication, anyway.

You just invented the bellows....

This is really gonna help with my traveling daguerreotype business! 


(naturally for a telescope the bellows would be parallel, but the hardest part is having an ultra-rigid deployable frame that's as lightweight as possible)

[AmigaClone]

This scheme also allows for a rideshare-in-rideshare scheme. This uses a V3 bus to provide services to a whole bunch of cubesat-type modules.

It also might allow a variant of the V3 bus to deploy cubesats either above or below where the Starlink satellites are deployed.

[DanClemmensen]

This is really gonna help with my traveling daguerreotype business! 

(naturally for a telescope the bellows would be parallel, but the hardest part is having an ultra-rigid deployable frame that's as lightweight as possible)

Maybe, but in microgravity, a less rigid frame with active alignment might be more feasible. You only need to re-align after retargeting the system. Active alignment using laser interferometers and piezoelectric actuators should be more precise than an ultra-rigid frame.

[StraumliBlight]

GeekWire: Starcloud plans its next power plays after training first AI model in space [Dec 22]

“From there, we scale up to Starcloud-3, which is about a 2-ton, 100-kilowatt spacecraft that will launch on the Starship ‘Pez Dispenser’ form factor,” he said. “So we can launch many of those.”

[geza]

Good point. I guess many of the Starshield statellite will have such form factor also. If commercial demand exist, SpaceX can provide satellite buses of this type. The consumers should build only their specific systems; power, attitude control and communication via Starlink will be handled by the bus.

My first thought was that this form factor exclude a telescope wider than 20-30 cm. But I've solved . Take the half-size form factor. A mirror with diameter ~ 3 m occupies the half of the satellite. The focal equipment, etc. should be stored in the other half during launch and be deployed on orbit. The tube can consists of soft material and be deployable. Maybe, a full-size satellite can accomodate a 6 m telescope?

Beyond science and reconnaissance, such telescope will be needed for interplanetary optical communication, anyway.

You just invented the bellows....

My next interest is to launch together several (many?) pez-telescopes and ask them to cooperate. One possibility is to manuver them side-by-side and secure them together mechanically to form a sinlge large mirror. The other, more demending, one is to fly them separately and doing optical interferometry.

Note that large space telescopes will be needed for interplanetary optical communication, anyway. Instead of an expensive one-of telescope, they will be need them in quantity and at a relatively low price. I am sure that Elon & Co. are busy to study the problem. I am looking for the astronomical applications, for Earth-like planets around G-type stars, etc.

Note that the LISA project for space gravitational wave detector is about something simliar: https://arxiv.org/abs/2402.07571

[Paul451]

My next interest is to launch together several (many?) pez-telescopes and ask them to cooperate. One possibility is to manuver them side-by-side and secure them together mechanically to form a sinlge large mirror. The other, more demending, one is to fly them separately and doing optical interferometry.

Perhaps the Pez form-factor lends itself to "strip" telescopes. A narrow slice of a parabolic mirror for the primary, which gives you resolution (element separation) only in that plane. Ie, it produces a 1D image, instead of the normal 2D. (You can rotate the whole telescope to image different planes.) Bad for imaging, but good for things like planetary spectra where you need to separate the planet's light from the star's light, but don't care about the "image" as such.

If the v3 Starlink, hence the Pez launcher, is 7m wide, you might get a 6m strip mirror within a pizza-box surround. The surround is open only on one narrow end, which also supports the secondary mirror.

If the online description of 3.5x7m is correct, you might need the longer dimension for mirror separation. So a 2-3m primary, with the light path down the long axis. Hubble "resolution", within the limitation of the strip imaging architecture.

Alternatively, dock three or four "boxes" together, flat end-to-end, after deployment, to provide greater distance between primary & secondary, and get the full 7m width.

Being "Pez", you can aim for mass production, throwing a bunch into orbit for a variety of observers. That excess allows long exposure and bulk-survey studies, both of which are hard to get time on observatories like JWST, due to the large time requirement.

[DanClemmensen]

GeekWire: Starcloud plans its next power plays after training first AI model in space [Dec 22]

“From there, we scale up to Starcloud-3, which is about a 2-ton, 100-kilowatt spacecraft that will launch on the Starship ‘Pez Dispenser’ form factor,” he said. “So we can launch many of those.”

We have speculated about Pez rideshare here on this forum. Is this the first mention of it by SpaceX or an actual third-party customer?

[TheRadicalModerate]

I tried starting this discussion back in spring and didn't get much traction.  I think the most important insight that came out of that exercise was, if you can get the pez dispenser to be versatile enough, the chomper can go away.

I can think of five possible models for generic pez, most of which can coexist with one another:

1) Plain ol' Starlink v3's with funny software.
2) Starlink v3 buses with different payloads.
2a) A v3-dimensioned container, which can hold and deploy multiple cubesats.
3) A non-v3 bird with v3's dimensions and physical interfaces.
4) A more flexible pez that can be sized to accommodate a limited range of different dimensions.

The big big big big advantage of pez is the simplification of payload processing:  you integrate your birds into a cassette in the payload processing cleanroom, then the cassette is transported to the pad, where the contents of the cassette are fed into the Starship, without compromising cleanliness.

You'll still need a solution for the occasional extremely bulky satellite (e.g. things with wide/long optical trains, space station components, etc.) but an expendable Starship with jettisonable fairing might be fine for those cases.  This also reduces the payload processing model to something with which the manufacturers and operators are comfortable:  put the payload on its PAF, integrate it in the clean room, encapsulate it in the fairing, and load the whole nose onto the vehicle.

I'm very skeptical of chomper.

[meekGee]

I tried starting this discussion back in spring and didn't get much traction.  I think the most important insight that came out of that exercise was, if you can get the pez dispenser to be versatile enough, the chomper can go away.

I can think of five possible models for generic pez, most of which can coexist with one another:

1) Plain ol' Starlink v3's with funny software.
2) Starlink v3 buses with different payloads.
2a) A v3-dimensioned container, which can hold and deploy multiple cubesats.
3) A non-v3 bird with v3's dimensions and physical interfaces.
4) A more flexible pez that can be sized to accommodate a limited range of different dimensions.

The big big big big advantage of pez is the simplification of payload processing:  you integrate your birds into a cassette in the payload processing cleanroom, then the cassette is transported to the pad, where the contents of the cassette are fed into the Starship, without compromising cleanliness.

You'll still need a solution for the occasional extremely bulky satellite (e.g. things with wide/long optical trains, space station components, etc.) but an expendable Starship with jettisonable fairing might be fine for those cases.  This also reduces the payload processing model to something with which the manufacturers and operators are comfortable:  put the payload on its PAF, integrate it in the clean room, encapsulate it in the fairing, and load the whole nose onto the vehicle.

I'm very skeptical of chomper.

What's so hard about a large door / chomper?

It only has to open and close during zero stress, sealing (if you want to use structural pressurization) can be leaky, the split line doesn't have to reach the front and can be less than 180 degrees with almost no penalty.

But yeah the pez arrangement is obviously awesome for constellations.

[TheRadicalModerate]

What's so hard about a large door / chomper?

1) Unlike Pez, where the launch stresses can be routed around the Pez door, the chomper door has to be load bearing, then still open (and close!) after bearing the load.

2) Spin-stabilized deployment is really, really weird:
a) Open chomper.
b) Tilt payload out.
c) Spin tilt table up??
d) Deploy bird without hitting anything.
e) Spin tilt table down??
f) Retract tilt table to flat.
g) Close chomper.
Update:  I should have noted that tilt-out deployment in general is weird.  Not impossible, but not nearly as straightforward as axial deployment.

3) It's a payload integration nightmare.  Operators have to climb around in a mid-bay cleanroom, doing their post-PAF integration tests.  If anything is weird, they have to climb into the Starship, without disturbing anybody else's rideshares, to fix whatever is wrong.  If they have to de-mount the payload, that's an incredible hazard for rideshares.

SpaceX could provide some kind of multi-PAF platform to use for integration, encapsulate the whole thing in some kind of ISO 8-compliant environment, then slide the whole thing onto the tilt table and lock it down.  But operators are still going to need to perform post-mounting integration tests, and everything is terrible if any of those tests show a problem.

There's a lot to said for the old-timey "encapsulate in the processing facility and bolt the nose on the vehicle" approach.

[meekGee]

What's so hard about a large door / chomper?

1) Unlike Pez, where the launch stresses can be routed around the Pez door, the chomper door has to be load bearing, then still open (and close!) after bearing the load.

2) Spin-stabilized deployment is really, really weird:
a) Open chomper.
b) Tilt payload out.
c) Spin tilt table up??
d) Deploy bird without hitting anything.
e) Spin tilt table down??
f) Retract tilt table to flat.
g) Close chomper.
Update:  I should have noted that tilt-out deployment in general is weird.  Not impossible, but not nearly as straightforward as axial deployment.

3) It's a payload integration nightmare.  Operators have to climb around in a mid-bay cleanroom, doing their post-PAF integration tests.  If anything is weird, they have to climb into the Starship, without disturbing anybody else's rideshares, to fix whatever is wrong.  If they have to de-mount the payload, that's an incredible hazard for rideshares.

SpaceX could provide some kind of multi-PAF platform to use for integration, encapsulate the whole thing in some kind of ISO 8-compliant environment, then slide the whole thing onto the tilt table and lock it down.  But operators are still going to need to perform post-mounting integration tests, and everything is terrible if any of those tests show a problem.

There's a lot to said for the old-timey "encapsulate in the processing facility and bolt the nose on the vehicle" approach.

Of course Pez is simpler, as I agreed above, but only works for constella.

The door itself, you made it more complicated than it has to be, and you're mixing door problems with the inevitable problems of singular super large payloads.

Regarding the Pez door, it cuts almost 180 degrees into the wall.  I don't think any stress is "routed around it" (if I understand that phrase like you meant it). I think When the door is clamped shut, it is structural, like many other doors.  The key is that opening and closing happens when not under load.

The chomper can be very similar.  First of all, don't chomp like a James Bond cartoon rocket. Keep the nose intact, and have the door span only 150 degrees.  Small aperture loss, but lots of simplicity gained.

Spin stabilizes launch - yes, complex, but who ordered that?  Guide rails on the way out, straight line deployment, simple.

[JayWee]

What's so hard about a large door / chomper?

1) Unlike Pez, where the launch stresses can be routed around the Pez door, the chomper door has to be load bearing, then still open (and close!) after bearing the load.

2) Spin-stabilized deployment is really, really weird:
a) Open chomper.
b) Tilt payload out.
c) Spin tilt table up??
d) Deploy bird without hitting anything.
e) Spin tilt table down??
f) Retract tilt table to flat.
g) Close chomper.
Update:  I should have noted that tilt-out deployment in general is weird.  Not impossible, but not nearly as straightforward as axial deployment.

Do you have to spin? Can't you:
a) kill rotation
b) open door
c) detach payload
d) thrust the whole ship "down" using RCS
e) close door

[TheRadicalModerate]

Do you have to spin?

If you want to support spin-stabilized payloads, you need to spin them up somehow.  There's a decent argument to be made that spin-stabilized payloads are now much less common, and tend to be smaller (they may not be able to afford the mass of CMGs or hefty RCS budgets), so maybe using something other than Starship is a possibility.

Can't you:
a) kill rotation
b) open door
c) detach payload
d) thrust the whole ship "down" using RCS
e) close door

If you're just doing ordinary deployments (no spin), then you can presumably open the chomper, tilt the tilt table out, then use a traditional deployment tech.  Not sure I'd want to use a clamp band partially inside a reusable rocket, though.  Kinda hard to control where the band is going to wind up, and in what condition.

FWIW, I think by far the biggest problem with the chomper is that it's a huge pain for payload integration, while a jettisonable fairing (which requires an expendable) is much better understood.  Obviously more expensive, but not ridiculously so.