Starship Users Guide

[Twark_Main]

2) This "extended payload volume" comment is interesting. I'm guessing that that's for an expendable system without header tanks. I can't imagine that they can stretch the nose with the canards there. I guess that it's possible that they're planning on adding an extra 5 m to the cylindrical section but that's not shown in the renderings.

Expendable seems unlikely, even considering Starship's low (aspirational) build cost. I would bet on just a different weight distribution, or possibly smaller canards.

4) They're sticking with the chomper! I simply don't understand this.

5) I especially don't understand the chomper in light of them offering the F9- and FH-compatible clamp-band payload attach fittings. Seems like you'd wind up with separation debris wandering around in the payload bay.

Just thrust backwards to clear it out.

7) They're advertising 100+ t payload to 500x500x98.9º polar orbits.

They're advertising "up to" those parameters. I presume the math indicates that it can do both at the same time, but the text is ambiguous.

8 ) I'm a bit surprised to see the crew version with windows. I was almost certain that the first crew modules would be essentially payloads integrated into the regular payload bay. I suppose that the crew variants could just be "aspirational", to use one of Elon's favorite words. The point of this document is to drive non-crew payload planning.

And I was just as certain that you were mistaken. Especially given the revelation about swappable payload sections (which offers largely the same advantages), I hope we can finally put that "box in a box" concept into a pine box.

It's not good practice for SpaceX to rely on payload integrators to devise and test that kind of hardware.

Why not?

Furthermore, with the low price per launch, it's not clear if the complexity of co-manifesting can even pay for itself. If the payload integrators can't do it economically, why should SpaceX waste their own money?

11) Note that the surface cargo payload bay is divided into shelves to offload separate modules. I wonder if this is just fanciful or whether there's engineering behind this.

12) It appears that for surface offload, they're using part of the fairing as the elevator platform. That's... interesting. I'll be curious to see how well they do packing it back in place for the return trip. Doesn't seem like a super-reliable plan to take part of your fairing, load it with random stuff, plunk it on the ground, roll stuff off of it, and then reposition it back in place for reentry.

This is an old rendering. The document also says that "various payload bay configurations are available and allow for fully autonomous deployment of cargo to Earth (!), Lunar, or Martian surfaces with one example shown in Figure 7 (ie the image you're referencing)."

[dlapine]

So, maybe I'm misunderstanding something here but, for the GTO with 21tons, can't SpaceX simply replace the 79tons of potential cargo with additional methalox? Yes, the tanks would need to be sized to accommodate a larger fuel/O2 load.

Perhaps the simpler question is what's the dV of Starship in leo with 79 tons of propellant to burn and 21 tons of cargo? Can that make GTO -1800m/s?

<edited for spelling>

[Ludus]

Starship will get a small boost for GTO payloads when launching from Boca Chica vs the Cape (28.6d vs 26.0d), about 65-70m/s.

Not a huge boost, but enough to theoretically add ~3 tonnes to the GTO-1800 payload vs the cape.

What does it get from the equator?

[OTV Booster]

Many of us have been working on space station designs, and no doubt all of us have been wondering how large of payloads we could fit inside of a Starship. Now we know, and I marked up the diagram in the Users Guide to make it easier to see what size cylindrical modules could fit.

As a note, for some of my rotating space station designs, I had been hoping for a minimum of 8m in diameter by 10m in length, but I can get by with 7m in diameter and 10m in length if it means transportation costs are significantly less.

The XL version will get you 8x12.76

[OTV Booster]

My initial thoughts:

5) I especially don't understand the chomper in light of them offering the F9- and FH-compatible clamp-band payload attach fittings. Seems like you'd wind up with separation debris wandering around in the payload bay. Also, how does a system designed to move payload axially away from the vehicle suddenly wind up lifting them out to avoid the fixed clamshell at the bottom of the bay?

Based on the deployment render, I think the PAF must be hinged to angle the payload prior to deployment.

After a second read, that's what I think as well.

Anybody know about what kinds of separation debris you get coming off of a clamp-band PAF?

None if you do it right

[Cheapchips]

The document also says that "various payload bay configurations are available and allow for fully autonomous deployment of cargo to Earth (!)..."

There's also this on the following page

The cargo version can also be used for rapid point-to-point Earth transport.

I don't think we've had cargo P2P specifically mentioned by SpaceX before, although it has been speculated on NSF as a P2P starter business.

[TheRadicalModerate]

My initial thoughts:

8\) I'm a bit surprised to see the crew version with windows. I was almost certain that the first crew modules would be essentially payloads integrated into the regular payload bay. I suppose that the crew variants could just be "aspirational", to use one of Elon's favorite words. The point of this document is to drive non-crew payload planning.

I don't think windows are optional for dear moon considering the goal is a pleasure cruise around the moon for a rich patron and some artists. I suppose technically this could be done with a windowed vessel inside a chomper and have the chomper open, but that sounds like a big mass penalty for not much benefit.

Windows on the module with the chomper open was exactly what I've been thinking.

I'm extremely skeptical that you can have that many windows withstanding the aero and thermal loads of launch, to say nothing of EDL.  It's a lot easier if the windows are inside a fairing, i.e., the chomper.

Update:  Is it a big mass penalty?  As a cargo system, the Starship payload bay doesn't have to be a pressure vessel.  ISTM that integrating a pressure vessel directly into the structure vs. just sliding it onto a PAF or trunnion are pretty close in overall mass.

[Coastal Ron]

I don't think we've had cargo P2P specifically mentioned by SpaceX before, although it has been speculated on NSF as a P2P starter business.

SpaceX has talked about point-to-point for many years, and though they show the passenger version in their for it, I don't think they have ever ruled out cargo P2P.

[equiserre]

2) This "extended payload volume" comment is interesting. I'm guessing that that's for an expendable system without header tanks. I can't imagine that they can stretch the nose with the canards there. I guess that it's possible that they're planning on adding an extra 5 m to the cylindrical section but that's not shown in the renderings.

Expendable seems unlikely, even considering Starship's low (aspirational) build cost. I would bet on just a different weight distribution, or possibly smaller canards.

or, move the bulkheads back to give you 5m bigger payload bay. You end up with a 900t propellant starship which can still launch 50t to LEO. 50t/22m lenght payload anyone?

[Keldor]

My initial thoughts:

8\) I'm a bit surprised to see the crew version with windows. I was almost certain that the first crew modules would be essentially payloads integrated into the regular payload bay. I suppose that the crew variants could just be "aspirational", to use one of Elon's favorite words. The point of this document is to drive non-crew payload planning.

I don't think windows are optional for dear moon considering the goal is a pleasure cruise around the moon for a rich patron and some artists. I suppose technically this could be done with a windowed vessel inside a chomper and have the chomper open, but that sounds like a big mass penalty for not much benefit.

Windows on the module with the chomper open was exactly what I've been thinking.

I'm extremely skeptical that you can have that many windows withstanding the aero and thermal loads of launch, to say nothing of EDL.  It's a lot easier if the windows are inside a fairing, i.e., the chomper.

Update:  Is it a big mass penalty?  As a cargo system, the Starship payload bay doesn't have to be a pressure vessel.  ISTM that integrating a pressure vessel directly into the structure vs. just sliding it onto a PAF or trunnion are pretty close in overall mass.

I mean, if you can have one window, you can have many.  It's just a matter of mass penalty since they're quite a bit heavier than plain siding.  (Anyone have numbers for this?  Have materials improved since the Shuttle?)

Obviously you'd need to make sure to keep them sheltered from the worst of reentry, so maybe they'd want to push the edge of the big window section back from the nose tip a little bit, but otherwise the locations seem to make sense to me.  But SpaceX has excellent modeling software.  They'll be able to figure out what works and what doesn't work.

[Keldor]

The document also says that "various payload bay configurations are available and allow for fully autonomous deployment of cargo to Earth (!)..."

There's also this on the following page

The cargo version can also be used for rapid point-to-point Earth transport.

I don't think we've had cargo P2P specifically mentioned by SpaceX before, although it has been speculated on NSF as a P2P starter business.

I mean, if you can have P2P passengers, you can have P2P cargo, assuming you have anyone interested in using it.  If they can, say, shave 8 hours off a trans-Pacific shipment, it could be a big win for some critical part in a factory that has the place shut down hard and loosing $1000s per hour, even if it doubles shipping costs.

But autonomous unloading is useful for passengers too.  Imagine them starting unloading the luggage section while the flight personel are still rushing over from outside the exclusion radius immediately after landing.  Could save 15 minutes on the turnaround from this alone!  Significant savings when you're trying to reach airline type turnarounds.

A really big win might be possible if they can load up the entire passenger module on the ground like they're proposing for satellite launches.  Board the passengers into the module while they're still on the boat going out to the launch platform, and then all they have to do on the pad is raise the module up and mount it into the vehicle.  And the reverse when disembarking.  There are, of course, a lot of GSE concerns to this approach, such as making sure the fiery liftoff doesn't damage the lift tower, but it might be feasible.  Some sort of mobile lift tower might be possible, which could roll a safe distance away during launch and landing, and would have the added benefit of accomodating the vehicle landing a meter or two off target without having to pick it up and reposition it for loading/unloading.

[Robotbeat]

> 21ton to GTO

That's somewhat unexpected. I remember claims that GTO payload was zero without a separate third stage.

It can't go direct to GEO without refueling, but GTO is another story.  I get almost exactly 21 t to GTO in my model (which is a first; it's hardly ever that accurate).  Note that the GTO that they're specifying is GEO-1800 m/s.

Maybe it can do direct to GEO fully reusably by using a modified Dragon XL as a Chomper-recoverable third stage:

Separate topic: Dragon XL (without the pressure vessel, with some body-mounted panels and stretched tanks) would make a good recoverable third stage for Starship.

Would allow Starship to do single-launch fully recoverable launches to direct GSO.

The Dragon XL with the payload on top would stage at GTO out of Starship, do the burn into GSO, separate payload, then go back to GTO (phasing may take time?), and dock with Starship/Chomper and come back to Earth. Full reuse, single-launch direct to GSO. Could probably do escape missions this way, too.

Likewise, this is how Dragon XL could be launched and recovered from Starship for Gateway missions. Those folding solar panels (necessary for independent power on Gateway—body panels aren’t enough) will need to be either foldable or expended.

[Ludus]

21t to GSO on a launcher that’s fully reusable, returns to launch site, needs no extra in orbit propellant, would make putting really big satellites into GSO cheap and easy. They could be 5 or 6X the size. Much bigger solar arrays and antennas would mean comparably smaller cheaper ground antennas. Global demand for HDTV isn’t going away despite streaming. If nobody else is doing next generation GSO satellites maybe SpaceX will do them itself.

[tbellman]

Update:  Is it a big mass penalty?  As a cargo system, the Starship payload bay doesn't have to be a pressure vessel.  ISTM that integrating a pressure vessel directly into the structure vs. just sliding it onto a PAF or trunnion are pretty close in overall mass.

On the other hand, the cargo hold not being pressurized during entry and descent, means that it needs additional reenforcements to provide stiffness, stability, and buckling resistance.  Integrating the crew pressure vessel with the outer shell means that the one bar pressure inside helps with that stiffness.  Having a separate pressure vessel inside the normal cargo hold, you get the mass penalties of both.  I don't dare make estimates as to how large those mass penalties are, though.

Except for the possible weaknesses of windows, I don't see any advantages to doing the crew compartment as a separate cargo payload.  I can't imagine there would be much, or any, savings of development or manufacturing costs.

There are some things that having a separate crew compartment inside a chomper makes more difficult as well.  E.g, egress and ingress on the surface of Mars and the Moon, or docking to space stations like ISS or the Lunar TollboothGateway.  An open chomper clamshell would be in the way, or at the very least severely constrain where you can dock.  Even if Starship would only need those capabilities later on, making a separate crew compartment as a cargo module initially, would be a detour on the way to what SpaceX really want to achieve.

[niwax]

Update:  Is it a big mass penalty?  As a cargo system, the Starship payload bay doesn't have to be a pressure vessel.  ISTM that integrating a pressure vessel directly into the structure vs. just sliding it onto a PAF or trunnion are pretty close in overall mass.

On the other hand, the cargo hold not being pressurized during entry and descent, means that it needs additional reenforcements to provide stiffness, stability, and buckling resistance.  Integrating the crew pressure vessel with the outer shell means that the one bar pressure inside helps with that stiffness.  Having a separate pressure vessel inside the normal cargo hold, you get the mass penalties of both.  I don't dare make estimates as to how large those mass penalties are, though.

Except for the possible weaknesses of windows, I don't see any advantages to doing the crew compartment as a separate cargo payload.  I can't imagine there would be much, or any, savings of development or manufacturing costs.

There are some things that having a separate crew compartment inside a chomper makes more difficult as well.  E.g, egress and ingress on the surface of Mars and the Moon, or docking to space stations like ISS or the Lunar TollboothGateway.  An open chomper clamshell would be in the way, or at the very least severely constrain where you can dock.  Even if Starship would only need those capabilities later on, making a separate crew compartment as a cargo module initially, would be a detour on the way to what SpaceX really want to achieve.

An idea I've been playing around with for a bit is commonality with the cargo version as you say, but also replacing the chomper door with a different insert that contains the windows and airlocks. The door is a seperate component anyway and shouldn't be much harder to replace than the cargo itself.

[mclumber1]

For the crewed version, I wonder if they could simply remove the chomper portion of the starship and replace it with a crew module (with windows).  This module would be self contained and theoretically be capable of sustaining a crew without the starship.

[soyuzu]

...and it's logical anyways for 100 tons LEO launch vehicle to be able to launch that amount to GTO...

Why is that logical? What Isp and dry mass are you assuming? I'm getting only ~1700m/s delta-v from LEO assuming 120mT dry mass and 3750 m/s Isp.

I get the same results. 100t to LEO is possible even with a 120t starship. Now 21t to GTO I can´t get it even with an 80t starship.
what is the delta V to a direct GTO as described?

Please note the LEO payload is actually

Up to 500-km circular orbit at up to 98.9-deg inclination

No problem with that. What I dont understand is the GTO 21t. Anybody know the delta v required for that GTO?

High inclination, high altitude LEO requires more delta-v, so the payload to 28.5 degree 100nm LEO can actually be significantly higher. 500km SSO requires some 500-600m/s more delta-v, which can translate to 40t more payload to minimum LEO like GTO Parking orbits.

[ZachF]

21t to GSO on a launcher that’s fully reusable, returns to launch site, needs no extra in orbit propellant, would make putting really big satellites into GSO cheap and easy. They could be 5 or 6X the size. Much bigger solar arrays and antennas would mean comparably smaller cheaper ground antennas. Global demand for HDTV isn’t going away despite streaming. If nobody else is doing next generation GSO satellites maybe SpaceX will do them itself.

Or you could even throw up 10x 2-tonne all-electric sats if you build them flat and stackable like Starlink.

[niwax]

SpaceX has already partnered with Momentus on their LEO rideshares. It's not hard to see how they could offer GTO rideshares with GEO and lunar options through a COTS third stage.

[TorenAltair]

21t to GSO on a launcher that’s fully reusable, returns to launch site, needs no extra in orbit propellant, would make putting really big satellites into GSO cheap and easy. They could be 5 or 6X the size. Much bigger solar arrays and antennas would mean comparably smaller cheaper ground antennas. Global demand for HDTV isn’t going away despite streaming. If nobody else is doing next generation GSO satellites maybe SpaceX will do them itself.

Or you could even throw up 10x 2-tonne all-electric sats if you build them flat and stackable like Starlink.

Imo it would be better to change the sat design itself. Instead of using the best of the best components, go down 2 steps in capability (for example solar array efficiency) and make the sats cost only a fraction of today‘s expensive sats. Of course they would weigh then perhaps the double, but with cheap transportation, it could reduce the cost of space „stuff“ significantly. No longer the need to go for ultra lightweight with expensive components and manufacturing. That‘s the real benefit imo of (if successful) Starship and perhaps New Glenn.