Starship Payload Bay and Nose Design and Its Impact on Payload Processing

[TheRadicalModerate]

In the Starship Users Guide, we find the following intriguing statement in the "Payload Integration" section:

Payloads are integrated into the Starship fairing vertically in ISO Class 8 (Class 100,000) cleanrooms. Then the integrated payload stack is transferred to the launch pad and lifted onto the Starship vehicle, while maintaining the same vertical orientation throughout the entire process.

Emphasis mine.

This implies that the entire payload bay and nose of the Starship--LOX header tank, canards, and all--comes off, is processed separately from the rest of Starship, and is attached on the pad after the Starship "core" has been stacked on the SuperHeavy.

Am I drawing a proper conclusion from the statement in the SUG?  If not, how do you think payloads will be inserted into the payload bay?

How many versions of this are there?  Do they have common components? 

Are the "chomper" and "hatch" versions the sole deployment mechanisms, or are there more? 

How do you deal with the power connections that need to flow from the batteries and solar cells in the nose to the core?  What about large medium-pressurize lines from the LOX header tank to the core?  How about pressurant lines for the LOX header?  Are there thrusters in the nose that'll need high-pressure GOX and GCH4 lines?

I don't think I've seen much discussion on any of these questions.  Let's discuss!

[steveleach]

I was wondering if the the "payload stack" includes the payload, the adaptor and a "tent" to keep it clean as it is transferred to the pad and loaded into the chomper. Once safely inside chomper the tent can be removed.

If it is a detachable nose, though, would it be that much harder than the SH/SS interstage?

As I understand it we are already assuming SS is fuelled through the SH, and control electronics must also go through that.

[space_snap828]

In the Starship Users Guide, we find the following intriguing statement in the "Payload Integration" section:

Payloads are integrated into the Starship fairing vertically in ISO Class 8 (Class 100,000) cleanrooms. Then the integrated payload stack is transferred to the launch pad and lifted onto the Starship vehicle, while maintaining the same vertical orientation throughout the entire process.

Emphasis mine.

This implies that the entire payload bay and nose of the Starship--LOX header tank, canards, and all--comes off, is processed separately from the rest of Starship, and is attached on the pad after the Starship "core" has been stacked on the SuperHeavy.

Am I drawing a proper conclusion from the statement in the SUG?  If not, how do you think payloads will be inserted into the payload bay?

How many versions of this are there?  Do they have common components? 

Are the "chomper" and "hatch" versions the sole deployment mechanisms, or are there more? 

How do you deal with the power connections that need to flow from the batteries and solar cells in the nose to the core?  What about large medium-pressurize lines from the LOX header tank to the core?  How about pressurant lines for the LOX header?  Are there thrusters in the nose that'll need high-pressure GOX and GCH4 lines?

I don't think I've seen much discussion on any of these questions.  Let's discuss!

It can't be rapidly reusable if they have to disassemble the Starship to put a payload inside. Also you mentioned a variety of technical issues that will come up if it detaches, which I consider a pretty good argument against this solution.
Also that will produce an interesting seam in the heat shield, one they'd have to be very careful about every time they put a payload in.

[starskale]

This implies that the entire payload bay and nose of the Starship--LOX header tank, canards, and all--comes off, is processed separately from the rest of Starship, and is attached on the pad after the Starship "core" has been stacked on the SuperHeavy.

Am I drawing a proper conclusion from the statement in the SUG?  If not, how do you think payloads will be inserted into the payload bay?

That seems highly unlikely and I'm not sure why you are saying it's even implied. Clearly though there is a separable payload component that gets integrated. It's not indicated how much of Starship goes along with that. It seems plausible that the payload door and hinge mechanism is included though.

[dkrening]

If I'm not mistaken, SpaceX also refers to the integrated SH/Starship stack as "Starship".  So the integrated payload fairing may just be the second stage Starship.

[CraigLieb]

What if the starship chopper door is detachable and is integrated with the payload.  It can contain at its base both connections to the ship and connections to the payload. The starship on the pad is essentially open but contains its header tank and control surfaces fuel tanks oxidizer tanks but is not completed till the chomper doors (and payload) are brought to the pad where the hinge of the chomper is connected,  umbilicals connected and then in the final steps chomper door is closed  encapsulating the payload in the starship.

[nacnud]

There are going to be so many starships that I don’t think it’s worth worrying about. They are building prototypes in less than a month and they are only just getting started.

[TheRadicalModerate]

Since I started the thread, I suppose I should make an opening bid.  You'll be shocked--shocked!--to discover that's it's pretty long.


Starship Configurations

Here are the ones that have been enumerated by SpaceX, and I'm going to add one that I think is almost inevitable:

1) The Uncrewed Starship (U-SS), for use launching payloads to some orbit and then landing, with or without down-mass, after payload deployment.  This uses the "chomper" door.  (Note that the pictures in the SUG seem to pre-date addition of the LOX header tank.)

2) The Crewed Starship (C-SS), which launches crew and lands them via EDL, either on Mars or back on Earth.  This uses the "hatch", which appears to be about 3mx3m, and some kind of elevator/crane to deploy cargo to the surface.  Note:  This is not the HLS-compliant thing that was shown a few days ago.  That is...

3) The Crewed Lunar Starship (C-LSS), which boards and unboards crew in some orbit, lands on the Moon, and never returns to Earth via EDL, and therefore has all the EDL gear stripped off of it.  The LSS also uses the hatch and crane/elevator.  It's also the only version we know of so far that uses the large mid-body thrusters for final lunar landing.  I'm making the assumption that the non-crew payload requirements of the LSS are fairly modest.

To this list, I'd like to add a likely fourth configuration:

4) A Uncrewed Lunar Starship (U-LSS), that has all of the EDL gear, but also has the landing thrusters (they'll need to be heat-shielded for EDL), which can launch from Earth and land heavy cargo on the Moon, deploy it, and return to Earth.  I strongly suspect that this needs something more than the 3x3 hatch, but the chomper is clearly wrong for deploying stuff in even weak vertical gravity.


Nose Components

So, given that I think the whole nose comes off, what's the lego kit of components needed to build all of these?  Here's my list, more or less from the bottom up:

a) A platform, 9m in diameter, containing the structural attachments to the core, the hinged platform on which the PAF (or PAFs) sit, and all the control, power, LOX, and gaseous lines needed.  This will form the platform on which 360º payload integration and access will occur in the clean room.  Common to all four Starship versions above.

b) A half-cylinder, 4.5m radius x 8m high, which contains all the communicating control/power/LOX/gas lines.  Common to all four versions, but EDL versions (U-SS, C-SS, and U-LSS) of this have heat shield on the outside.  The C-LSS version does not.

c) Same as #b, but in the stretched form factor, which is...  12.76m high?  Where did that weird number come from?

d) A... what do we call it?... a truncated half-ogive?  For Starship #1 above, this has most of the canards, but it's otherwise just heat-shielded aeroshell, open on the dorsal side.  It's open at the tip, because there are two different tips.

e) A cargo full ogive.  Same as #d, but no chomper opening.  For the U-LSS.

f) A crew ogive.  It can have canards and heat shield (C-SS) or not (C-LSS).  This is the full-up crew system.  It has hatches to a docking tunnel at the top, and two hatches that lead to one or two...

g) Ladder / "dust room" / airlock components.  This is a pressurized shaft that allows shirtsleeve crew to climb down from the crew module to the main deck (#a), where they have an isolated area to don and doff EVA suits, then go through an airlock to step out onto the unpressurized deck.

g) EDL tip.  This is the header tank, the leading edge of the canard, and a whole bunch of heat shielding.  Used for the U-SS, C-SS, and C-LSS.

h) Docking tip.  Instead of header tank, this has a crew access tunnel between the crew ogive and a IDSS-compliant docking port in the nose.  It's used for getting crew onto and off of that C-LSS.  I suspect that it has a fairing to cover the port during launch.

j) Standard chomper fairing.  This covers 180º of the dorsal side of the U-SS.  It has a hinge that attaches to the platform (#b), and latches that secure it to the half-cylinder (#b), half-ogive (#d), and EDL tip (#g).  Note that the chomper doesn't need to hold pressure.

k) Stretched chomper fairing.  Same as #i, but stretched to go with the stretched half-cylinder (#c).

m) Dorsal non-chomper with 9x9 hatch.  Used for C-LSS and U-LSS instead of the chomper.

n) Extra cargo decks/PAFs/flanges.  There's a lot of stuff in this grab-bag, but SpaceX will need the ability to do vertically-stacked co-manifests as well as multiple horizontally distributed PAFs on the U-SS.  On C-SS and C-LSS versions, multiple levels of cargo probably imply a deck with a central hole and hoist, so things on upper decks can be lowered to the main deck level to go out the hatch.  I also haven't given up on my "StarKist" idea, where you have tuna-can-shaped additional crew modules that can slide into the unpressurized parts of the payload bay, and hook up to the crew ogive to handle larger crews or give them more space for long-duration trips.


Payload Processing and Stacking

This is... complicated.  You can make things a lot simpler if you weld a lot of this stuff together, but then encapsulating long payloads requires at least 22m of headroom in the payload processing bay(s), and steady nerves as you lower the tip/ogive/cylinder assemblies over the payload.  I'm going to assume that this is the case, but leave open the possibility that it might be more space-efficient to assemble them around the payload, rather than lowering them on to it.

In all cases, we start with the platform (#a).  We get attach whatever PAFS or human-friendly decking we need to it, and then lower the payload(s) into place.  Crews have open access to the payloads for checkout, fueling, and other integration operations.

If we're building a C-LSS, we next mount the ladder/dustroom/airlock components onto the platform.  Since NASA was jazzed about having two airlocks, I guess that there are probably two of these.

Now we're ready lower the complicated stuff over the payload.  There are different configurations for the different types of Starships:

1) U-SS:

EDL tip on top of half-ogive.
Half-ogive on top of half-cylinder.
Half-cylinder (with heat shield) latches onto main platform.

If we need to install decking or extra layers of PAFs, now is the time.  Presumably, payloads for extra layers of PAFs were integrated separately, and their crews are really nervous as they get slid into place.

Finally, we install the chomper, and we're ready to lift the whole thing onto the core Starship.

2) C-SS
EDL tip on top of crew ogive (with heat shield).
Crew ogive on top of half-cylinder (with heat shield).
Half-cylinder latched into place on platform.
Attach crew ogive to ladder/dustroom/airlocks if needed.
Slide in decking and extra payloads, if needed.
Seal it up with the non-chomper with 3x3 hatch.

3) C-LSS
Docking tip on top of crew ogive.
Crew ogive (unshielded, no canards) on top of half-cylinder.
Attach access tunnel to crew ogive upper hatch.
Half-cylinder (unshielded) latched onto platform.
Attach ladder/dustroom/airlocks to crew ogive lower hatches.
Slide in decking and extra payloads.
Seal it up with the non-chomper with 3x3 hatch.

4) U-LSS
EDL tip on top of half-ogive.
Half-ogive on top of half-cylinder (shielded).
Latch half-cylinder onto platform.
Slide in extra decks and payloads.
Seal it up with the non-chomper with 3x3 hatch.

Final Notes and Weasel Words

Note that I've arranged this so that when SpaceX comes to its senses, it can replace the non-chomper with a pair of payload bay doors, and now there's a way to deploy 8m-diameter payloads straight onto the surface.

I really don't believe that the C-SS is a real thing.  With the canards on the half-ogive, even if you wanted to put in launch abort engines to blow it clear, you'd have to lift the LOX header tank, and I can't think of a way to make something aerodynamically stable with the canards on.  So it's scary as hell launching in this thing.  The only thing scarier is doing EDL in it.  I fully expect that crewed Starship missions begin and end in LEO or NRHO, where crews arrive/depart either on a D2 or Orion, respectively.

Finally, one last thing:  For a C-LSS used in the HLS architecture, you have to get surface payloads transferred from the logistics U-SS to the C-LSS in NRHO.  This is hard if you're lobbing stuff through a pair of 3x3 hatches.  It's considerably easier if you transfer tail pods during refueling.  But if there's a requirement for hatch-based payload on crewed surface missions, this needs some serious thinking through.

[TheRadicalModerate]

It can't be rapidly reusable if they have to disassemble the Starship to put a payload inside. Also you mentioned a variety of technical issues that will come up if it detaches, which I consider a pretty good argument against this solution.
Also that will produce an interesting seam in the heat shield, one they'd have to be very careful about every time they put a payload in.

Stacking the nose on the Starship is probably less difficult than stacking the Starship on the SH.  Your latching mechanism is probably a lot beefier, because it has to withstand the stress of EDL, but I don't think that makes it operationally any more complex.

The heat shield issue is important.

[dglow]

IMO the only reasonable interpretation is that they're referring to vertically loading payload into chomper. The 'integrated payload stack' is just that: payload, not spacecraft. I'll bet dollars to doughnuts that the top of Starship, for all planned variants, remains intact and attached.

[su27k]

Just a reminder: This is how currently Falcon 9 fairing encapsulation works. Payload sits on top of PAF, vertically, then both fairing halfs close around the payload, vertically. Then the whole thing is transported to the HIF, vertically.

Falcon 9 fairing is 13 meters tall and 5.2 meters wide, if they build the extended fairing for USAF, then it will be over 20 meters tall. The Starship fairing section is 23 meters tall and 9 meters wide.

Falcon 9 fairing is not just some inert shell, it has clamps that needs to lock during ascend and then unlock during fairing separation, presumably driven by pneumatics. The recovery version has cold gas thrusters and parachutes, presumably with their own avionics. The top of the fairing also have a patch which was believed to be TPS, which is split between two halfs. The integrated fairing/payload stack also have some electrical connection with 2nd stage for payload separation command and the data connection between payload and customer GSE when on the launch pad. And of course the integrated fairing/payload stack needs to be securely mated to the top of 2nd stage and need to endure the load during launch.

Given all these, is it too hard to believe they could do something similar to a separate detached Starship fairing section?

[dante2308]

It can't be rapidly reusable if they have to disassemble the Starship to put a payload inside. Also you mentioned a variety of technical issues that will come up if it detaches, which I consider a pretty good argument against this solution.
Also that will produce an interesting seam in the heat shield, one they'd have to be very careful about every time they put a payload in.

My take is that the slowest step in the launch flow will ultimately be payload integration so having a detachable payload section allows payloads to be processed in parallel rather than between flights. Then you just plop a completely integrated payload and adapter on the fuel tanks. I think trying to move Starship off the pad and into a clean room for payload integration would be a much slower process than detaching/attaching noses. You're right that they need to fit together seamlessly for it all to work, but interestingly, whether or not Starship survives re-entry is of no concern of most commercial payloads.

[TheRadicalModerate]

IMO the only reasonable interpretation is that they're referring to vertically loading payload into chomper. The 'integrated payload stack' is just that: payload, not spacecraft. I'll bet dollars to doughnuts that the top of Starship, for all planned variants, remains intact and attached.

The problem is that you can't load payload vertically into the chomper.  To load it vertically, you have to take off the tip with the header tanks, and the chomper would have to encompass much more that 180º of the circumference of the Starship.

In short, you have to take most of the nose off if you're lowering the payload in vertically.  That's the realization that made me spin up this thread.

They could load a payload into the bay by rotating it to 45º or whatever the tilting PAF allows, then slowly translating it along a diagonal path until it makes contact with the PAF, attaching it to the PAF, and then assisting as the PAF got rotated back to vertical--but that's insane.  Not only is it insane but it's also not the definition of "maintaining vertical integration throughout the entire process".

[TheRadicalModerate]

Just a reminder: This is how currently Falcon 9 fairing encapsulation works. Payload sits on top of PAF, vertically, then both fairing halfs close around the payload, vertically. Then the whole thing is transported to the HIF, vertically.

Falcon 9 fairing is 13 meters tall and 5.2 meters wide, if they build the extended fairing for USAF, then it will be over 20 meters tall. The Starship fairing section is 23 meters tall and 9 meters wide.

Falcon 9 fairing is not just some inert shell, it has clamps that needs to lock during ascend and then unlock during fairing separation, presumably driven by pneumatics. The recovery version has cold gas thrusters and parachutes, presumably with their own avionics. The top of the fairing also have a patch which was believed to be TPS, which is split between two halfs. The integrated fairing/payload stack also have some electrical connection with 2nd stage for payload separation command and the data connection between payload and customer GSE when on the launch pad. And of course the integrated fairing/payload stack needs to be securely mated to the top of 2nd stage and need to endure the load during launch.

Given all these, is it too hard to believe they could do something similar to a separate detached Starship fairing section?

Yes, this was my thinking as well.  However, let's not push the analogy too far.  The F9 PLF never has to withstand the stresses and heating that a high angle of attack at reentry speeds will put on it.  This isn't an easy engineering problem.  But it's the only way I can see vertical integration actually working, and they've been crystal clear that this is vertical payload processing architecture.

[r8ix]

Lower chomper door past 90° (or remove it completely), slide payload in (vertical orientation, horizontal motion), close/ reattach chomper door…

[starskale]

IMO the only reasonable interpretation is that they're referring to vertically loading payload into chomper. The 'integrated payload stack' is just that: payload, not spacecraft. I'll bet dollars to doughnuts that the top of Starship, for all planned variants, remains intact and attached.

The problem is that you can't load payload vertically into the chomper.  To load it vertically, you have to take off the tip with the header tanks, and the chomper would have to encompass much more that 180º of the circumference of the Starship.

In short, you have to take most of the nose off if you're lowering the payload in vertically.  That's the realization that made me spin up this thread.

They could load a payload into the bay by rotating it to 45º or whatever the tilting PAF allows, then slowly translating it along a diagonal path until it makes contact with the PAF, attaching it to the PAF, and then assisting as the PAF got rotated back to vertical--but that's insane.  Not only is it insane but it's also not the definition of "maintaining vertical integration throughout the entire process".

As mentioned above, imagine if the hinge mechanism and door is part of the integrated payload section. In such a case, the  section can be moved horizontally out of the Starship, getting clear of the header tank, then be lifted vertically. And the reverse process for insertion. As described in the document, this section would always remain vertical. Any necessary payload umbilicals could be integrated into the payload door and remain connected during the entire process.

Removing forward sections of Starship means disconnecting several lox/pressurization lines for the header tank, the electrical connections for the canards, making a split in the heatshield, making a structural break between the forward and aft aerodynamic supports of starship, disconnecting RCS fuel lines, oxidizer lines, and controls, disconnecting sensors, etc, etc. It's just not a desirable thing.

Additionally, the more pieces of Starship come along for the ride, the harder any clean room will be.

edit: r8ix has a similar idea above, but in that case just removing the payload door completely. I actually like that idea a bit more because it allows access to attachment points for lifting. Of course, you'd still need an interior door to maintain the clean environment.

[TheRadicalModerate]

Also that will produce an interesting seam in the heat shield, one they'd have to be very careful about every time they put a payload in.

A thought on the heat shield seam problem:  Unlike a regular fairing, this never has to be jettisioned after launch.  Unlike the SH-to-SS interstage, there's not need for a reliable release mechanism.  SpaceX has to be able to stack the nose quickly and reliably onto the top of the Starship tanks, and unstack it after a missions, but the interstage mechanism can have as many attachment points and overlapping flanges as needed to ensure the proper thermal and mechanical behavior.

[TheRadicalModerate]

Lower chomper door past 90° (or remove it completely), slide payload in (vertical orientation, horizontal motion), close/ reattach chomper door…

I guess that that would work in a payload processing facility, although you have no access to the back of the payload after mounting it.  But, per the SUG, they're talking about transferring stuff to the launch pad and lifting it "onto" (not into) the Starship.  If you're doing this on the launch pad, do you really think you can do all of the necessary mounting and checkout 80 meters up, with the customer's people bumbling around?  Talk about slow launch turnaround times.

And speaking of slow turnaround times:  think about the workflow.  Payload integration is slow, arduous, and exacting, with checkout taking pretty much until the customer is satisfied.  Starship stacking on SuperHeavy, on the other hand, is being designed to be simple and quick.  If you want high launch throughput, simple queuing theory says that you want multiple payloads in the integration pipeline while you're launching the current one.  Decoupling the nose from the tankage and thrust structure, then mounting the nose just before launch, achieves that.

[starskale]

Lower chomper door past 90° (or remove it completely), slide payload in (vertical orientation, horizontal motion), close/ reattach chomper door…

I guess that that would work in a payload processing facility, although you have no access to the back of the payload after mounting it.  But, per the SUG, they're talking about transferring stuff to the launch pad and lifting it "onto" (not into) the Starship.  If you're doing this on the launch pad, do you really think you can do all of the necessary mounting and checkout 80 meters up, with the customer's people bumbling around?  Talk about slow launch turnaround times.

And speaking of slow turnaround times:  think about the workflow.  Payload integration is slow, arduous, and exacting, with checkout taking pretty much until the customer is satisfied.  Starship stacking on SuperHeavy, on the other hand, is being designed to be simple and quick.  If you want high launch throughput, simple queuing theory says that you want multiple payloads in the integration pipeline while you're launching the current one.  Decoupling the nose from the tankage and thrust structure, then mounting the nose just before launch, achieves that.

Seriously? First, onto vs into is mincing words. You're putting way too much value into word choice.

Second, you're worried about the payload mounting and how hard and complicated it might be. But you're somehow not concerned at all about decoupling the top half of Starship from the bottom half? Seriously? You think that will somehow be quicker?

[Lars-J]

IMO the only reasonable interpretation is that they're referring to vertically loading payload into chomper. The 'integrated payload stack' is just that: payload, not spacecraft. I'll bet dollars to doughnuts that the top of Starship, for all planned variants, remains intact and attached.

The problem is that you can't load payload vertically into the chomper.  To load it vertically, you have to take off the tip with the header tanks, and the chomper would have to encompass much more that 180º of the circumference of the Starship.

If you don’t think you can load a payload vertically into the chomped without taking off the nose, then you lack imagination. I can imagine many custom lifting rigs that would make it possible. (From a crane) Or just install it from the side, already vertical. (Like a forklift loading a truck)