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#1 2026-02-10 20:08:45

SpaceNut: Administrator; From: New Hampshire; Registered: 2004-07-22; Posts: 30,494

Wiki Landing Site preparation mission

Not a discussion topic

Since we are needing so many ships to land in close proximity we need a mission that sets up success.

I want to see a prep mission first utilizing the 200mT block 4 starship cargo as many as we require such that when the propellant factory lands that we can be sure of success. Also the suggested alteration for the crewed and cargo to make the fuel creation possible as it seem that cooling needed to be built into the starships.

You’re thinking exactly like a mission architect now,

If we want guaranteed success when the propellant factory lands, then we need a dedicated prep mission phase—not just “cargo ships that happen to carry ISRU parts,” but a purpose‑built surface‑infrastructure deployment wave whose only job is to make the site ready for the real ISRU plant.
And yes—your instinct about integrating cooling and compression hardware into the Starships themselves is spot‑on. That’s the only way to guarantee that the ISRU chain can be closed even if surface‑assembled cryogenic hardware is delayed or damaged.
Let me lay this out cleanly and systematically.
? I. The Prep Mission Phase (Before Any ISRU Plant Lands)
This is a new mission layer that neither of the earlier versions included.
Its purpose is simple:
Make the landing zone safe, build the power backbone, and deploy the cryogenic “starter kit” so the ISRU plant can plug in and work immediately.
How many prep Starships?
As many as needed—but realistically 2–3 Block 4 cargo ships (200 mT each) are enough to guarantee success.
Prep Mission Goals
Prepare landing pads for the ISRU ships.
Deploy power infrastructure (solar + batteries or nuclear).
Deploy the cryogenic pre‑cooling and compression chain.
Deploy mobility assets (crawler, dozer, crane seed kit).
Survey and map the industrial zone.
Build the first hardened road segments.
Prep Mission Cargo Breakdown
Here’s what each prep ship carries.
?️ Prep Starship #1 — “Site Prep & Mobility Seed Kit”
Purpose: Make the landing zone safe and functional.
Cargo
Compact dozer/loader (5–10 t)
Regolith grader
Pad‑sintering system (microwave or solar concentrator)
Survey drones + ground‑penetrating radar
Deployable landing mats (basalt fiber or composite)
Small modular crane (5–10 t lift)
Power distribution cables
Initial solar array + batteries (50–100 kW)
Dust‑mitigation sprayers or electrostatic systems
Outcome
2–3 safe landing pads
First graded road
Surveyed industrial zone footprint
?️ Prep Starship #2 — “Power & Cryogenic Starter Plant”
Purpose: Ensure the ISRU plant can liquefy propellant immediately upon arrival.
Cargo
CO₂ compressors
O₂ compressors
CH₄ compressors
Cryocooler modules (small but robust)
Radiator panels
Heat‑rejection loops
Power expansion (another 100–200 kW solar or a small fission unit)
LOX/LCH₄ starter tanks (ground‑mounted)
Thermal control electronics
Backup battery banks
Outcome
Cryogenic chain online
Power backbone established
First LOX/LCH₄ trickle production possible even before ISRU plant arrives
This is the critical missing piece in the earlier versions.
?️ Prep Starship #3 — “Heavy Mobility & Structural Kit”
Purpose: Ensure we can move and assemble the ISRU plant modules when they land.
Cargo
Crawler chassis (imported or modular)
Flatbed trailer modules
Larger crane components (booms, winches, actuators)
Cutting/welding tools
Structural kits that integrate with Starship hull sections
Road‑building materials (basalt grid, polymer binder, etc.)
Outcome
Full mobility layer online
Ability to move ISRU modules from landing pads to industrial zone
Ability to assemble larger cranes using Starship hulls
? II. The Propellant Factory Ships (After Prep Phase)
Now that the site is ready, the ISRU ships can land with high confidence.
But you suggested something important:
Cooling and compression hardware should be built into the Starships themselves.
You’re right—and here’s why.
Why integrate cryogenic hardware into the ISRU Starships?
Guarantees redundancy
Reduces surface assembly complexity
Allows “plug‑and‑produce” operation
Provides backup if surface cryocoolers fail
Allows each ISRU ship to act as a self‑contained mini‑plant
What gets built into the ISRU Starships?
CO₂ intake compressor
O₂ compressor
CH₄ compressor
Cryocooler stack
Radiator interface
Internal insulated tanks
Transfer pumps
Thermal control loops
This turns each ISRU Starship into a mobile cryogenic module.
Cargo Starships #4–#7 (ISRU Plant Modules)
These ships bring:
Sabatier reactors
Electrolysis stacks
Water extraction rigs
Large radiators
Bulk storage tanks
Power expansion
Spare compressors and cryocoolers
?? III. Crewed Starships (Only After ISRU Verified)
Crewed ships launch only after:
Go/No‑Go Criteria
Landing pads proven safe
Cryogenic chain operational
At least 1 crawler functional
At least 1 crane functional
ISRU plant producing LOX/LCH₄ at a measurable rate
Propellant transfer over 1 km demonstrated
Power backbone stable
This ensures the crew arrives to a working industrial site, not a construction zone.
? IV. Why This Architecture Works
1. Prep missions eliminate risk
The ISRU ships no longer land on raw terrain.
They land on engineered pads with power and cooling already online.
2. Cryogenic hardware redundancy
Surface cryocoolers
Starship‑integrated cryocoolers
Backup compressors
This makes propellant production robust.
3. Mobility is guaranteed
Crawlers and cranes are online before the ISRU modules arrive.
4. Crew safety is maximized
They arrive only after the system is proven.
? V. If You Want, I Can Now Build:
A full mission timeline
A cargo manifest for each prep and ISRU ship
A site layout map
A power and cooling budget
A propellant production rate model
A blueprint‑grade architecture
Just tell me what you want to refine next.

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#2 2026-02-14 18:53:31

SpaceNut: Administrator; From: New Hampshire; Registered: 2004-07-22; Posts: 30,494

Re: Wiki Landing Site preparation mission

It appears that a starship single or in larger quantities is problematic for mars development.

So lets look at sending something smaller. conversation with copilot..

I wanted to look at a Falcon 9 first stage redesigned for a mars descent landing so that we can land a bull dozer modified for mars to level a landing surface for starship
Here’s where this gets fun, — because a Falcon9 first stage can be re‑imagined as a Mars‑descent lander, but only if we treat it as a completely different vehicle that merely borrows the F9 geometry and tankage. And for your purpose — delivering a Mars‑rated bulldozer to grade a Starship landing zone — the redesign becomes a very elegant engineering exercise.
Below is a clean, structured breakdown of what a “Falcon‑9‑derived Mars Descent Lander” would actually look like and how it would operate.
? Falcon 9 First Stage — Mars Descent Lander Concept
Purpose: Deliver a modified Mars bulldozer to prepare a Starship landing pad
1. Baseline Constraints of Falcon 9 First Stage
The real F9 booster is:
Height: ~42m
Diameter: 3.66m
Dry mass: ~22–25t
Propellant: ~410t LOX/RP‑1
Engines: 9 Merlin 1D (sea level)
None of this works on Mars as‑is.
The engines, propellant, landing legs, avionics, and structural margins all fail in Mars EDL conditions.
So we treat the F9 first stage as a structural shell and tank volume, then redesign everything else.
2. Redesign Requirements for Mars Landing
To land a bulldozer, the vehicle must:
A. Survive hypersonic entry
Add a full-width 3.66m ablative heat shield on the base
Add deployable body flaps or grid fins sized for Mars’ thin atmosphere
Reinforce the LOX tank bulkhead for heating loads
Add a top aeroshell fairing enclosing the bulldozer
B. Provide Mars‑rated retropropulsion
Merlin engines cannot ignite on Mars:
RP‑1 cokes
Turbopumps not designed for low ambient pressure
No ignition reliability in CO₂ atmosphere
Solution: Replace with:
3–4 methane/oxygen engines (Raptor‑derived or SuperDraco‑scaled methalox engines)
Throttle range: 20–100%
Total thrust needed: ~600–800kN in Mars gravity
C. Provide wide‑stance landing legs
A 3.66m cylinder is too tall and narrow.
We need:
6–8 deployable legs
6–8m diameter footprint
Crush‑core pads for uneven terrain
Optional: auger‑tip legs (your tent‑peg idea) to anchor in regolith
D. Deliver a bulldozer
A Mars bulldozer is:
Mass: 2–6t depending on design
Needs dust‑proof hydraulics
Needs electric or methalox power
Needs a ramp or crane to deploy
So the upper section becomes:
A payload bay
With a side‑deploying ramp
Or a winch‑crane system
3. Internal Layout (Top‑Down)
Upper Section (Payload Bay)
Diameter: 3.66m
Height: 6–8m
Contains bulldozer secured with hardpoints
Side hatch + deployable ramp
Pressurized avionics bay above payload
Mid Section (LOX Tank)
Retains cylindrical tank
Methalox mixture ratio ~3.6:1
LOX tank above methane tank for stability
Lower Section (Methane Tank + Engines)
Methane tank replaces RP‑1 tank
Engine bay with 3–4 methalox engines
Heat shield integrated around engine skirt
4. Mars EDL Sequence
1. Entry
Vehicle enters base‑first
Heat shield absorbs ~1.5–2.5MW/m²
Body flaps maintain attitude
2. Supersonic retropropulsion
Engines ignite at ~Mach 2–3
Vehicle slows to subsonic
3. Terminal landing burn
3‑engine burn → 1‑engine hover‑slam
Landing legs deploy
Touchdown at <1m/s
4. Bulldozer deployment
Vehicle tilts slightly using legs
Ramp deploys
Bulldozer drives out
Vehicle becomes a static power tower or communications mast
5. Payload Capacity Estimate
A Falcon‑9‑derived lander could deliver:
To Mars Surface
3–6t bulldozer
Plus ~1–2t of auxiliary equipment
Total landed mass: 5–8t
This is enough for:
A compact bulldozer
A regolith scraper
A blade‑equipped rover
Or a small autonomous grader
6. Why This Is Useful for Starship
Starship needs:
A flat pad
Compacted regolith
No large rocks
No slopes >5°
Your bulldozer lander becomes the first surface‑prep asset, arriving before the first crewed Starship.
This is exactly the kind of system that makes a Starship landing zone safe and repeatable.
7. If you want, I can produce next:
A blueprint‑style top‑down layout of the redesigned booster
A cutaway diagram showing tank and payload arrangement
A Mars bulldozer design sized to fit inside the 3.66m fairing
A landing sequence diagram
A mass budget for the entire lander
A site‑prep workflow for building a Starship landing pad
Just tell me which direction you want to push this design next.
Raptor engines for vacumn seems the right path for the engine replacement
See my thinking
You’re thinking in the right direction—Raptor‑class methalox is exactly the family you want. Using vacuum Raptors (or Raptor‑vac–derived engines) for a Falcon‑9‑derived Mars lander actually lines up with several of your needs:
Why Raptor‑vac (or vac‑derived) makes sense
Methalox commonality with Starship:
Fuel: CH₄/LOX matches Starship ISRU plans.
Your bulldozer, power systems, and later surface assets can all be designed around the same propellant ecosystem.
High Isp in thin atmosphere:
Mars’ atmosphere is thin enough that a vacuum‑optimized nozzle works well for most of descent.
You get higher Isp than a sea‑level engine, which directly improves landed mass for the same tank volume.
Deep throttling for terminal descent:
Raptor‑class engines are designed with significant throttle range.
For Mars, you want:
Multi‑engine ignition for redundancy and high‑g braking.
Ability to drop to single‑engine low‑thrust for the last ~100–200m.
Supersonic retropropulsion heritage:
Starship’s Mars EDL concept is built around supersonic retropropulsion with Raptors.
Reusing that logic on a smaller, F9‑sized lander keeps the architecture coherent.
Design tweaks for using Raptor‑vac on a 3.66m stage
Engine count and clustering:
Likely 3 Raptor‑vac–derived engines in a tight cluster.
Outer diameter of nozzles will dominate the base geometry; you may need:
Slightly truncated nozzles, or
1 full‑vac + 2 “mid‑expansion” engines for better gimbal and clearance.
Heat shield integration:
Base heat shield must be annular around the engine cluster.
Engines are protected behind a deployable or sacrificial skirt during peak heating, then exposed for retroprop.
Landing leg geometry:
Legs attach to the interstage/engine section ring outside the nozzle circle.
You want a 6–8m footprint, so legs must fold up along the tank and swing out wide.
Operational logic with Raptor‑vac
Entry:
Base‑first, shielded, no engines exposed.
Supersonic retropropulsion:
Skirt opens or ablates away.
3 Raptors ignite, high thrust, high Isp, rapid decel.
Subsonic/terminal:
Drop to 1 engine, deep throttle.
Use gimbal + body flaps for attitude.
Land at <1m/s.
If you like this direction, next we can:
Rough out a mass budget for a 3‑Raptor‑vac Mars lander based on F9 geometry, or
Lay out a plan view of the engine bay + leg attach points, or
Size the bulldozer mass and dimensions that still close the propellant budget.
Which of those do you want to lock in first?
show design for increasing diameter so that rocket gets shorter
See my thinking
You’re going after exactly the right instinct here—make it fatter and shorter so it’s more stable, easier to land, and can actually house a meaningful bulldozer. Let’s turn the Falcon‑9‑derived Mars lander into a “stubby” methalox lander and walk through a clean redesign.
1. New overall geometry
Let’s pick a concrete target so we can reason clearly:
Diameter: 6m (up from 3.66m)
Total height: ~24m (down from ~42m)
Aspect ratio: 4:1 instead of ~11:1 → much more stable on legs
Payload bay internal diameter: ~5.5m
Payload bay height: 6–8m
This keeps it big enough to carry a serious bulldozer, but compact enough to land without feeling like a pencil on stilts.
2. High‑level stack layout
From top to bottom:
Payload bay (bulldozer compartment)
LOX tank
CH₄ tank
Engine bay + base heat shield
Landing legs attached around lower tank section
A simple side view (not to scale, but to orient thinking):
┌───────────────────────┐
│ Payload bay │ ← Bulldozer + ramp
│ (5.5 m ID, 6–8 m) │
└─────────┬─────────────┘
│
┌─────────┴─────────────┐
│ LOX tank │
│ (~6–7 m) │
└─────────┬─────────────┘
│
┌─────────┴─────────────┐
│ CH₄ tank │
│ (~5–6 m) │
└─────────┬─────────────┘
│
┌─────────┴─────────────┐
│ Engine bay + heat │
│ shield (3 Raptors) │
└───────────────────────┘
/ / / / /
/ / / / / ← Wide landing legs (8–10 m footprint)
3. Engine and base redesign
With a 6m diameter, you can comfortably cluster 3 Raptor‑vac–derived engines:
Engine circle:
1 center engine
2 or 3 around it (you can choose 3 or 4 total depending on thrust needs)
Nozzle clearance:
6m base gives room for large expansion ratios without clipping the legs
Heat shield:
Circular base shield with cutouts or a central opening for the engine cluster
Engines recessed slightly into the shield cavity for better protection during entry
This geometry also makes it easier to:
Integrate thicker leg attach points into the lower skirt
Route methane and LOX feedlines with more gentle bends and better insulation
4. Landing leg geometry and stability
With a 6m body, you can push the leg footprint out to 9–10m:
Leg count: 4 or 6
Footprint radius: 4.5–5m
Tip‑over angle:
For a 24m tall vehicle and 10m footprint, the tip‑over angle is much improved vs a tall 3.66m stack.
You can also lower the center of mass by:
Keeping the bulldozer as low as possible in the bay
Using the LOX tank above CH₄ (denser fluid higher, but still below payload)
You can also integrate:
Crush‑core pads for rocks
Optional auger‑style feet to bite into regolith if you want semi‑permanent anchoring
5. Payload bay and bulldozer envelope
With a 6m outer diameter:
Internal diameter: ~5.5m (allowing for structure + insulation)
Usable height: 6–8m
That gives you a bulldozer envelope roughly:
Width: up to ~4.5–5m
Height: up to ~3m
Length: aligned with the axis, up to ~5–6m
Deployment options:
Side ramp:
A large side door in the payload bay wall
Ramp folds down to the surface
Vehicle can kneel slightly on one side using leg actuators to reduce ramp angle
End‑on deployment:
Bulldozer nose toward the side door
Drive straight out and down
6. Mass and performance intuition
By going wider and shorter:
Structural mass fraction improves
Shorter tanks → less bending moment → lighter structure for same loads
Landing stability improves
Lower center of mass, wider stance
Payload bay becomes actually useful
You can realistically land a 5–8t bulldozer plus support gear
At a high level, a 6m‑diameter, 24m‑tall methalox lander with 3 Raptor‑vac–class engines can plausibly:
Land ~10–15t total payload on Mars (depending on exact tankage and staging)
Dedicate 5–8t of that to the bulldozer and pad‑building equipment
7. Where we can go next
If you want to tighten this up, we can:
Lock in exact dimensions for a 6m or 7m version (height, tank lengths, bay height).
Do a first‑order mass budget: dry mass, prop mass, landed payload.
Sketch a plan view of the engine bay and leg attach points.
Or design the bulldozer itself to fit this 5.5m internal diameter.
Which one do you want to nail down first—the exact geometry of the lander, or the bulldozer envelope?
is there a way to lower the payload so that the out shell can be used as a drop ramp to get the bull dozer to the surface
See my thinking
Yes—there’s a very clean way to do this: treat the lower side of the payload shell as a hinged clamshell that becomes the ramp, and deliberately mount the bulldozer as low as possible in the stack so it’s almost at ground level when you land.
Here’s a concrete version that works with the stubby 6m‑class lander we just sketched.
1. Lowering the payload inside the stack
Goal: put the bulldozer’s wheels/tracks only a few meters above the surface at touchdown.
Payload bay position:
Instead of sitting entirely above the LOX tank, the bulldozer bay overlaps the upper tank section.
You create a “saddle” structure around the upper LOX tank dome so the bulldozer can sit lower in the vehicle.
Internal deck:
A structural payload deck is placed just above the methane tank dome.
Bulldozer is hard‑mounted to this deck during flight.
Resulting height:
Bulldozer floor might be only 4–5m above the ground when landed, instead of 8–10m.
Very rough side view:
┌───────────────────────┐
│ Upper payload shell │
│ (avionics, etc.) │
├────────────┬──────────┤
│ Bulldozer │ │ ← Bulldozer sits in a “saddle” around LOX dome
│ bay │ │
└───────┬────┴──────────┘
│ Payload deck ← as low as possible
┌───────┴───────────────┐
│ LOX dome │
│ CH₄ tank │
└────────┬──────────────┘
│ Engine bay

2. Using the outer shell as a drop ramp
Now we turn part of the cylindrical shell into the ramp itself.
Clamshell segment:
Take a ~90–120° arc of the lower payload shell on one side.
Hinge it along the bottom edge, just above the leg attach ring.
During entry:
This shell segment is fully closed, forming part of the aeroshell.
It carries TPS on the outside and structural stiffeners inside.
After landing:
Internal latches release.
Hydraulic actuators or screw jacks rotate the shell outward and downward until it rests on the surface as a ramp.
So the “wall” of the lander becomes the ramp.
3. Making the ramp actually usable
To make that ramp workable for a bulldozer:
Kneeling the lander:
Use landing leg actuators to lower the vehicle slightly on the ramp side, reducing ramp angle.
Ramp geometry:
Length of the shell segment: full height of the bulldozer bay (say 5–6m).
When rotated down, that gives you a long, shallow ramp.
Ramp surface:
Inside of the shell is pre‑equipped with:
Traction ribs or grating
Side curbs to prevent slipping off
Transition lip:
The payload deck has a small hinged lip that folds down to bridge any gap between deck and ramp.
Sequence:
Land.
Verify stability, kneel slightly toward ramp side.
Vent/depressurize bay if needed.
Release latches, swing shell down into ramp position.
Deploy deck lip.
Bulldozer drives straight out and down.
4. Structural and EDL considerations
Strength during entry:
The clamshell/ramp segment must be fully locked into a ring frame so it behaves like a normal fuselage panel under aero and thermal loads.
Hinge and latch design:
Hinges at the bottom are massive, simple, and shielded from direct heating.
Latches at the top and sides carry most of the hoop load during flight.
Dust and sealing:
Use labyrinth seals and TPS blankets along the seams.
You don’t need it airtight for crew—just structurally continuous and thermally protected.
5. Why this is a good fit for your bulldozer mission
You get a very low‑complexity deployment: no cranes, no elevators.
The outer shell does double duty: aeroshell in flight, ramp on the ground.
By lowering the bulldozer bay around the tank dome and kneeling the lander, you can get the effective ramp angle into a comfortable range for a heavy tracked vehicle.
If you want, next we can:
Fix exact dimensions for the ramp segment and deck height, or
Define a bulldozer size and mass that fits this bay and can handle Mars regolith pad‑building.

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#3 2026-02-14 19:02:30

SpaceNut: Administrator; From: New Hampshire; Registered: 2004-07-22; Posts: 30,494

Re: Wiki Landing Site preparation mission

ok so lets talk about how to get the ship to mars so that it can be used.

could this rocket be sent with a fully fueled starship from earth orbit

Short answer: yes, in principle—a Falcon‑9‑derived, 6m‑class Mars lander with a 5–8t bulldozer can be sent along with a fully fueled Starship from Earth orbit, as long as we keep the lander’s wet mass in the right ballpark.
1. What Starship can move from Earth orbit to Mars
Starship, when fully refueled in Earth orbit, is designed to send on the order of ~100t of payload to Mars in a fully reusable mode.
So your constraint is roughly:
Mars‑transfer payload budget: ~100t (order of magnitude)
That 100t must include:
The lander dry mass
The lander propellant for Mars EDL + landing
The bulldozer and support gear
2. Plausible mass budget for your lander
For a 6m‑diameter, ~24m‑tall methalox lander with 3 Raptor‑vac–class engines:
Dry structure + engines + legs + TPS: ~25–35t (reasonable estimate)
Mars EDL + landing propellant: ~20–30t
Bulldozer + tools: 5–8t
That puts the total injected mass in the range of 50–70t, comfortably under Starship’s ~100t Mars‑transfer capability.
So yes—one such lander plus bulldozer is well within what a fully fueled Starship can push from Earth orbit to Mars.
3. How it would actually fly with Starship
Conceptually:
Launch & refuel:
Starship reaches LEO, is refueled by tanker flights.
Lander integration:
Your bulldozer lander is either:
Launched separately and docked in orbit, or
Pre‑integrated in Starship’s payload bay from the start.
Trans‑Mars injection:
Fully fueled Starship performs the burn, carrying the lander as payload.
At Mars:
Starship either:
Stays in orbit and deploys the lander, or
Enters a high‑elliptic capture and releases the lander for independent EDL.
As long as we keep the lander+bulldozer stack under ~70t, Starship has margin for trajectory shaping, comms gear, and maybe a second smaller payload.
If you’d like, next we can tighten that mass budget (assign specific numbers to tanks, engines, legs, TPS, bulldozer) and see exactly how much margin you’d have inside Starship’s ~100t Mars payload window.
lets see where we are with the mass budget
See my thinking
Great, let’s put numbers on this thing instead of vibes.
High‑level target
We want a lander + bulldozer stack that:
Stays comfortably under ~100t Starship‑to‑Mars payload (order‑of‑magnitude for cargo Starship).
Still has enough propellant to do full Mars EDL + powered landing.
Delivers a useful 5–8t bulldozer.
Let’s build a first‑pass mass budget for the 6m‑diameter, ~24m‑tall methalox lander with 3 Raptor‑vac–class engines.
Draft mass budget
Subsystem    Mass estimate (t) Notes
Primary structure + tanks    15–20    6m dia, 24m tall, stainless or Al‑Li, domes, frames, decks
Engines (3× Raptor‑vac‑like) 6–9    2–3t per engine including gimbal, plumbing
Landing legs + mechanisms 4–6    4–6 legs, wide 9–10m footprint, actuators, crush cores
TPS + base heat shield    4–6    Tiles/ablator, base shield, ramp‑segment TPS
Avionics, power, GNC, comms 2–3    Computers, sensors, harness, antennas
Ramp/clamshell mechanisms 2–3    Hinges, actuators, latches, reinforcement
Margins & misc.    3–5    Piping, insulation, internal structure, contingency
Dry mass subtotal: ≈ 36 – 52 t
Let’s pick a working dry‑mass design point: 45t.
Propellant for Mars EDL + landing
We need enough methalox to:
Deorbit (if needed)
Perform supersonic retropropulsion
Do a terminal landing burn with margin
For a Raptor‑class lander, a reasonable first‑cut:
Propellant mass: 25–35t
Let’s pick 30t as a design point.
Now we’re at: ? lander, wet = 45 t (dry) + 30 t (prop) = 75 t
Bulldozer + tools
From the earlier envelope:
Tele‑operated electric dozer: 4–8t
Let’s pick 6t (D2/D3‑class electric, with batteries).
Tools, spares, support gear: 1–2t
Call it 8t total surface payload.
Now the full stack mass at Earth‑departure: ? total = 75 t (lander wet) + 8 t (payload) ≈ 83 t
Check against Starship’s Mars payload window
Cargo Starship is often framed around ~100t class payload to Mars when fully refueled in Earth orbit.
Our current design point:
Total to Mars: ~83t
Margin vs 100t: ~17t
That margin can cover:
Analysis/engineering reality creep (dry mass drifting up)
Extra propellant for more aggressive entry profiles
Additional surface equipment (solar, comms mast, small rover, etc.)
So at this level of fidelity, the answer is:
The 6m stubby lander + 6t bulldozer closes comfortably inside a Starship‑to‑Mars payload budget.
Where you might want to tighten next
We can now:
Push this into a more precise split (e.g., 6m vs 7m diameter, exact tank volumes, propellant mass from Δv).
Or lock the bulldozer: pick a 5–6t class machine and back‑solve the lander around it.
Or do a Δv‑based propellant sizing for a specific Mars entry profile and T/W.
Which knob do you want to turn first—lander geometry refinement, or a more exact Δv/propellant calculation?
Lets assume that the payload is refueled at the same time as the starship so that it can be launched from earth to orbit within a taller ship
See my thinking
Nice—this is a really powerful assumption, and it actually makes your architecture cleaner, not messier.
You’re basically saying:
Launch the lander inside a (slightly taller) cargo Starship, mostly dry, then refuel both Starship and the lander in Earth orbit before the Mars transfer burn.
Let’s walk through what that buys you and what it changes.
1. Launch configuration: lander inside a taller Starship
Geometry assumption:
Lander: ~24m tall, 6m diameter
Starship cargo bay (current): ~9m diameter, ~18m tall usable volume
So you’d need either:
A taller cargo Starship variant, or
A “double‑deck” internal arrangement where part of the lander extends into an upper volume.
Simplest mental model:
A “stretched cargo Starship” with ~25–30m of internal height.
Lander stands upright, hard‑mounted to a structural ring at the base.
Nosecone closes over it like a fairing.
On ascent:
Lander is mostly dry or partially fueled.
Starship carries it to LEO as pure payload.
2. Refueling both Starship and the lander in orbit
Once in LEO:
Tanker flights arrive and refuel Starship’s main tanks.
A portion of that transferred propellant is routed to the lander’s methalox tanks:
Via docking interface between Starship and the lander
Or via a propellant transfer umbilical inside the cargo bay
Key point:
You’re no longer constrained by launch mass from Earth for the lander’s propellant—only by on‑orbit refueling capacity.
So your earlier propellant budget (e.g., 30t) can be:
Kept as‑is for a pure descent lander, or
Increased (e.g., 40–50t) if you want:
More aggressive EDL profiles
Extra divert capability
Or even partial ascent capability for sample return or relocation
3. Impact on the mass budget
Previously we had a rough design point:
Dry lander: ~45t
Propellant: ~30t
Bulldozer + gear: ~8t
Total to Mars: ~83t
With orbital refueling of the lander, you can choose between:
Option A — Keep it conservative
Keep 30t propellant
You just gain margin on Earth launch (lander can go up nearly dry).
Starship still sends ~83t to Mars.
Option B — Increase lander propellant
Bump lander propellant to 40–50t without worrying about launch mass.
New stack (example with 45t dry, 45t prop, 8t payload): ? total ≈ 98 t
Still within a ~100t Starship‑to‑Mars window.
Now you have:
Very robust EDL
Big divert margins
Potential for limited ascent or hop capability on Mars.
4. Operational sequence with this architecture
Launch:
Stretched cargo Starship launches with lander inside, mostly dry.
Orbit & refuel:
Tanker Starships refuel the carrier Starship.
Lander is filled via internal plumbing/docking.
Trans‑Mars injection:
Fully fueled Starship + fully fueled lander depart LEO.
At Mars:
Starship performs capture or flyby.
Lander separates, performs its own EDL and landing.
Bulldozer deploys and starts pad prep.
Starship can then:
Stay in Mars orbit as a comms/relay node, or
Eventually attempt its own EDL (in later missions).
5. Why this is a strong architecture
Decouples Earth launch constraints from lander propellant needs.
Lets you oversize the lander’s propellant for safety and flexibility.
Keeps the bulldozer lander as a self‑contained, reusable asset that can be:
Delivered early
Potentially reused for multiple pads or sites

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#4 2026-02-14 19:09:22

SpaceNut: Administrator; From: New Hampshire; Registered: 2004-07-22; Posts: 30,494

Re: Wiki Landing Site preparation mission

Seems that we have plenty of mass even when bumping the starship payload mass such that we could make this a reality.

the lander is expendable and solar could be swapped with kilowatt reactor to charge the bull dozer as required.
See my thinking
Good—making the lander expendable and giving the dozer a kilowatt‑class reactor instead of solar actually simplifies the architecture and tightens the role of each element.
Here’s how that changes the picture.
1. Expendable lander: what we can strip out
If the lander never has to move again after touchdown:
No ascent/hop capability:
We only size propellant for EDL + landing, not for any Mars ascent.
No reuse margins:
Structural life can be single‑use with safety margin, not multi‑mission.
No need for precision refuel interfaces on Mars:
All refueling happens in Earth orbit; on Mars it’s a dead‑end asset.
That lets us:
Keep dry mass around 40–45t instead of creeping higher for reusability.
Keep propellant around 30–40t (robust EDL, no ascent).
Stay in the ~80–90t total band including the bulldozer and reactor.
2. Swapping solar for a kilowatt‑class reactor
Instead of a big solar farm:
Reactor power level:
Think 10–40kWe continuous, not megawatts.
Enough to slow‑charge the bulldozer between work shifts and run comms, heaters, and local systems.
Mass:
A compact fission system in that range is plausibly 2–5t including radiator, shielding, structure.
Location:
Either:
Mounted on the lander deck with a deployable mast to move it away from the hull, or
Delivered as a separate pallet that the bulldozer drags to a standoff distance.
You’ve effectively turned the lander into:
A one‑time delivery bus for:
Bulldozer
Reactor
Maybe a small comms mast and local infrastructure
Once empty, the lander is just a tower and structural anchor.
3. Bulldozer + reactor operational concept
Day 0–1:
Lander touches down.
Ramp drops, bulldozer drives out.
Reactor is deployed to a safe distance (towed or on its own mobility base).
Ongoing:
Bulldozer works in duty cycles:
Work for a few hours → return to charging point → repeat.
Reactor provides:
Charging power
Heat for local equipment
Stable power for comms and sensors
No dependence on dust‑sensitive solar, no need for huge arrays before Starship arrives.
4. Updated mass picture (first‑pass)
Rough design point with expendable lander + reactor:
Lander dry: ~40–45t
Propellant (EDL only): ~30–35t
Bulldozer: ~6t
Reactor system: ~3–4t
Misc. surface gear: ~2t
Total to Mars: ≈ 81 – 92 t
Still inside a ~100t Starship‑to‑Mars envelope, with some margin.

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#5 2026-02-14 19:15:07

SpaceNut: Administrator; From: New Hampshire; Registered: 2004-07-22; Posts: 30,494

Re: Wiki Landing Site preparation mission

modified staship is also is expendable
See my thinking
Got it—so now we’re in a fully expendable stack:
Expendable carrier Starship
Expendable 6m lander
Expendable lander‑delivered reactor + bulldozer
Let’s lock where the mass budget sits under that assumption.
1. Expendable Starship → what changes for us
If Starship is expendable on this mission:
It doesn’t need:
Earth‑return TPS margin
Earth‑landing propellant
Structural life for multiple flights
Practically, that means:
More of its on‑orbit propellant can be spent on TMI and Mars capture, or
It can carry more payload mass for the same refueling effort.
For our purposes, the key effect is:
Our ~80–90t lander+bulldozer+reactor stack is now even more comfortably inside what an expendable, fully refueled Starship can throw at Mars.
We don’t need to increase payload mass—we just gain margin.
2. Current best‑guess mass budget (expendable lander + reactor)
Let’s freeze a clean design point:
Lander dry (expendable): ~40–45t
Structure, tanks, 3 Raptor‑vac‑class engines, legs, TPS, ramp, avionics
Lander propellant (EDL only): ~30–35t
No ascent/hop capability, just robust EDL + landing margin
Bulldozer: ~6t
Tele‑operated, battery‑electric, D2/D3‑class
Reactor system: ~3–4t
10–40kWe class, including shielding, radiators, structure
Misc. surface gear: ~2t
Comms mast, tools, spares, small pallets
That gives: ? total ≈ 81 – 92 t
Call it ~90t to Mars as a round design number.
For an expendable, fully refueled Starship, that’s very plausible with margin.
3. Architecture summary in this expendable world
Launch:
Expendable cargo Starship (possibly stretched) launches with the 6m lander inside, mostly dry.
LEO refueling:
Tanker flights refuel Starship.
Lander is filled with ~30–35t methalox via internal plumbing.
TMI:
Expendable Starship spends whatever prop it needs to send ~90t to Mars.
At Mars:
Lander separates, performs EDL and landing.
Starship can:
Aerobrake and be abandoned in some orbit, or
Follow a disposal trajectory—either way, it’s not coming home.
Surface:
Lander is static infrastructure.
Ramp drops, bulldozer deploys.
Reactor is deployed/towed to a safe standoff distance and charges the dozer indefinitely.
Dozer builds and maintains Starship pads.

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#6 Yesterday 12:15:00

SpaceNut: Administrator; From: New Hampshire; Registered: 2004-07-22; Posts: 30,494

Re: Wiki Landing Site preparation mission

Describing something like this

file.php?id=237

here is the WIKI Constructing things on Mars equipment needs

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#7 Yesterday 19:32:24

SpaceNut: Administrator; From: New Hampshire; Registered: 2004-07-22; Posts: 30,494

Re: Wiki Landing Site preparation mission

asking for engine and propellant change

I would like to change engines to the super draco and hydrogel fuels
See my thinking
You’re making a pretty big architectural pivot here—doable, but it changes the whole “ecosystem logic” of the lander.

Let me split this into two parts: SuperDraco reality, and what “hydrogel fuels” could mean in a Mars context.

SuperDraco as main landing engines
What they are:

Type: Hypergolic, pressure‑fed engines

Propellants: NTO + MMH (or similar)

Thrust (per engine, vacuum): ~73 kN

Isp: ~235–250 s (much lower than Raptor‑class methalox)

To match your previous 600–800 kN thrust band, you’d need on the order of:

8–12 SuperDracos clustered around the base

Total thrust:

8
×
73
≈
580
kN
to
12
×
73
≈
876
kN
Implications:

Pros:

Very deep throttling.

Instant start/stop, multiple restarts.

Mature tech, simple pressure‑fed plumbing.

Great for terminal descent and hover‑slam control.

Cons:

Much lower Isp → more propellant mass for the same Δv.

Toxic, corrosive propellants → handling, contamination, and long‑term surface ops issues.

Breaks methalox commonality with Starship and ISRU.

For an EDL‑only expendable lander, SuperDracos can work, but your wet mass will go up for the same performance, or your payload will go down for the same mass.

“Hydrogel fuels” — what do you mean?
This phrase is ambiguous, and it matters a lot. It could mean:

Gelled hypergolic propellants (e.g., gelled MMH/NTO or green hypergols)

Gelled cryogenics (e.g., gelled LOX/CH₄ or LOX/H₂)

Green monoprop/bi‑prop gels (AF‑M315E‑like, but gelled)

Each of these has different:

Density (affects tank size and lander geometry)

Storability (important for months‑long cruise to Mars)

Isp (directly hits your landed mass or bulldozer size)

If you want a SuperDraco‑style, pressure‑fed, storable system, the most realistic interpretation is:

Gelled hypergolic bi‑prop (storable, higher density, slightly better safety/handling than classic NTO/MMH, but still not “nice”).

What changes in the lander if we go SuperDraco + storable gel?
Structurally and operationally, your landing system can stay almost the same:

Same 6 m diameter, ~24 m tall lander

Same clamshell ramp

Same wide landing legs

Same bulldozer + reactor payload

But under the skin:

Engine bay:

Ring of 8–12 SuperDraco‑class engines instead of 3 big Raptors.

Smaller nozzles → more clearance for legs and heat shield cutouts.

Tanks:

Two storable‑prop tanks (oxidizer + fuel gel) instead of LOX/CH₄.

Likely smaller volume (higher density) but higher mass fraction (heavier tanks, pressurization).

Mass budget:

More propellant mass for the same Δv because of lower Isp.

But simpler feed system (pressure‑fed, no turbopumps).

Net effect: the lander probably stays in the same 80–90 t to Mars band, but:

You trade methalox efficiency + ISRU compatibility
for

Storability + simplicity + SuperDraco heritage.

Where I’d suggest we go next
Before I lock in numbers, I need one thing from you:

When you say “hydrogel fuels,” do you mean:

Gelled hypergolic storable propellants (SuperDraco‑like, pressure‑fed, toxic but simple), or

Some kind of gelled methalox / cryogenic system (trying to keep CH₄/LOX in a gel form), or

Something else entirely that you have in mind?

Once you pick (1) or (2) (or clarify your own idea), I can:

Rebuild the mass budget for a SuperDraco/gel lander, and

Redraw the engine bay + leg layout around a ring of smaller engines instead of 3 big Raptors.

redraw
Great — since you said “redraw”, I’ll give you a clean, updated layout of the lander specifically redesigned around SuperDraco‑class engines and gelled hypergolic propellants, instead of methalox Raptors.

This is a full architectural redraw, not just a tweak.
Here’s the new configuration, optimized for:

8–12 SuperDraco engines

Storable gel hypergolic propellants

Expendable lander

Clamshell ramp deployment

6‑meter diameter, ~24‑meter height

? REDRAWN LANDER — SUPERDRACO + GEL PROPELLANT VERSION
Below is the updated geometry and subsystem layout.

1. Overall Shape (Side View)
Code
┌───────────────────────────┐
│ Payload Bay │
│ (Bulldozer + Reactor) │
│ 5.5 m ID × 6–8 m tall │
└───────────┬───────────────┘
│
┌───────────┴───────────────┐
│ Upper Gel Oxidizer Tank │
│ (Gelled NTO derivative) │
└───────────┬───────────────┘
│
┌───────────┴───────────────┐
│ Lower Gel Fuel Tank │
│ (Gelled MMH derivative) │
└───────────┬───────────────┘
│
┌───────────┴───────────────┐
│ Engine Bay (8–12 SDs) │
│ Ring‑mounted SuperDracos │
└────────────────────────────┘
\ \ \ \ \ \ \
\ \ \ \ \ \ \
Wide 9–10 m landing legs
2. Engine Bay (Top‑Down Redraw)
SuperDracos are small, so we use a ring layout instead of a central cluster.

Code
┌───────────────────────┐
│ 6 m dia │
│ │
│ ○ ○ ○ ○ ○ │
│ ○ ○ │
│ ○ ○ ○ ○ ○ │
└───────────────────────┘
Legend:

○ = SuperDraco engine

Engines evenly spaced around the perimeter

8, 10, or 12 engines depending on thrust requirement

Why this works
SuperDracos are pressure‑fed, so no turbopumps.

Ring layout gives:

Excellent gimbal authority

Redundancy (you can lose 1–2 engines)

Clear space in the center for:

Landing leg actuators

Ramp hinge structure

Propellant feed manifolds

3. Propellant Tanks (Gelled Hypergolic)
Upper Tank: Gelled Oxidizer (NTO‑derived)
High density → smaller tank volume

Storable for months → ideal for Mars cruise

Pressure‑fed → spherical or near‑spherical dome

Lower Tank: Gelled Fuel (MMH‑derived)
Also storable

Slightly lower density than oxidizer

Sits above engine bay for short feedlines

Tank Geometry
Because gels are denser than cryogenics:

Tanks are shorter

Lander can be shorter overall

Center of mass is lower, improving landing stability

4. Clamshell Ramp (Updated for Hypergolic Layout)
The ramp system stays almost identical to the methalox version, but the internal structure changes:

Ramp hinges attach to the lower tank ring, not the engine skirt.

Gel tanks allow more internal volume near the bottom → bulldozer can sit even lower.

Ramp length: 5–6 meters

Ramp angle after kneeling: 15–20°

Ramp Sequence
Lander kneels on ramp side

Clamshell unlatches

Ramp swings down

Deck lip deploys

Bulldozer drives out

5. Landing Legs (Unchanged Geometry)
Still using:

6 or 8 legs

9–10 meter footprint

Crush‑core pads

Optional auger‑tip anchors

SuperDraco ring engines give more clearance for leg mounts.

6. Mass Budget (Updated for Hypergolic System)
Hypergolic gels → lower Isp → more propellant needed.

New estimates:
Dry mass: 42–48 t

Propellant (gel): 35–45 t

Bulldozer: 6 t

Reactor: 3–4 t

Misc cargo: 2 t

Total to Mars: ~88–95 t
Still inside Starship’s expendable payload capability.

7. What This Redraw Achieves
✔ Fully storable propellants
No boiloff, no cryo insulation, no chilldown.

✔ Simpler plumbing
Pressure‑fed → no turbopumps → fewer failure modes.

✔ More engines = more redundancy
Lose one? Lose two? Still land.

✔ Lower center of mass
Gelled propellants are dense → tanks compact → bulldozer sits lower.

✔ Ramp deployment even easier
Shorter tanks = lower deck height = shallower ramp.

If you want, I can now produce:
A. A clean ASCII blueprint of the full lander
B. A top‑down structural diagram showing tank walls, ramp cutout, and engine ring
C. A mass‑optimized version (8 engines vs 12 engines)
D. A landing sequence diagram updated for SuperDracos
E. A bulldozer envelope drawing inside the new bay

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#8 Today 08:18:36

SpaceNut: Administrator; From: New Hampshire; Registered: 2004-07-22; Posts: 30,494

Re: Wiki Landing Site preparation mission

How to get large payloads to mars with smaller rockets require the EDL's to make it possible.

Here is one of the topics that contain the hyper cone
Ballistic Delivery of Supplies to Mars: Lithobraking post #9

Air bag drop

HIAD inflatable drag increasing

ADEPT umbrella heat shield

Here is what it looks like if things do not work

Heat Shield Design Manufacture Application Maintenance several posts contained all three types

Again multiple posts Heat on aerobreak

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#9 Today 09:04:35

SpaceNut: Administrator; From: New Hampshire; Registered: 2004-07-22; Posts: 30,494

Re: Wiki Landing Site preparation mission

Here is the topic Forty 40 Ton Mars Delivery Mechanism

Landing 40 metric tons or more at a time on the surface of Mars is a critical requirement for human missions, representing a massive technological leap from the ~1 metric ton currently landed by NASA's largest robotic missions.

Key Aspects of the "40 Tons to Mars" Challenge:
The Technical Challenge: Landing heavy, human-rated payloads (40–100+ tons) requires landing systems that can manage descent through the thin Martian atmosphere, a feat currently beyond proven operational capabilities.
Mission Requirements: NASA studies and industry experts suggest that approximately 40 to 80+ tons of useful, landed mass—including habitats, supplies, and return vehicles—are required per crewed mission.
SpaceX Starship Capability: SpaceX’s Starship is designed to carry over 100 tons of cargo to the surface of Mars, with plans to use the vehicle's large payload capacity to deliver infrastructure and enable propellant production (ISRU) on the surface.
Alternative Approaches: Some proposals suggest delivering 40 tons of return propellant directly, or alternatively, delivering 40 tons of water to be converted into propellant on the surface to simplify missions.

Challenges and Solutions:
Entry, Descent, and Landing (EDL): Because the Martian atmosphere is too thin to slow down heavy spacecraft with parachutes alone, new technologies like supersonic retro-propulsion are necessary.
Power and Infrastructure: Landing 40+ tons allows for the deployment of heavy, efficient power sources (such as nuclear reactors) rather than relying on massive solar arrays.
Return Trip: The 40-ton target is often tied to delivering the necessary equipment to produce return propellant on-site (In-Situ Resource Utilization - ISRU).

The goal of landing 40+ tons is considered crucial for making human exploration, and potential settlement, of Mars viable by the 2030s-2040s

How to make a hard surface might be the issue to solve once we are there

Starship concrete Mars landing pad

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