sevenperforce

According to Musk, recovering the side boosters on droneships is only a 10% payload penalty from full-expendable. Even if he is exaggerating and the penalty is more like 15%, that suggests more than 54 tonnes to LEO with side-core reuse. So the Dynetics lander is easy AF if you expend the center core. With triple-core recovery FH can send 8 tonnes to GTO, which is 2.27 km/s. With a 4.1-tonne FHUS, that means it reaches LEO with prop residuals of at least 11.4 tonnes and a total mass of 23.5 tonnes. So it can probably send at least 19.4 tonnes to LEO with a burn to MRS. That checks out generally because an expendable F9 sends just slightly more to orbit than a triple-core-reuse FH, and F9's expendable LEO payload is 22.8 tonnes. NOt quite enough for the Dynetics lander. What about the TLI burn, if FH launches naked with triple-core reuse? We know that it reaches LEO with at least 11.4 tonnes of propellant carrying an 8-tonne payload, so it will have around 20 tonnes of propellant (probably a little more) if it launches naked. If you mate a 27-tonne payload to it, that's just shy of 1.7 km/s, which is not enough for GTO, let alone TLI. But there's another solution. Use FH with triple-core-recovery to send only the lander and inboard tanks to LEO, then use FH with an expended center core to send the drop tanks to LEO. The lander can do transposition, docking & extraction with the first drop tank, then rotate and dock with the second drop tank, which can remain fixed to the FHUS for TLI, which it can do easily.

FH with side-core reuse can deliver 15 tonnes direct to NRHO in a week. Fully reusable FH can't even send 8 tonnes to TLI. But he is correct that there are very low-dV trajectories to get to NRHO if you have plenty of time.

I think it depends in part on whether SpaceX is able to pull off its plan for higher-powered unthrottleable fixed-gimbal SL Raptors. If they can manage those, then that will really give Superheavy a ridiculous amount of thrust off the pad and a lower dry mass. Better TWR means cheaper RTLS.

Why not just build a second landing pad a safe distance away and use that one (with a crawler or crane to move it over) until they get it reliable?

Always SpaceX. According to Bruno at the original Vulcan announcement, baseline Vulcan is half the $164 tag of the baseline Atlas V. So if you are going to be using two of them, the price will vastly exceed one FHe. FH expendable can send 16.8 tonnes to Mars, which is at least 3.93 km/s beyond LEO. TLI is 3.2 km/s and NRHO injection is 430 m/s, so a total of 3.63 km/s. Assuming a dry FHUS mass of 4.1 tonnes and backing out the 3.93 km/s gives 45.26 tonnes of props in LEO. Getting 3.63 km/s at 348 s isp requires 65.5% of your m0 to be propellant, so a little math gives an estimated payload to NRHO of 19.74 tonnes. Probably a little lower given a heavier FHUS, boiloff, and more expensive LEO insertion. If it flies with only an expended core then probably closer to 17 tonnes.

Can you add a "Plutonium" category for submissions which utterly and completely blow away all of your expectations?

Adding a pusher plate does nothing. Materials on that scale wouldn't even work. It's precisely because the planet is a liquid droplet that you can use an entire continent as your pusher plate and the mantle as your shock absorber, if that's your aim. That's why you use the ablative properties of your pusher plate: https://what-if.xkcd.com/13/ Seriously, the only way to actuall do anything like this is to use successive gravitational flybys. Gravity works well for that.

The lunar ascent module, less engine, had a dry mass of 2.1 tonnes and a wet mass of 4.6 tonnes. The descent module's dry mass, less engine, was 1.9 tonnes and its wet mass was 10.2 tonnes. If you assume conservatively that tank and structure mass ratio on the descent and ascent stages was similar (4.37:1), then that says the lunar ascent module's tanks were 572 kg. So the actual core of the ascent module was just 1.5 tonnes. Even with mass growth, 15 tonnes for the descent/ascent stage seems high. How much descent dV is your module producing and what's the dry mass? Option 1, but it's really not that bad. Using your numbers, send the 15-tonne core to LEO on pretty much anything. Send one of your 8.5-tonne drop tanks to LEO on pretty much anything, and do a docking to extract. Then, send Vulcan Centaur Heavy up with the second drop tank, dock, and perform TLI. Looks very good!!

Genetically engineer a photosynthetic, acid-resistant bacteria that can reproduce in aerosol form and loves to split CO2 into diatomic oxygen and carbon-carbon chains it uses to make its own encapsulation (which allows it to float). Accidentally release it on Earth and wipe out all life.

There are two ways to go about it, I suppose. Are the inboard tanks also droppable? If so, it's very straightforward. A new outboard tank is mounted to a new inboard tank on Earth (with sacrificial/expendable decouplers) and both are stacked on a Vulcan Centaur Heavy, which can send 7-8 tonnes direct to NRHO. The inboard tank interfaces with the lander via a docking port connection, so the lander (which has been loitering in NRHO since dropping astronauts off at Orion) uses whatever residuals it has to rendezvous with Centaur. It drops the tank on one side and then uses residuals from the tank on the other side to dock. Repeat with another Vulcan Centaur Heavy, and you're good to go. If the inboard tanks are permanent, then the docking connection is between the inboard and outboard tanks, and you need prop transfer from a dedicated refill launch. Challenging because you need to transfer fuel, oxidizer, and pressurant. Of course we don't know the engine cycle of the Dynetics lander yet. With those giant solar panels, an electrically-turbopumped methalox lander would be a good choice. Also simplifies prop transfer because you don't need pressurant or high-pressure fluid transfer. The whole thing really is an extraordinarily Kerballed solution. I'm assuming that the lander uses more than 7-8 tonnes of propellant per sortie, but if not then the whole refill operation could be done from a single Vulcan launch.

Agreed. 'Twas my proposal a few months ago. Use the same architecture to support cargo drops as you use for your human ascent element; common architecture helps demonstrate function and work out kinks. Drop-tank-based architecture beats propellant transfer unless you are literally Starship.

Looks like it to me. They don't appear to gimbal. Though at this point they don't really have the engines themselves so all that is spec.

You are correct -- very astute.

If you are pushing the whole planet you don't need a pusher plate.

I think momentum transfer is much faster.

We already have a giant chunk of reaction mass orbiting once every month if we need to move the earth. We could use hundreds of mass drivers on small asteroids to gravitationally nudge a large asteroid into an earth-crossing orbit, timing it such that it would slowly nudge the moon into a higher orbit over time. Repeating the process with additional larger asteroids would accelerate the process. Once the moon escaped, the network of Earth-crossing asteroids could be used to nudge it into a Venus-crossing orbit that would suck orbital velocity away from Venus on one pass and add it to Earth on the next. The moon would slowly transfer energy away from Venus and to the Earth, raising Earth's orbit. Of course you lose tides that way, but if the situation is so dire that you need to fly the Earth out to Jupiter then tides are probably a minor problem.

On the other hand... How is it Cynus-derived if it uses a completely different propulsion system?

Very.

What exactly can Vulcan Heavy Centaur V send to NRHO? Vulcan Centaur Heavy can put 7.2 tonnes direct in GEO, which costs 3.8 km/s past LEO assuming no inclination correction. TLI costs 3.2 km/s and NRHO off a powered lunar flyby is another 500 m/s. So 7-8 tonnes to NRHO seems like a fair estimate.

So hypergols on the transfer stage, possibly an IHI BT-4 (although with only 500 N of thrust that would make for some long burns), hydrazine monoprop RCS. Probably a bigger engine. Dual BE-7-based hydolox descent module with probable boiloff gas-gas RCS. Each BE-7 can lift 23 tonnes in lunar gravity so I expect that it has engine-out capability by gimbaling through the COM (which is nice and high). The lower thrust of an engine-out descent probably means briefer powered surface loiter (the fuel cells run on boiloff from residuals). Still nothing known about the LockMart ascent module other than a single engine. We also don't know whether the transfer stage will loiter in LLO to help transfer the ascent module back to Orion. That's technically more mass-efficient, but introduces some orbit-phasing challenges.

You'd need a heck of a lot of gimball - 35° off-axis just to get to 80% thrust. But you need this only on landing, Oh, so not like the new Poodle at all.

Plausible enough.

You would need a lot of antimatter. If you want to move a rocky planet, your best bet is to build a fusion-based rocket candle on a lightweight gas giant and use its gravity to grab the rocky planet and shuttle it to where you want to go.

As long as the props don't mix before something goes wrong it will only be a deflagration. It would actually be less damaging to have fully-fueled tanks go up in flames than to have even the the autogenous pressurant gas in both tanks mix and then ignite. For the test hop they will need to fly only partly full, but I wager that for the static fire they fill-er-up, if for no other reason than to reduce stresses on whatever hold-downs they may have.

Great job @jinnantonix! Can I ask how much dV you ended up using to get from TLI to Orion and then down to LLO?