[valuearb]

The Space Shuttle payloads to LEO cost $40,000 per pound.

Before SpaceX commercial launch payloads cost $5,000 to $10,000 per pound.

Falcon 9 payloads cost around $1,500 per pound.

Falcon Heavy payloads cost around $1,100 per pound.

Starship payloads will cost between $100 and $500 per pound. It will be able to lift at least 100 tons to orbit. And using in orbit refueling, it will be able to accelerate that 100 ton payload 6.9 km/sec, making landing it on Ceres trivial.

[walrus01]

I am hopeful that Starship will really achieve those figures, but I am also skeptical... I'll believe it when I see it being done.

That's still not cheap enough to do lander/surface manipulation science in the asteroid belt without significant philanthropic or government funding.

At $500/pound, if a Ceres unmanned probe lander with drill/melting apparatus weighs 15000 kg when placed in low earth orbit (before whatever staging/fuel it expends to get to ceres and land), that's still a $16.5 million launch cost before you add the cost of the R&D to build the spacecraft, operate its command and control network, etc.

I will be very pleased and enthusiastic but also shocked if something like that is accomplished for a project budget under $30-40m in the next 20 years.

Not saying it's impossible but we're well within the realm of "big budget" science. Like the operating budgets of one of the smaller (not McMurdo or Amundsen-Scott) permanent research bases in Antarctica, or something like the this:

https://en.wikipedia.org/wiki/Chiky%C5%AB

Big enough that even top tier universities form consortia to collaborate in science projects such as the ALMA array.

[valuearb]

Starship will launch larger probes to Ceres than we’ve sent to Mars, for a lower launch cost. We will do what we’ve done on Mars.

[simonh]

True, but in orbit refuelling means 3 or 4 additional refuelling launches, so now your cost per kg is back up to a few thousand $ per kg again. Still cheap for Ceres though.

[imtringued]

Yeah, orbital refueling doesn't change the rocket equation unless you can manufacture fuel in space. The only benefit is that you don't need a bigger rocket.

[valuearb]

Orbital refueling absolutely changes the rocket equation in a huge way. The standard NASA human Mars plan involves a mega rocket large enough to lift the humans and their supplies in one shot from earth, along with the fuel to get to Mars and the fuel to get back.

Starship enters LEO with empty fuel tanks, meaning it can lift much more payload per pound of fuel. Being refueled in orbit is cheap, because fully reusable flights are cheap. And for Mars, Starship only needs enough fuel to get there, it can make fuel on Mars. That means it doesn’t have to carry even more fuel to fly the return fuel to Mars.

[rbanffy]

We'll eventually get to the point where Starship-like rockets only ferry people, cargo, and, maybe, propellant to LEO for transfer to spaceships that don't need to go deep into any gravity well. These ships will then take you to orbit around your destination so you can board another shuttle to the surface.

[valuearb]

That would be massively inefficient for travel to Mars, because you can Aerobrake to land and make fuel on Mars for your return.

[UnFleshedOne]

You could probably aerobrake to get into orbit instead. But eventually it might make sense to build ships that are never supposed to touch atmospheres, or only upper layers. Some design constraints can be relaxed then.

[valuearb]

There definitely is a place for Aldrin Cyclers, not soon, but eventually. It’s not to save on fuel, but to provide safer and healthier accommodations for the trip.

How it will likely work is passengers will take a Starship to orbit. It will be refueled in LEO, then accelerate to Mars injection velocity to match orbit with a passing Cycler. It will dock with the Cycler, passengers will switch to the Cycler for the duration of the journey. The Cycler will be much roomier, have better shielding, and likely rotate to provide Mars level artificial gravity. Passengers will have far better work, entertainment and workout options.

Once the Cycler approaches Mars, passengers will reboard their Starship, and it will Aerobrake to land, while the Cycler continues on in its orbit, which returns to Earth. The Cycler never slows to orbit either Earth or Mars, it just coasts between them but occasionally will need fuel for course optimizations.

The only problem is that Cyclers will take 9 months to go to or return from Mars. They will be like large cruise ships. Starship can make the trip to Mars in as little as 3 months, and some will still do that. They will be the equivalent of the long distance direct flight, trading a less comfortable and less healthy trip for a big time savings.

[rbanffy]

The most efficient propulsion methods are not suitable for atmospheric flight or landing because of their low thrust, but are excellent for long-duration interplanetary flight where you can "burn" for hours, or days, to change between parking and transfer orbits.

[SAI_Peregrinus]

Sort of true. The rocket equation doesn't account for the added weight of lifting the rocket itself, just the added fuel. Multiple launches can reduce the practical overhead, even if not changing the overhead in the limit of 0% rocket mass 100% fuel mass.

[eru]

You are right.

Manufacturing fuel in space would be the way to go.

Or eg have giant solar panels in orbit that power a laser to shine at your spaceships. Either to propel them directly, or to transmit power for their ion thrusters etc.

[valuearb]

A fully expended Falcon 9 launch costs around $50M. A partially reusable Falcon 9 launch costs around $25M.

Starship will be fully reused. It will launch a 5x larger payload than the partially reusable Falcon 9 at a lower launch cost. So somewhere in the $5M to $20M range.

Starship can be fully refueled in LEO with eight tanker flights, Even at $20m per flight, that costs no more than the Atlas V that just launched perseverance to Mars, only with 40 times more mass.