Mars transit game changer

I've been using 5.7 km/s as the delta V for going to mars. Now mmeijeri points out this chart which allows a 1.1 km/s cost to mars. So how does that impact per passenger costs?

I have proposed the first mars mission send a dozen colonists on two BA330 class ships to prepare for those that follow because fewer means we really aren't serious about settling mars. Survival requires more than a few hands. The second mission sends 42 at a much lower cost per settler. With 54 colonists on mars you have more than enough to support a full industrial ecology (capable of full self sufficiency.) This means $75m per year is all the support they would require from earth (one Red Dragon lander every 2 yrs) and even that is not absolutely essential.

I'm going to assume a Falcon Heavy (FH) capable of launching 50mt for $100m. I'm also going to assume an upgraded BA330 to a 40mt BA700 with life support for 21. Musk has put the per passenger cost to orbit at $20m, but the FH would be able to launch a stretch Dragon with 42 passengers to orbit for about $2m to $4m each.

So we send 42 settlers to mars on two BA700 which includes the vacuum Merlin upper stage that put it in orbit at no extra cost. Assume 1mt for each passenger we have a dry weight per ship of about 70mt. Two ships tethered together provide gravity and redundancy. Update: See Mars ref. mission.

To get to the surface from mars orbit we need six Red Dragon landers which cost about $900m total to put in mars orbit which would be $22m per settler. This is the highest per colonist cost item so if there is a way to reduce this it could be another major game changer.

Putting a BA330 in orbit cost $100m for the BA330 and another $100m for the launch. Let's say a BA700 would have a total cost to LEO of $300m (or $600m for two.)

The final cost to consider is how much fuel to send 140mt on a delta V of 1.1 km/s using 340s engines at $2m per metric ton. Using Trent's calculator I get 194mt for fuel or 4 FH launches. So the fuel cost is about $1m per settler and the ship cost to orbit is $14m per each colonist (ship cost may be amortized over multiple flights.)

So that gives you a total cost of $41m per colonists vs. $81m I previously calculated. That's huge, our mission cost has been cut in half from $6b to $3b (and lower if we consider reusability.)

Compare that to Mars One $6b for 4 colonists vs. $3b for 42 colonists. The Mars One plan does include other costs beyond just transportation.

I still see no way to get to Musk's $500k per settler, but there is no real need.

Update: Martijn points out this low delta V is from very high Earth orbit to very high Mars orbit. This is true, so there are some costs not included in the above. Specifically, you have to move everything from LEO to EML1, but the most expensive item, fuel can go by the least expensive means (which is to say over time in perhaps small amounts.) The link above doesn't include mercury for a specific reason. All the planets on the chart have atmospheres to circularize orbits at almost no cost. Once the general purpose passenger ship arrives in high orbit around mars, Red Dragon landers will be both on the surface with supplies ready to prepare the site and landers in orbit to take them there. So the first order of business would be to circularize the passenger ships orbit so the landers could reach it. The ship will also probably need to carry fuel to top off the landers. More fuel gives them safer margins.

Update 2: The ships taking passengers to mars orbit would return empty to earth orbit for reuse. This could probably be accomplished with ion thrusters at very low cost relatively. Unused fuel could provide the initial push.