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Comment by credit_guy | Hacker News Reader

Can I play devil's advocate here?

The Startship's booster has a propellant mix of 2800 tons of oxygen and 800 tons of methane [1]. Since in the reaction CH4 + 2 O2 = CO2 + 2 H2O there's 4 times as much oxygen by mass (2x32 = 64) than methane (12+4=16), it follows that only 700 tons of methane burn, and 100 are vented in the atmosphere.

This might not seem like much, but Musk has a goal of 1 million launches per year [2]. The EPA considers that one ton of methane is equivalent to 25 tons of CO2, so that brings us to 2.5 Gigatons of equivalent CO2 emissions.

Currently the whole of the US emits 6.0 Gigatons equivalent CO2.

Take a moment to ponder this.

[1] https://en.wikipedia.org/wiki/SpaceX_Starship#Super_Heavy_bo...

[2] https://techcrunch.com/2020/01/17/elon-musk-shares-details-a...

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Well, sure but that has nothing to do with approving a launch site.

If Starship was used to maximum extend it would basically replace the airline industry and it would have about the same amount of impact.

If that is acceptable to society depends. Potentially this can be made reusabilty in the future as well. At least its easier to make methane then to make jet fuel.

Starship could not replace the airplane industry and would get far worse gas mileage.

> The Startship's booster has a propellant mix of 2800 tons of oxygen and 800 tons of methane

How much of that is burnt in the lower atmosphere? Most orbital flight profiles involve quickly getting out of the atmosphere before adding horizontal velocity.

> Musk has a goal of 1 million launches per year [2]

Is this a mistake?

FTA: "SpaceX’s goal, according to Musk, is to ultimately send one million people to Mars by 2050"

Not all the launches will aim to sent people to Mars. Some will just send cargo, and some will send stuff to LEO.

FTA:

  Musk said that the spacecraft is being designed with the plan of flying [..] a total of more than 1,000 flights per year, per vehicle.
  Ultimately, Musk says that he hopes to achieve [...] a goal of hitting 1,000 in total in service over the course of the next decade.

So that's one million launches. That's corroborated by the goal of 100 megatons of cargo per year (given that each Starship can carry 100 tons to space).

> So that's one million launches.

In a decade. Not a year.

No. It will take a decade to build enough Starship to have 1000 in operation. At that point, each will launch 3 times a day, for a total of about 1000 a year. One million per year in total. Not tomorrow, but starting about a decade from now.

Getting a little pedantic, but presumably some of those will be heading to or from Mars at any given time.

Anyway, it’s a long ways out and has nothing to do with the immediate Starship launch plans.

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