[cma]

>We are some decades behind this time.

Well, launching these 4 people does take over a ~~million gallons of kerosene~~ (edit: million lbs of CO2 emissions), so for the environment it is probably good that it isn't as common as jet travel yet. It will probably take fusion energy or mass solar, plus hydrogen rockets (emit only water).

[avhon1]

Where did you get the "over a million gallons of kerosene" figure? The figure I found [1] is 260,760 lbs in the first stage, which works out to almost exactly 25,000 US gallons in the first stage, which uses the large majority of the propellant.

The Wikipedia article [2] says 38,570 US gallons of RP-1 in the first stage and 4,500 US gallons in the second.

[1] https://web.archive.org/web/20170201135344/http://www.nmfs.n...

[2] https://en.m.wikipedia.org/wiki/Falcon_9

[cma]

I thought I heard that in their stream. Must have been a million lbs of fuel+oxygen and not a million gallons of fuel. Sounds like close to ~125,000lbs of CO2 emissions per passenger then.

With Starship being methane based (higher H to C ratio) and at bigger scale hopefully it gets that number down a lot.

This lists it at 1.1 million lbs fuel+oxygen and shows it being used with Dragon (did they use this or similar?): https://en.wikipedia.org/wiki/Falcon_9_Full_Thrust#Block_3

[mkl]

From the stream: "Prior to liftoff, the Falcon 9 first stage is loaded up with nearly one million pounds of fuel and liquid oxygen." - https://youtu.be/3pv01sSq44w?t=1920

[randallsquared]

There probably aren't going to be even 300 kerosene-burning Falcon 9 flights ever (this was number 127 or 128), because Starship is likely to start lifting commercial payloads by 2023 or 2024, and it burns methane, which could more easily than kerosene be part of a solar-power-to-rocket-fuel pipeline, recycling environmental CO2.

[elil17]

>could

Yeah but will it be? As it stands no rocket fuel is made in a clean way. As someone who very much intends to stay on Earth for the rest of my life, I feel well within my rights to be concerned that unneeded space travel is making stuff worse for us down here. Going into orbit is environmentally expensive, and society should use this technology judiciously.

[gravypod]

This is a fairly short sighted take. If SpaceX is able to commercialize space we could shift a lot of things that are traditionally difficult to off Earth even if you intend to remain here. For example, space provides a good method to pull a vacuum, run higher efficiency energy collection (solar/photo synthesis), or release byproducts of toxic manufacturing. Possibilities are very expansive. If we think of it this way: We will release X amount of CO2 to get a permanent space base which will save us an ongoing Y amount of CO2 forever in the production of some goods.

This is also assuming that there's no value in small, safe, steps on a path to socially acceptable space travel. Right now there's a perception of a lot of risk in going to space which is valid. If technology becomes safer over night no one will know it is safer. These incremental "we can launch", "we can reuse", "we can send a person", "we can send 4 people", etc messages are broadcasting to people that we can do this and that we are doing it. It's no longer science fiction.

[gpm]

> Yeah but will it be

Per Elon, yes, eventually [1].

It makes sense for them to do this too. They need the technology to be ready for mars. Positive PR is worth a lot in an industry heavily constrained by government regulations. The cost isn't likely to be that high compared to the rest of the costs involved in launching a rocket. If they're really lucky it will even help with the environmental regulators.

[1] https://twitter.com/elonmusk/status/1223018233638207488

[betwixthewires]

Spacex has the creation of CH4 as a priority, partly due to climate change and also as a development path for the tech needed to create fuel on the surface of Mars. Two (or more) birds with one stone is part of Elon Musk's very successful approach to getting things done, normally I'd agree with you but I think they will get it done before a Mars mission.

[lokimedes]

Water is a very potent greenhouse gas in the upper atmosphere.

[cma]

It doesn't accumulate long term in the same way as CO2 though, and kerosene burning makes water too.