[kant_adorn_arts]

Is the manufacture of biofuels actually carbon neutral? What about the massive deforestation of Indonesia - caused by Germany's biofuel mandate?

[kant_adorn_arts]

or is it not a biofuel? are they using the Sabatier reaction so they just need energy input (could be solar)?

[gpm]

Yes, the stated goal is the sabatier reaction from solar energy.

The apparent purpose of this is pretty much a tech-demo for mars. In terms of minimizing environmental impact on earth it would pretty clearly be better just to send the solar energy to the grid and divert natural gas that would have gone to generating electricity to launching rockets.

[ctdonath]

In context - using solar energy to extract atmospheric CO2 and manufacture methane - yes.

We're not discussing "massive deforestation" here. Germany's biofuel mandate does not affect rockets in Texas.

[MPSimmons]

Does shipping a rocket to Mars with enough propellant to make the trip and land when it gets there affect the balance?

Every rocket to Mars carries hydrocarbon that will never come back.