[hutrdvnj]

And we need a transportation that is much more economical than rockets, otherwise it will always be very costly to lift a kilogram into space.

[helsinkiandrew]

Actually rocket fuel although very old fashioned doesn't seem that costly.

Falcon 9 flight to LEO costs $200K in fuel but can lift 22,800Kg. If a person and their seat could be squeezed into 200Kg that's only $2K per person. I think the biggest cost is that the forces and extremes of temperature mean the 'rocket' needs to be engineered and maintained very well as any small failure is likely to be catastrophic - its very hard to abandon ship or divert to the the nearest airport.

[zizee]

Rockets aren't inherently expensive. Air travel would also be prohibitively expensive if the aircraft was disposed of at the end of each flight.

If SpaceX's Starship plans come to fruition, the $/kg to orbit cost will fall dramatically.

[cm2187]

Not to talk about the environmental impact!

[DennisP]

Not necessarily that high with methane fuel. The exhaust is CO2 and water, and you can make it from water, CO2 in the air, and clean energy.

[dangerbird2]

And potentially near-zero emissions with hydrogen/liquid oxygen rockets. Of course, methane rockets probably ends up having lower emissions in practice due to hydrogen typically being produced in methods that emit CO2.

Ultimately, even if we massively increased the rate of rockets being launched, the greenhouse gas impact would be pretty minimal compared to cars, electricity, and cement production.