[goda90]

It's due to a lack of cheap, readily available energy. We have to constantly worry about fuel and debris because maneuvering isn't cheap, and any form of electromagnetic shielding that's could even theoretically be useful would have incredible energy usage.

[dredmorbius]

This from the race of clever monkeys extracting liquid sunshine at 5 million times the rate of formation.

The Saturn V stage 1 engine produced 166 GW of power, roughly the electrical generating capacity of France at the time.

https://en.m.wikipedia.org/wiki/Orders_of_magnitude_(power)

The total net metabolic rate of 7 billion humans is about 700 GW. 18.1 TW -- only 100x the first stage power, is the total average human power consumption as of 2013.

The 770,000 litres of RP-1 (kerosene) represent some 18.3 million tonnes of primaeval plant matter converted over tens to hundreds of millions of years into petroleum. Per unit volume, it's very nearly the highest energy-density fuel available from chemical reactions (hydrogen does better on a unit-weight basis, but even that buys you only a factor of three. Oh, and that's what the Saturn V used in its upper stages (where the volume requirements for LH2 were viable).

What you're wishing for is what you've already got.

https://en.m.wikipedia.org/wiki/S-IC

https://en.m.wikipedia.org/wiki/Energy_density

https://link.springer.com/article/10.1023/A:1026391317686

[Robotbeat]

?? No. It's due to lack of mass (for shielding and fuel). We produce lots of energy in orbit.

[goda90]

Getting mass into orbit is also difficult due to a lack of cheap, readily available energy.

[mikeash]

Energy costs are a tiny fraction of launch costs. If rocket fuel could be had for free, it wouldn't noticeably change overall costs.