Yeah - that's the point I think. Maybe OP thinks an ecothetmuc reaction is creating free energy!!

I think OP is imagining a perpetual energy generating reaction with no downside (such as reactants getting consumed). As /u/chemchris says, and I extend a bit... mass-energy does not get created or destroyed (noting Einstein's E=mc^2 converts mass to energy, as we see in nuclear fission).

My congratulations to you and your daughter for thinking big thoughts. I hope it inspires her to take up a career in aerospace or space sciences. If you want to see some eye-opening videos, go to YouTube and search for Gateway Spaceport LLC to watch together. I would dearly love to see this firm build a working prototype of this technology up on orbit. As to "why bother when we can launch from Earth", well just look at the scale that this firm is working at, and you figure out immediately that they are designing structures at orders of magnitude bigger than can be directly launched.

I guess (seeing your Ukraine flag!) you can blame the Russians for that 1960's Space Race. Couching that goal to get to the Moon (and safely back again) made space a national priority the likes of which it would not have seen on a pure-science budget. Arguably the Apollo-Soyuz era, leading to the ISS era was critical in the detante between the US and the USSR back then.

Actually, I think it's better to have a fleet of say 20, 50, or even 100 starship to launch at the same time as a fleet. In this way, even losing 1 or 2 would still allow you to complete the mission. This is the same idea as the rocket array on the Falcon 9, where the rocket can lose an en engine and still have redundancy to complete the mission.

This is where Musk and SpaceX have been planning for years. Where other rockets have used space grade kerosene (RP1) and liquid oxygen, or liquid hydrogen + oxygen, Musk knew he wanted to refuel natively from the Martian atmosphere, which is CO2 rich, then the best fuel would be methane and oxygen. Hence the new raptor engine burns methane amd oxygen. Plus the Starships can be configured as fuel browsers, freighters, human-rated travel or as "Pez" dispensers fir hundreds of Starlink satellites per launch. The goal is to fund interplanetary missions from massive commercial benefits of launching satellites around Earth, then to build a fleet of vehicles capable of hundreds of trips each ship, then refuel in Earth orbit to allow much bigger missions to Mars than could launch direct from Earth. And so on... its incredible really.

There's a couple of different issues with the ISS. one - it's at an altitude that needs regular boosting or else it would reenter. Not a big deal, but annoying that you need to add thrust to keep it at a low orbit, versus putting it out to say 1500km or 2000km alt and it could stay for centuries with no boosting. Second... the inclination of the ISS is not ideal to launch to the moon or the planets due to the plane change needed. It would be much better if the orbital apogee (highest point) were on a nodal point with the planets, and as high as possible, to minimize the Delta-V to exit the base on the right plane and trajectory.