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Comment by JumpCrisscross | Hacker News Reader

> landing strip

Why are landing strips the big unlock? Blast effects? Tiny landing legs?

You could land at 500 km/h on wheels and use breaks to stop. This makes it much safer and lowers how much propellant you need to bring to the moon by a lot. Similarly it makes getting back into lunar orbit much safer and easier because you can use electric motors to propel a craft to around 500 km/h before ditching the wheels and starting your chemical rockets. This lowers your propellant mass by 30%.

Also the landing strip can be designed to slowly go up hill which could help with the breaking phase as well.

> you can use electric motors to propel a craft to around 500 km/h before ditching the wheels and starting your chemical rockets.

Makes me wonder if you could accelerate to orbital velocity using something like a maglev train and not have to worry about rockets at all.

You would have to do at least a circulization burn no matter the budget spent on maglev.

You can do that but it would require a track that is tens of kilometers long along with a magnetic levitation technology. My suggestion is something we can do right now with a basic landing strip. But yes a meglev is the end game. Needs to reach 8,570 km/h for moon orbital velocity.

That is the idea behind "mass drivers" on the moon I believe. Maybe that search term helps.

Then when the inevitable war for independence takes place, you have the option to throw rocks at Earth. ;)

> lowers how much propellant you need to bring to the moon by a lot

Rough estimates? Mass drivers make sense. I haven’t seen the numbers for just compressing and leveling regolith.

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