"Exactly how fast do you think this thing needs to be?"
You get a lot of frictional losses from the atmosphere during the initial boost phase. I want to end up at orbital and sub-orbital speed.
If possible, I want to be able to go single-shot to interplanetary. That's an after atmosphere speed of seven miles per second, or over 25000 miles per hour.
I'd probably need to exit the launcher at Mach 40.
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