ISLAND ONE, a prime time family sitcom set on the High Frontier

--- In spacesettlers, "Dan Wylie-Sears" wrote:

> Equator is good, of course. But why an island?

An island means that not only can you launch due east from the
equator, but you can do it over open ocean. This is important
because when that shuttlecraft come booming out of the acceleration
tunnel at close to Mach 3 it's really going to be BOOMING. I'd
imagine that there are only so many good equatorial coasts available.

> Every meter of altitude decreases the delta-vee you need, and when
> you're paying the rocket equation every bit counts. Plus, the
> first meter of air at sea level has a lot more drag than the first
> meter of air you encounter if you're starting from a kilometer or
> two above sea level.

A five hundred metre high support stucture seemed a reasonable thing
to have sticking up out of the ocean. If based on a contenent, even
if it is a sea level beach, I'd've gone for a full kilometre high.

>> The important thing here is that NOTHING IS THROWN AWAY (even the
>> ET's descendant is used over and over again)

> While building colonies, I would be more inclined to have the fuel
> tanks be material that can be used in orbit.

This *is* a lot cheaper than sending it up as "regular" payload. I'm
assuming that by the time Island One is under construction, we are
getting enough material from the Moon and/or asteroids that the extra
fifty tons or so of tank material isn't enough valuable enough to
offset the expense of building a new tank stage for every launch.
Certainly I hope to see ET's used as both raw materials and as ready-
made pressure hulls, but in the earlier stages.

>> The acceleration tunnel starts a hundred metres or more
>> underground, and the shuttlecraft travels in a circle all the way
>> around the circumference of this island

> When you're dealing with circles, the equation to keep in mind is
> a = v^2/r. You can go around a circle as many times as you feel
> like to build up speed if you have a payload that's sensitive to
> acceleration, but it's going to be exposed to the centripetal
> acceleration to keep it curving around the circle. If your limit
> is 3g and your radius is 2.5 km, that gives
>
> 30 m/s^2 = v^2/2500m
>
> 30*2500 (m/s)^2 = v^2
>
> v = ~273 m/s
>
> I haven't plugged that in as u in the equation ANTIcarrot supplied,
> but it sounds like the straight part is going to have to be a bit
> longer.

Well, with the good news I got on that (I don't need 16 km [10
miles], 10.6 km [6.6 miles] is enough), I'm considering making
the "business end" of the acceleration tunnel one km long and angled
at 45, the shuttlecraft exiting one km high, with the other end two
kilometres under ground and oh so gradually curving from level to
that 45 angle. Total length: seven km. Maybe I'll even make the
whole thing 45, with 3.5 km underground and the exit point 3.5 km
high. Or maybe not. Maybe the big circle is better after all.

Of course Mike Combs' Sky Bridge would be even better, and a full-on
space elevator even better than that. I see this as a step between a
purely rocket-based launch system and Sky Bridge.