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. No other "surface" transportation anywhere even approaches this speed. Yet
it is an utterly comfortable ride-three minutes that feel like lying in a
hammock on Terra, then twelve and a half minutes of weightlessness, and again
three minutes in that garden hammock. How can you beat that?
Oh, you could do it faster by accelerating at multiple gee. But not much.
If your acceleration could be instantaneous (killing all passengers!) and you
decelerated the same way (splat!), you could raise your average speed to just
over six thousand kilometers per hour and trim your time back by almost three
minutes! But that's the ultimate.
That is also the best possible time for a rocketship between Kong and
L-City. In practice a jumpbug rocket will usually take about half an
hour-depends on how high its trajectory is.
But surely a half hour is short enough. Why tunnel under maria and
mountains when a rocket can do the job?
A rocket is the most lavishly expensive transportation ever invented. In a
typical rocketship mission half the effort is spent fighting gravity to go up
and the other half is spent fighting gravity in letting down-as crashing is
considered an unsatisfactory end to a mission. The giant catapults on Luna, on
Terra, on Mars, and in space are giant statements against the wastefulness of
rocket engines.
Contrariwise, the ballistic subway is the most economical transportation
ever devised: No mass is burned up or thrown away and the energy used in
speeding up is given back at the other end in slowing down
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