More BASICS on space flight (was Re: SPACE: Roton in New Scientist)

Michael Butler (
Sat, 8 Aug 1998 02:57:56 -0700 (PDT)

This is also extremely basic stuff.

The spacecraft is already "just kinda" in free fall.

A ballistic object moving sideways at a speed at or above five miles a second never hits the earth because the Earth's surface "falls" at at least the same rate the object does (no fair pointing the object so it hits).

Every gram of propellant you orbit has to be accelerated to 5 or more miles a second. That's expensive. Remember $10,000 a pound? And then, 5 miles a second of of delta vee would necessitate a very large amount of propellant having been orbited per gram of ship returned. Somebody (Michael?) work the numbers here--I'm too tired.

If you have a beanstalk, you can get to orbit for not much more than the cost of electricity; and you can go up or down as slowly as you please. Good luck building the beanstalk.


On Fri, 7 Aug 1998 wrote:

> It seems a major thing about space travel is the high temperature re-entry.
> Why not not slow the craft down before re-entry? like before we re-enter, use
> a saved amount of fuel and blast in the opposite direction, and just kinna
> free-fall back into earth.
> danny