Re: Asteroid mining question

Mike Williams wrote:

> Wasn't it Jack Tingle who wrote:
> 
>> I was never sure where that came from. Relatively easy on a 
>> per-pound-of -asteroid basis, and relatively easy period are not the 
>> same thing. We can currently handle things around the earth on the 
>> order (optimistically) of a hundred tons. (Skylab was 77 tons. Yes, I 
>> know ... ISS is bigger ... no more Saturn V's ... shuttle is almost 
>> shot ... make it in pieces ... shuttle derived big boosters ... 
>> yadayadayda ... Bugger that. A hundred tons.)
> 
> But getting a hundred tons into low Earth orbit is a completely 
> different prospect to getting a hundred tons from the asteroid belt into

> Earth orbit.
> 
> Probes that we've sent to the asteroid belt and beyond have had to use 
> at least one gravity assist swingby to achieve the required velocity. 
> Since there's no friction in space, reducing the velocity would need to 
> use the same trick. Note that each swingby adds something like a year to

> the duration of the trip.

They're different prospects, but they're not _completely_ different. 
Going from the surface of the Earth to low Earth orbit is far harder (in 
deltavee and stress) than going from low Earth orbit to the asteroid belt.

-- 
Erik Max Francis && max@[EMAIL PROTECTED]
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