Re: starship-design: Re: Into detail

[KellySt@aol.com]

In a message dated 7/7/97 7:35:49 AM, TLG.van.der.Linden@tip.nl (Timothy van
der Linden) wrote:

>Kelly,
>
>>>Well a factor 2 bigger 300,000 miles instead of 3,000 miles will resolve
>>>objects of:
>>>
>>>d=1.22 * 9.45E16 * 5.3E-7 / 5.556E8 = 110 metres
>>
>>Not bad over interstellar distences.  If you see anything really
interesting
>>you could probably get funding to scale up the scope array.  A 4 order of
>>magnitude improvement should get you 1 meter res.  8 order centimeter rest.
>> Enough to study life forms (if any).
>>
>>Expensive, but not compared to the starship project.
>
>Resolution power doesn't seem to be the biggest problem, it "merely" needs a
>few small telescopes that are far apart.
>More essential is the brightness problem for which we would need really huge
>telescopes that can be more expensive that a starship project.
>
>>>We make a 1 second photograph. (Can't do longer, otherwise the planet has
>>>turned much more than 110 meters)
>>
>>The scope aray or post processors could compensate for the rotation.
>
>Yes, that might work. so you may indeed decrease the telescope size a bit if
>you can make longer exposures.
>
>>>Therfore we need an aperture surface of 1E6*6.6E8=6.6E14 square meters.
>>>
>>>Hmmm, that means a aperture radius of 14.5 kilometers. Most of my
estimates
>>>have been quite optimistic, so it could well be that one needs a few
orders
>>>bigger. 
>>
>>Ah, I make that 2.5e7 meters per side.  How'd you get 14,500?
>
>I used a circular aperture, but also accidentally devided by 1E6 instead of
>1E3 to get kilometers. The mistake was mine, so the aperture radius has to
>be 1000 times bigger. Not a trivial upscale!
>
>Regarding resolving 1 meter details, I'd rather not think about that
>anymore. Multiple exploring missions would be cheaper and easier to do.
>
>Timothy

Given the tens to hundreds of billions of dollars even one of these mission
would probably take.  I seriously doubt that a meter res scope would be more
costly.

Kelly