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Re: Re: Re: Re: starship-design: Re: Perihelion Maneuver

KellySt@aol.com wrote:
>In a message dated 11/27/97 3:09:43 AM, kuo@bit.csc.lsu.edu wrote:

>>That is a big deal!  Do you have any idea how to do VLBI with
>>visible wavelengths?

>>If so, there's a Nobel Prize waiting for you.

>>We can do VLBI with microwave wavelengths because it's just barely
>>possible to measure phase with them (and thus possible to receive
>>multiple signals and constructively interfere them appropriately).

>>We _can't_ do VLBI with infrared and shorter wavelengths.  It _might_
>>be possible to do it in the future, but don't bank on it.

>Actualy we do currently do VLBI with optical ground telescopes, and NASA is
>tinkering with a project to scatter 1 meter drone scopes across an area of
>hundreds of miles of lunar surface.

We do LBI with optical ground telescopes.  So far as I know, VLBI is
impossible with known technology.

The V in VLBI stands for "Very".  What that means is that the elements
are so far apart that they aren't rigidly locked wrt to each other
within the tolerance of about 1/4 the working wavelength.

The moon's surface provides a very stable nearly rigid "structure"
to lock a bunch of elements wrt to each other, but this isn't necessary
with VLBI.

>>>>> Or funding sources that much more patent?  If it take a half
>>>>>century to get results, a inteligent person will wait a couple
>>>>>decades for faster cheaper systems.

>>>>Not if those "faster cheaper" systems aren't going to be much faster or
>>>>much cheaper.

>>>When have we not developed much better systems after a few decades?

>>For instance, automobiles.  Automotive technology has gotten a bit
>>better, but a 1960's Cobra can race competetively with anything
>>we can build today of similar weight/size.  A 1940's Volkswagon
>>is still one of the most fuel efficient vehicles you can drive.

>>Cars are a bit better, but not outrageously better, than several
>>decades ago.

>Cars speeds are governed by highway speed limits.

Not on the racetrack.

>Unrestricted the max speed
>for a car a hundred years ago was tens of miles per hour, just recently
>supersonics (700+) were runing.

Not on the racetrack.

Admittedly there was a vast improvement in automotive technology
between 100 and 50 years ago.  However, since then improvement
has largely leveled off.

>Oh and gas milage and the rest for cars a decade or so old are fairly bad by
>current standards.  (Top fuel efficent cars from the dealership can get up to
>100 mpg, thou few are very drivable.)

Anyone knows that car fuel efficiency depends upon the car's
size/weight.  Comparing cars of equivalent size/weight, we haven't
improved gas mileage much.

Well, since you seem unconvinced by what I deemed a blatant example,
I'll give another--small arms.  Today's military small arms don't
significantly outperform those from 40 or 50 years ago except in
improved reliability.
    _____     Isaac Kuo kuo@bit.csc.lsu.edu http://www.csc.lsu.edu/~kuo
/___________\ "Mari-san...  Yokatta...
\=\)-----(/=/  ...Yokatta go-buji de..." - Karigari Hiroshi