Subject: Distance to Moon & Planets in Miles: Nautical or Regular?

As an Amateur Astronomer I've wondered why during space flights,say Apollo or 
Space Shuttle, measurement is given in nautical miles. But when we read say 
Mars is came to within 35 Million Miles as of August 27, 2003 we say Miles not 
Nautical. In a recent Sky & Telescope article, I noticed the term 
"International Miles".

Can you clarify this for me?

I would just like to know the definitions so when I speak with non-astronomers 
I can be quite sure I have the right information.

A secondary question is why we measure the distance between center of one 
planet to the center of another? Don't you have to make corrections if you are 
landing say on the Moon or Mars?

Wouldn't you want to say surface to surface when you are talking to the public?

Thanks so much!

P. Edward Murray
Past President,
Bucks-Mont. Astronomical Assoc., Inc.

Re: Distance to Moon & Planets in Miles: Nautical or Regular?