QUESTION:
How fast does the hubble send data?

ANSWER from Peter Mangiafico on May 28, 1996: 
I must admit, I didn't know this question myself...after a bit of searching 
via the World Wide Web, I came up with the following data, which you can 
learn more about if you have internet access by looking at:

http://nssdc.gsfc.nasa.gov/cgi-bin/database/www-nmc?90-037B

The Hubble Space Telescope (HST) uses the TDRSS for communication.  
TDRSS stands for "Tracking and Data Relay Satellite System", which is a 
dual-satellite link between the Earth and the telescope.  This provides for 
access to the telescope even if it is on the other side of the Earth (from 
the Goddard Space Flight Center, in Greenbelt, MD, from where the 
telescope is controlled).  Since HST is in low-Earth orbit, it spends a 
small portion of its orbit out of range of either TDRS, and thus HST also 
has tape recorders so that data can be stored and transmitted later.    

To answer your question, HST technically "sends data" at the speed of light, 
since this is how fast electromagnetic radiation, such as radio waves, 
travel in empty space.  This information moves with a limitied "bandwidth" 
however, which means that only so much information can move at once.  
You can think of it like car travel:  a car can move at 65 MPH, but only 
so many cars can move at that speed on a highway before a traffic jam 
occurs.  The more lanes you have on your highway, the greater the 
"bandwidth", and the more cars can move comfortably at 65 MPH.  
The data bandwidth (analogous to number of lanes) is given in kpbs, which 
stands for "kilo-bits-per-second" or thousands of bits per second.  
A bit is a single piece of computer data.  Eight bits equal one byte and 
one byte is the amount of information necessary to store one letter 
(such as the letter "a"). While the bandwidth varies greatly, the top 
rate is around 1000 kbps, which is about 125,000 bytes per second.  
In computer terms, this is about 125K (1 K = 1024 bytes) per second.  
For reference, this entire answer takes about 2K (or 2000 bytes, or 
16000 bits) of computer space.  That might seem pretty quick, but 
astronomical images take up lots of computer space!