QUESTION:
How much power does it take to send the signal from Antarctica to us?


        David D., fifth grade
        Ms. Landmann's Class
        Rio del Mar Elementary
        Aptos, CA

ANSWER from Annie Devereaux, NASA ACTS Satellite Team
            Palmer Station, Antarctica
            Fri, 14 Feb 1997 13:34:04 -0300

Dear David,

We actually have a fairly small power source here, only 10 Watts.  You
can compare this to a 60 Watt light bulb that you may have in your
bedside lamp.  Why we can get away with such little power is that we
brought with us a big antenna, which you can see a few times during the
TV programs.  Rather than allowing the 10 Watts to radiate in all
directions, like your light bulb, the antenna focusses the power into
one narrow beam, like a flashlight.  The effect of this focussing
magnifies the 10 Watt input power to the equivalent of 1 million Watts. 
A pretty good sized flashlight, but then, the ACTS satellite is also
very far away from us here at Palmer-- about 22,000 miles away.

Thanks for your great question!

Annie