How do you talk to someone on the other side of the planet?

At the dawn of civilization, one might dispatch messengers via horseback (or fast runner in the Western Hemisphere, horses being unknown until the Conquistadores came).  That might take months or even years.  Smoke signals and heliographs were a little better, but they still were limited to line of sight transmission. 

The telegraph was a revolution.  Now, messages could travel from point to point at the speed of light.  A few decades later, telephones enabled live conversations at great distance.  Radio broadcasts shrunk the world further, broadcasting messages wirelessly throughout the globe.

But neither the telephone nor radio are perfect solutions to the presented problem.  With telephones, both parties need to be physically connected to each other.  Radio is notoriously unreliable at great distances.  Things are worse if you're in the military–neither phones nor the wireless are secure: wires can be tapped, and radio is broadcast in the clear.

What you really want is a tight-beam radio broadcast, one that could be directed at any recipient without need for wires.  But for that, you'd need a series of repeating towers that provide service anywhere on Earth.  That's a tall order.  Not only is it expensive, but pesky oceans get in the way.  You could get away with fewer towers if they were tall enough, but how do you construct a 100-mile high repeating tower?

Easy.  You build just the top of the tower–and launch it into orbit, where it can be overhead indefinitely.  And that's just what the U.S. Army Signal Corps did yesterday (October 4) with its brand-new communications satellite, aptly dubbed "Courier." 

Courier is a revolution.  Where Project Score, launched two years ago, merely sent a pre-recorded message, and NASA's recent Project Echo only reflects signals off of its balloon surface, Courier is an "active repeater."  This means it can receive messages from a transmitter, then wait until the recipient is in sight to deliver them.  It's secure…and fast.  Courier can relay 68,000 words per minute, enough to send an entire King James Bible in 11 minutes!  And all one needs is a receiver that can hear the frequencies on which Courier transmits.

Yesterday's launch was actually the second time the Army tried to launch a Courier; the first attempt on August 18 ended prematurely thanks to a balky Thor Able-Star booster.  But the current mission is a complete success; the 500 pound, 51-inch wide sphere has already been used to send a message from the President (at Fort Monmouth, New Jersey) to Secretary of State Christian A. Herter (at the United Nations, by way of Salinas, Puerto Rico). 

We've come a long way in the three years since Sputniks, with triumphs ranging from moon probes to weather satellites to space dogs.  The next three years will be even more exciting: manned orbital shots, probes to Venus and Mars, space telescopes, commercial communications satellites…and who knows what else!