Deep Space and Ham Radio

On August 5, 2011, NASA launched the Juno mission to Jupiter.  The spacecraft is following a low energy trajectory; it was initially launched into an orbit that won't allow it to escape and go to Jupiter.  It had to do an Earth flyby so that it could be given a bit more speed, a gravitational slingshot, which it accomplished on October 9, 2013.  The maneuver allowed the satellite to pick up an additional 8,800 MPH and set it on path to a July 4, 2016 arrival at Jupiter.

Juno’s launch vehicle was capable of giving the spacecraft only enough energy to reach the asteroid belt, at which point the sun’s gravity pulled it back toward the inner solar system. Mission planners designed the swing by Earth as a gravity assist to increase the spacecraft’s speed relative to the sun, so that it could reach Jupiter. (The spacecraft’s speed relative to Earth before and after the flyby is unchanged.)

Juno is carrying a radio receiver called the Waves receiver; the receiver tunes more than the entire HF (shortwave) radio spectrum; from 3 to 40 MHz for monitoring natural radio emissions from the giant planet.  The lead engineer on the project, Don Kirchner, had an idea for an interesting way to test that receiver.  Don is a radio amateur - a ham, KD0L, and immediately realized that the receiver tunes across all the HF amateur bands, but that one of them offered good conditions for a test of the receiver.  If he could only get hams all around the world to send very slow, synchronized Morse code to the satellite in the 10 meter (28-29.6 MHz) band.

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Techy details here.