Published in Joe 90 Top Secret #14, 04/19/1969 - cover and 3 pages.
"Joe 90 ... Rocket Expert" Saltmarsh is the site of the Pan European Rocketry Research Station and it is there that scientists are preparing the launch of Probe Alpha. It is the first rocket to be completely programmed and fired by computer, working on radio signals keyed to a secret wavelength known only to the scientists. Now something is jamming the signals and someone else is controlling the rocket.