In 1957, as I drove to the University of Chicago for the Fall term of physics classes, I remember seeing a newspaper headline announcing that Russia had launched a spacecraft into earth orbit.  Sputnik 1 transmitted a radio signal as it circled Earth, marking the beginning of the Space Age and a new realm of human activity.

That journey began in my hometown of Burlington, Iowa, on the banks of the Mississippi River.  I was the older of two sons in a family of four.  Our father was a construction superintendent who enjoyed learning new things and explaining how they worked.  As a homemaker, our mother created a warm, welcoming, and nurturing space for our family.  Both parents had a strong work ethic, and later our mother served as the business manager for the Overhead Door franchise our father had acquired.

They encouraged my pursuit of scientific and technical activities such as building radios and other electronics.  My physics teacher further advanced my scientific and laboratory experience and it was due to his urging that I enrolled at the University of Chicago in October of 1956, one year before the surprising launch of Sputnik 1 by the Soviet Union.

I was fortunate to have had Professor John A Simpson as an advisor.  In the summer of 1958, I began working in his group, and in December 1961, my thesis experiment, a cosmic ray telescope, was launched into a polar orbit on Explorer 36. Though the data were limited, this was my first step in measuring cosmic rays from supernova explosions and solar energetic particles produced by solar eruptions.

After completing my thesis in 1964, I joined Professor Rochus Vogt, a former fellow Chicago graduate student, in establishing a space physics programme at Caltech in Pasadena, California.  Since then I have had a leading role in developing instruments for determining the composition of cosmic rays and solar particles and have been the principal investigator or co-investigator on fifteen NASA spacecraft, five of which are still operating.

In 1965, the fledgling field of space exploration expanded to the outer solar system and beyond.   A student at the Jet Propulsion Laboratory, managed by Caltech for NASA, discovered that a spacecraft launched in 1977 could swing by Jupiter, Saturn, Uranus, and Neptune.  This “Grand Tour” alignment occurs only every 176 years, so NASA took the bold step of developing two identical spacecraft, called Voyager 1 and 2, to undertake the journey.

As the Voyager Project Scientist, I coordinated eleven teams of scientists selected by NASA to study the planets, their satellites, rings, and magnetic fields. Only five of the teams continued beyond Neptune as the focus for the two spacecraft shifted to the much longer journey to interstellar space.

During these years, I have also had opportunities to contribute to other observatories.  In 1983, two years after the Voyager 2 encounter with Saturn, I became chair of the Division of Physics, Mathematics, and Astronomy at Caltech, and oversaw the construction of the W M Keck Observatory that has two telescopes with ten-meter mirrors that peer deep into space from atop Mauna Kea on Hawaii Island.

Not all observatories have telescopes designed for observing light waves, and in 1987, I oversaw the establishment of LIGO, the Laser Interferometer Gravitational-Wave Observatory.  Nearly three decades later, its laser system detected the first gravitational waves from the merger of two black holes.

Two years after Voyager’s flyby of Neptune in 1989, I became JPL Director, serving from 1991 to 2001.  JPL celebrated a number of memorable missions during this time, including:  a plucky little Mars rover; the Galileo spacecraft that orbited giant Jupiter for eight years; Cassini, a spacecraft that dropped a probe into the atmosphere of Saturn’s moon Titan and orbited the planet itself for thirteen years; and the Wide Field/Planetary Camera, constructed at JPL, for NASA’s Hubble Space Telescope.

After retiring as JPL director, the development of the Thirty Meter Telescope (TMT), beckoned.  With a mirror thirty meters across, TMT will collect enough light from the distant universe to study the first generation of stars and to search for evidence of life on planets orbiting nearby stars. As the founding executive director of the TMT International Observatory, I oversee a consortium of scientists and engineers from Canada, China, India, Japan, Caltech, and the University of California, that looks forward to first light from the top of Mauna in 2030.

The journey that began in Burlington, Iowa, reached two major milestones in 2012.  My wife, Alice, and I celebrated our 50th wedding anniversary with family and friends in Burlington just as Voyager 1 became the first human-made object to enter interstellar space.  Joined last year by Voyager 2, the two spacecraft will be Earth’s ambassadors to the stars, orbiting the Milky Way for billions of years.

25 September 2019   Hong Kong