Dr. Charles Elachi, JPL Director and Dr. Jonas Zmuidzinas, JPL Chief Technologist.
MDL News & Trends
Letter from Dr. Charles Elachi, JPL Director and Dr. Jonas Zmuidzinas, JPL Chief Technologist Celebrating Two Major Milestones at JPL
This year, JPL celebrates two major milestones: the 50th anniversary of Mariner 4’s flyby of Mars—the first ever—and the 25th anniversary of our Microdevices Laboratory (MDL). Surprisingly, there is a connection. In a recent article, Caltech professor Yuk Yung describes the scientific impact of the in situ detection of methane on Mars by the Curiosity rover: “If it is borne out, this discovery becomes one of the greatest Eureka moments in the half century of robotic exploration of Mars, beginning with the first success of Mariner 4 in 1965…” The detection was reported by MDL Director Chris Webster in a 2015 paper published in Science, and was enabled by a tunable infrared laser developed and produced at MDL by the group led by MDL Deputy Director Siamak Forouhar.
As with many triumphs in science, there is a long history. The basic technique of tunable infrared laser spectroscopy is almost as old as Mariner 4, and even before Mariner 4’s Mars flyby, Carl Sagan was interested in the use of infrared spectroscopy to look for molecules in the Martian atmosphere. Thus, the scientific opportunity was apparent quite early but the technological and engineering challenges were daunting. The Mariner 4 radio science experiment told us the pressure of the Martian atmosphere and therefore the severe difficulty of landing, which prompted a host of clever solutions involving heat shields, parachutes, airbags, and ultimately Curiosity’s skycrane, which amazed us all on the evening of August 6, 2012. Yet the task of making an infrared laser suitable for Mars was no less challenging—the starting point was a device cooled by liquid helium in a meter-sized cryostat.
A major breakthrough was Rui Yang’s 1995 invention of a new concept, the interband cascade laser (ICL), which uses an ingenious, complex, layered semiconductor structure to boost efficiency and reach much higher operating temperatures. Yang came to JPL/MDL to develop ICLs for Mars and received the 2007 Ed Stone Award for his work before joining the faculty at the University of Oklahoma. Today, room-temperature ICLs are being commercialized for detecting gas leaks and for in situ measurements of greenhouse gases.
This long history—25 years of work at MDL and 50 years of robotic exploration of Mars—serves to emphasize the difficulty of the challenges we undertake. Indeed, as John F. Kennedy said in his famous 1962 speech, we choose to do these things “not because they are easy, but because they are hard.” We seek out important challenges for which there is a significant risk of failure, a risk of being seriously disappointed after a decade or more of very hard work. Yet we persist, because the challenges and the goals we pursue invigorate and motivate us in ways that lesser challenges would not.
— Dr. Charles Elachi, JPL Director / Dr. Jonas Zmuidzinas, JPL Chief Technologist