Dr. Edward C. Stone's Contributions to Aerospace

Dr. Edward C. Stone  
January 23, 1936 – June 9, 2024 

On June 9, 2024, Edward C. Stone, PhD, an American space scientist and former director of the NASA-Caltech Jet Propulsion Laboratory, passed away at age 88. Stone’s long and distinguished career in space science connects to many of the planetary exploration objects displayed in the galleries at the Smithsonian’s National Air and Space Museum. That so many of the Museum’s objects have connections to his professional achievements illustrates Stone’s significant legacy in space science and exploration.

Corona

When Stone entered graduate school at the University of Chicago in the early 1960s, his first project involved designing science instruments to measure the solar wind as part of the U.S. Air Force and Central Intelligence Agency’s Discoverer satellite program, later known as the CORONA program. The program involved launching cameras and instruments into space on clandestine reconnaissance satellites. The cameras used film, and the film was returned in capsules that fell through the atmosphere to be collected by airplanes. The Museum holds multiple components of the CORONA program, including a reentry capsule from the last CORONA mission and a KH-4B camera system . Stone’s instrument flew onboard Discoverer 36/CORONA 9029, which launched in 1961, which was a KH-3 CORONA satellite.

Orbiting Geophysical Observatory

When Stone graduated with his Ph.D., he followed his senior University of Chicago colleague Rochus (Robbie) Vogt to Caltech in Pasadena, California. As a postdoctoral fellow, Stone helped Vogt found a new Space Radiation Lab and focused his research on the study of galactic cosmic rays. He became involved in NASA’s Orbiting Geophysical Observatory (OGO) program, a series of 6 scientific satellites launched by the United States from 1964-1969. After becoming a full faculty member at Caltech in 1967, Stone was the Principal Investigator of the Cosmic Ray Experiment on OGO-VI. The OGO-VI satellite was the last launch of the OGO program. The Museum holds several instruments and experiments from the OGO program, including a flight spare of the Plasma Wave Detector from OGO-V. 

Interplanetary Monitoring Platform

At Caltech, Stone also contributed to NASA’s Interplanetary Monitoring Program (IMP). This consisted of a series of Interplanetary Monitoring Platform satellites intended to study cosmic rays, solar wind, and magnetic fields beyond that of the Earth, in order to better understand the interplanetary medium in which spacecraft operate and through which Apollo astronauts travelled. Stone was the Principal Investigator of the Electrons and Hydrogen and Helium Isotopes experiment on IMP-7 (also known as IMP-H or Explorer 47), which launched in 1972. The Museum holds an engineering model of IMP-A  (or Explorer 18), the first in the IMP series, launched in 1963.

 Voyager

The same year IMP-7 launched, the Jet Propulsion Laboratory offered Stone the position of Project Scientist on the Voyager mission that would launch twin spacecraft to explore the outer solar system. In this position, Stone led 11 different instrument teams.  When he took leadership of the mission, they had five years to prepare the teams and instruments for launch in 1977. 

The Voyager program was an incredible success, sending back images and data from Jupiter, Saturn, Uranus, Neptune, and their moons and rings. The two spacecraft still continue their journeys today, beyond the limits of our solar system. The Voyager Development Test Model  on display in the Museum’s Kenneth C. Griffin Exploring the Planets Gallery is one of the largest spacecraft that the Museum has ever collected (with the magnetometer boom fully extended, it is 42.7 feet/13 meters long). Donated shortly after the two spacecraft left Earth, it was also one of the first planetary spacecraft ever displayed at the Museum.

Mars Pathfinder & Sojourner

In 1991, Stone became director of the Jet Propulsion Laboratory. He served in this role for the next 10 years, and oversaw the development, launch, and operation of multiple missions. These included the landing of Pathfinder and the first rover, Sojourner, on Mars. The Museum displays Sojourner’s flight spare, Marie Curie, in the Exploring the Planets Gallery. 

Sojourner demonstrated the potential scientific return of robotic mobility on Mars. It has been followed by larger and better instrumented rovers such as the Mars Exploration Rovers Spirit and Opportunity; the Mars Science Laboratory rover Curiosity, and the Mars 2020 rover Perseverance. Sojourner’s successful demonstration of new technology on Mars in 1997 is echoed in the recent success of the Ingenuity Mars helicopter. The Museum displays in its two facilities a testbed version of Spirit and Opportunity, a display model of Curiosity, and a recently acquired prototype of the Mars helicopter Ingenuity.

Curators want the Museum’s visitors to understand that every spacecraft they see on display was designed, conceived, built, launched, and operated by people. Ed Stone personally had a hand in some of the most significant and impactful programs in the space age. As the planetary science community mourns his loss, the objects at the Museum will continue to tell his story.