Les Johnson

Les Johnson

Les Johnson


Deputy Manager for NASA's Advanced Concepts Office Marshall Space Flight Center in Huntsville, Alabama

Tuesday  April 24, 2012  12pm
Chester F. Carlson Center for Imaging Science Auditorium

Solar Sailing: Using Solar Photon Pressure for Exploring the Solar System and Beyond


Solar sail propulsion uses sunlight to propel vehicles through space by reflecting solar photons from a large, mirror-like sail made of a lightweight, highly reflective material. The continuous photonic pressure provides propellantless thrust to perform a wide range of advanced maneuvers, such as to hover indefinitely at points in space, or conduct orbital plane changes more efficiently than conventional chemical propulsion. Eventually, a solar sail propulsion system could propel a space vehicle to tremendous speeds—theoretically much faster than any present-day propulsion system. Since the Sun supplies the necessary propulsive energy solar sails require no onboard propellant, thereby significantly increasing useful payload mass.

Practical concepts for solar sailing have existed for approximately 100 years, beginning with Tsiolkovsky and Tsander in the 1920s. A team at JPL completed the first serious mission study in the late 1970s for a rendezvous with Halley’s Comet.  In the early-to-mid 2000’s,  NASA’s In-Space Propulsion Technology Project  made substantial progress in the development of solar sail propulsion systems. Two different 20-m solar sail systems were produced and successfully completed functional vacuum testing in the Glenn Research Center’s (GRC’s) Space Power Facility at Plum Brook Station, Ohio.  Solar sail propulsion was recently selected for space demonstation by NASA’s Technology Demonstration Program with flight planned for 2014.

Outside of NASA, solar sailing has been tested in space.  In the summer of 2010, the Japanese Aerospace Exploration Agency, JAXA, launched a solar sail spacecraft named IKAROS in tandem with another mission to Venus. The sailcraft IKAROS (14 m by 14 m) is the first in-flight demonstration of solar sailing.  While the effects of solar radiation pressure (SRP) are smaller on this sailcraft as compared to other concepts for solar sails, numerous program objectives have been achieved, including verifying solar radiation pressure (SRP) effects on the sail and performing in-flight guidance and navigation techniques using the solar sail. 

This talk will discuss the fundamental physics of solar sail propulsion, review technology progress to-date, and provide an overview of the future application of solar sails for deep space exploration.



Les Johnson is the Deputy Manager for NASA’s Advanced Concepts Office at the Marshall Space Flight Center in Huntsville, Alabama.  He is a co-investigator for the JAXA T-Rex Space Tether Experiment and was PI of NASA’s ProSEDS Experiment.  During his career at NASA, he served as the Manager for the Space Science Programs and Projects Office, the In-Space Propulsion Technology Program (including solar sail propulsion), and the Interstellar Propulsion Research Project.  He twice received NASA’s Exceptional Achievement Medal and has 3 patents.

He earned his Master’s Degree in physics from Vanderbilt University (Nashville, TN) and his BA at Transylvania University (Lexington, KY).  He participated in the ISU 1993 Summer Session Program in Toulouse, France.  Les has numerous peer reviewed publications and was published in Analog.  He is a frequent contributor to the Journal of the British Interplanetary Society and a member of the American Institute of Aeronautics and Astronautics, the National Space Society, the World Future Society, and MENSA.

He is an author of three popular science books, “Living Off the Land in Space,” “Solar Sailing: A Novel Approach to Interplanetary Travel,” and “Paradise Regained: The Regreening of Earth.”  His first science fiction novel, “Back to the Moon,” was published in December 2010.

book signing at 1:00pm

Back to the Moon by Travis S. Taylor and Les Johnson (Dec 27, 2011)

Going Interstellar by Les Johnson and Jack McDevitt (May 29, 2012)

Living Off the Land in Space: Green Roads to the Cosmos by Gregory L. Matloff,Les Johnson and C. Bangs (Jun 6, 2007)

Paradise Regained: The Regreening of Earth by Les Johnson, Gregory L. Matloff and C Bangs (Dec 11, 2009)

Solar Sails: A Novel Approach to Interplanetary Travel by Giovanni Vulpetti, Les Johnson and Gregory L. Matloff (Dec 1, 2010)