ASHLAND — A 1980 Paul G. Blazer High School graduate has co-authored a book that could help take space travel a step forward while saving untold millions on dollars.

Les Johnson, deputy manager of the advanced concepts office at the George C. Marshall Space Flight Center in Huntsville, Ala., with Giovanni Vulpetti and Gregory L. Matloff, wrote “Solar Sails: A Novel Approach to Interplanetary Travel.”

Solar sails are very thin structures — yards or miles wide — made of reflective material propelled through space by the reflection of sunlight, Johnson said. Photos, or particles of light, are without mass but do have momentum. They reflect from a massive lightweight sail — a solar sail — and transfer their momentum to the sail, causing it to move.

“Think of what happens when you throw a ball at a partially open door,” Johnson said. “The ball bounces off the door, and the door recoils in the opposite direction. If you substitute photons for the ball, and the solar sail for the door, then you will understand how a solar sail moves through space.”

It’s fact and fiction

Solar sail technology might sound like science fiction. In fact, there have been references to solar sails in various sci-fi works, including “The Wind from the Sun” by Sir Arthur C. Clarke and one of the more recent Star Wars movies.

However, Johnson points out solar sails are beyond the theoretical stage, having been used in practical ways in many instances of the years:

‰In 1873, James Clerk Maxwell first demonstrated that sunlight exerts a small amount of pressure as photons bounce off a reflective surface; this is the basis of modern solar sail design.

‰In 1960, the communications satellite Echo-1 was battered about my solar pressure. NASA’s Web site states, “The shards were flug far and wide by sunlight.”

‰In 1974, when Mariner 10 ran low on attitude control gas, the craft’s solar arrays were angled into the sun so solar radiation pressure could be used and it was used successfully.

‰Solar sails were an accessory on India’s INSAT 2A and 3A communications satellites in 1992 and 2003. The satellites were powered by a four-panel solar array on one side. A solar sail was mounted on the north side of each satellite to offset the torque resulting from solar pressure on the array.

“Unfortunately, due to lack of funding, we are not yet flying them in space,” he said.

Saving fuel

Solar sails work only in space, so Johnson explained there is no practical use for them on earth. But the benefits in space are huge.

“Their primary benefit over rockets is that they use no fuel. Since launching anything into space costs a lot of money ($7000 to $10,000 per pound), a solar sail propulsion system cannot only save on the cost of fuel, but also the cost of launching the fuel,” Johnson said.

The book has been well received by the scientific community. Johnson said Nature, the top science journal, gave it a good review and put it on their recommended reading list.

“I never thought I would be published in Nature,” he said. “This was definitely a high point in my career.”

Future plans

Johnson graduated from Transylvania University in Lexington with a degree in chemistry and physics in 1984 and earned a master’s degree in physics at Vanderbilt University.

His first book, “Living Off the Land in Space,” was written with Gregory Matloff and C Bangs. The book about solar sails was requested by his publisher; the authors collaborated entirely through the Internet and e-mail. Johnson is the lead author on the book “Paradise Regained,” which is due to be published late this year.

Johnson also dabbles in science fiction: he’s signed a contract to write a novel that will be published in 2010.

In addition, Johnson is the co-investigator for a Japanese tether propulsion experiment that will fly next summer from Japan.

“I consider myself to be a very lucky man,” he said. “I’m working in my dream job.”

Although Johnson has no close family left in Ashland, he said he comes back to visit every couple of years and tries to make the reunion of the “kids of Lynnhaven” every four years.

“I also have a dear friend in Ashland whom I consider to be like an aunt. Miss Jo Howard was the co-owner and manager of The Book Rack and gave me a job there when I was in high school,” he recalled.

“I see Jo every time I am in town and I consider her to be one of the most influential people in my life, outside of immediate family. I could write a book about our adventures at The Book Rack — in fact, I probably will someday!”



For more information about solar sails, visit science.nasa.gov/headlines/y2008/31jul_solarsails.htm. For more information about Les Johnson, visit lesjohnsonauthor.com.





LEE WARD can be reached at lward@dailyindependent.com or (606) 326-2661.