SAN FRANCISCO — As a college student in Prague, Tomas Svitek was fascinated by solar sails. It was the 1970s. NASA, the European Space Agency and Japan were all exploring whether solar sails could assist spacecraft missions to rendezvous with Halley’s Comet. Although solar sail technology was deemed too immature at the time, Svitek’s interest in the concept never waned.
More than three decades later, after fleeing Czechoslovakia as a political refugee during the Cold War, Svitek is putting the finishing touches on his solar sail. His small company, Stellar Exploration Inc. of San Louis Obispo, Calif., is the systems integrator for LightSail-1, the Planetary Society’s $2.2 million effort to build a kite-shaped, mylar solar sail that fits in a triple cubesat, a standardized satellite bus comprised of three 10-centimeter cubes.
If all goes well, LightSail-1 will fly in 2012, turning and tacking to maintain its orbit, while relaying images of the sail to viewers on Earth, said Lou Friedman, LightSail-1 program director and former executive director of the Pasadena, Calif.-based Planetary Society.
Stellar Exploration Inc. at a Glance
Mission: A small technology company focused on innovative and low-cost scientific and space exploration projects.
Established: 1997
Location: San Luis Obispo, Calif.
Top Official: Tom Svitek, President
Personnel: 10
Like Svitek, Friedman is a passionate advocate for solar sails, which propel spacecraft by harnessing the energy produced when photons emitted by sunlight bounce off sails comprised of reflective, lightweight material. “The lure is that you can travel without fuel,” said Friedman, who led the NASA Jet Propulsion Laboratory’s effort to develop a solar sail for the 1986 Halley’s Comet mission and subsequently wrote a book on the subject. “It’s the only technology we know that will take us to the stars.”
More immediately, solar sails offer a way to keep spacecraft in nontraditional orbits such as artificial Lagrange points, the gravitationally stable positions between planets or planets and stars. A space agency could station cargo at various places in the solar system with the help of solar sails to maintain the spacecraft’s position, Svitek said.
These and other potential applications have spurred space agencies around the world to design solar sails. Until 2010, however, no space agency had succeeded in using solar sails as the primary method of spacecraft propulsion.
That all changed in July when the Japan Aerospace Exploration Agency deployed a square, 14-meter solar sail known as Interplanetary Kite-craft Accelerated by Radiation of the Sun (IKAROS). IKAROS was spin-stabilized, meaning it whirled around in a circle to maintain the sail’s shape.
In January, NASA deployed its first solar sail: NanoSail-D, a 10-square-meter, polymer sail designed by engineers from NASA’s Marshall Space Flight Center in Huntsville, Ala., and NASA Ames Research Center in Mountain View, Calif. NanoSail-D, which also fit inside a triple CubeSat, unfurled its sail on Jan. 20. That sail remains in space but is slowly falling back to Earth, said Dean Alhorn, NanoSail-D principal investigator at NASA Marshall. NanoSail-D is designed to demonstrate solar sail technology and to offer a new way to drag satellites out of orbit once they have completed their missions. Alhorn is designing a drag sail for another microsatellite to demonstrate the use of solar sails to deorbit a spacecraft when it has completed its mission. He declined to name that satellite.
The Planetary Society’s LightSail-1 team plans to build on the design of NanoSail-D by using a similar boom to hold the sails in place and adding components to control the sail’s position. For deep space operations, the sail will remain in a fixed position for weeks at a time. To change its orbit, however, the LightSail-1 will be capable of sluing 90 degrees in 15 minutes, Svitek said.
LightSail-1 weighs 4.5 kilograms and is equipped with two cameras, on-board accelerometers, an attitude control system, six solar arrays for battery charging and telemetry components to relay data to ground stations.
Stellar Exploration is building the solar sail and associated electronics and acting as LightSail-1 systems integrator. A team of engineers at the California Polytechnic State University in San Louis Obispo is designing the spacecraft’s avionics, and students at the Georgia Institute of Technology are preparing to manage mission operations from their Center for Space Systems in Atlanta.
By July, the team plans to complete LightSail-1 assembly and testing, said Jim Cantrell, LightSail-1 program manager and president of Strategic Space Development, a consulting firm based in Tucson, Ariz. Then, the team will store the spacecraft and wait for a ride into orbit. Cantrell said he is confident that ride will come in 2012, but declined to specify the government mission likely to carry the solar sail into space.
In February, NASA announced that LightSail-1 was one of 20 cubesats approved as secondary payloads on rockets scheduled for launch in 2011and 2012. While that selection helps tremendously, Cantrell said, it is much harder to find a ride for LightSail-1 because it needs to go into an orbit far higher than most cubesats. To prevent atmospheric drag from interfering with flight, LightSail-1 is seeking a ride to an orbit of more than 825 kilometers, Friedman said.
If the launch is successful, the Planetary Society plans to follow it up with additional solar sail flights. The LightSail-1 team bought a complete set of spare parts that can be used to build LightSail-2. “It was cheap to buy the spares when we were buying the first set,” Cantrell said. The team also is discussing plans for a third solar sail, although that mission has not yet been defined, Cantrell added. The Planetary Society’s website advertises LightSail-3 as a “mission to demonstrate that solar sails can provide an early-warning station for geomagnetic storms triggered by eruptions from the Sun.”
Svitek already is busy crafting plans for future solar sails and other spacecraft components. After fleeing Czechoslovakia, Svitek earned a doctorate in planetary science from the California Institute of Technology in Pasadena. He later worked on small planetary missions at NASA’s Jet Propulsion Laboratory, served as principal scientist at Orbital Sciences Corp. of Dulles, Va., and led the science team for Early Bird 1, an imaging satellite launched in 1997 by DigitalGlobe of Longmont, Colo.
In 1997, Svitek established Stellar Exploration, where he serves as president. With 10 employees, the company develops miniature propulsion systems and advanced antennas for small satellites. The LightSail-1 project has comprised about 50 percent of the firm’s work for the last year. It also was the first time the company took on the task of integrating an entire spacecraft.
