SAN FRANCISCO — After successfully launching its first Advanced Extremely High Frequency military communications satellite onboard a United Launch Alliance Atlas 5 rocket in August 2010, the U.S. Air Force planned to use the satellite’s powerful liquid apogee engine to boost the craft from its highly elliptical orbit into geosynchronous orbit. When that hydrazine-fueled engine designed to offer 45 kilograms of thrust failed to function due to a blocked fuel line, Air Force officials were forced to rely on the satellite’s smaller propulsion systems, including Aerojet Rocketdyne’s hydrazine-powered reaction engine assembly and xenon-fueled 4.5-kilowatt Hall effect thrusters with technology developed by Busek Co. Inc. and licensed to Aerojet Rocketdyne, which provide only 272 grams of thrust.
Those miniature thrusters fired for 10 hours per day over seven months to carry the 6,000-kilogram satellite to its orbital slot. Busek President Vlad Hruby said he never imagined the tiny thrusters would be cast in that role. When they succeeded, however, “it was a great advertisement for the technology worldwide,” he said.
Hruby founded Busek in 1985 to further development of plasma devices. For the firm’s first project, scientists and engineers tried to develop power-generation systems based on magnetohydrodynamics, the process of pushing plasma through a magnetic field. That research failed to produce its intended results but led the company toward the plasma technologies that are the core of Busek’s electric propulsion space systems, including AEHF’s Hall effect thrusters, which generate force by accelerating ionized gas through electrostatic and magnetic fields.
“A lot of the science done here is plasma physics and the aerospace engineering that goes with transforming plasma physics into working, useful devices,” Hruby said. “We have a full spectrum of propulsion and systems we are trying to advance into flight status, including Hall effect thrusters, radio frequency ion thrusters, electrospray thrusters, as well as green monopropellant systems.”
Busek is designing those systems for satellites of all sizes to raise orbits, change orbital inclinations, provide station-keeping and support proximity operations. Busek technology also can be used to support missions to near-Earth objects and interplanetary flight, Hruby said.
Busek Co. Inc. at a Glance
Top Official: Vlad Hruby, president and founder
Location: Natick, Massachusetts
What’s in a Name: Hruby named the company Busek after his maternal grandfather.
Hall effect thrusters have been a focus at Busek since the 1990s. Much of that work has been supported by Small Business Innovation Research (SBIR) funding from the U.S. Defense Department and NASA. “We own the technology for all Hall thrusters flown on U.S. spacecraft,” Hruby said.
Busek’s first Hall effect thruster, which was the first U.S. Hall effect thruster in space, was launched in 2006 on the Air Force Research Laboratory’s Tactical Satellite-2. A second Hall effect thruster helped propel the Air Force Academy’s FalconSat-5 spacecraft launched in 2010.
Busek also is developing electrospray technology for NASA and the U.S. Defense Advanced Research Projects Agency Phoenix program, an initiative designed to pave the way for robotic servicing of satellites in geosynchronous orbit and new satellite assembly methods.
In July 2013, NASA’s Space Technology Mission Directorate selected Busek, the NASA Jet Propulsion Laboratory in Pasadena, California, and the Massachusetts Institute of Technology (MIT) in Cambridge to develop electrospray propulsion systems for small satellites.
During the first phase of the project, Busek, JPL and MIT are refining thruster designs, building prototypes and conducting tests. In 2015, NASA officials plan to assess the competing technologies and select one for further development and possible spaceflight demonstration, said NASA spokesman David Steitz.
Busek completed electrospray thrusters for the NASA-European Space Agency Laser Interferometer Space Antenna Pathfinder, a mission scheduled for launch in 2015 to prove technologies for a gravitational-wave observatory. With funding from JPL, Busek conducted a six-year campaign to develop extremely precise microthrusters to counteract any slight forces that disturb the position of the spacecraft.
“It took a very concerted effort and synthesis of all kinds of programs to drive that program to its successful conclusion,” Hruby said.
With its emphasis on early stage technology, Busek’s main challenge has been finding ways to turn the systems it develops into spaceflight hardware. “All our technologies that are flying today started out as SBIR projects,” Hruby said. “We have been very faithful to the spirit of SBIR, striving to commercialize all the technology we develop.”
SBIR projects can suffer, however, if there is no mechanism to move them from development into flight. “We continually struggle with that,” Hruby said. “We have to wait until some time-constrained and budget-constrained flight program manager realizes he can’t accomplish his goals with existing technology and has to try something new. That’s when we get a call and get on a flight program.”
Nevertheless, Busek executives are getting those calls more frequently as NASA, the Defense Department and commercial firms focus on small satellites. “We are welcoming that trend with open arms because it increases the number of opportunities and because many of our devices naturally lend themselves to small satellites,” Hruby said.