In the past, large angle rotations of the International Space Station (ISS) have required significant usage of propellant. A 180 degree maneuver of the space station could use over 100 pounds of propellant at a cost of about $10,000 per pound. Dr. Nazareth Bedrossian, a Group Leader for Manned Space Systems at Draper, knew that this was an area where NASA could use his help.
Enter the Zero Propellant Maneuver (ZPM), a technique to rotate the ISS without using the stations thrusters and consuming propellant. "I had three Draper Laboratory Fellows work with me on this over the years and an opportunity arrived where they had to rotate the station," said Bedrossian, who recently was honored by NASA with an Exceptional Public Service Medal. "It was a Draper invented capability. We convinced them to try it out and they tried it out twice - first in November 2006 and then in March 2007."
The first flight demonstration rotated the station by 90 degrees and the second by 180 degrees. ZPM was developed by Bedrossian and Sagar Bhatt, a graduate student supported under the Draper Laboratory Fellow program, in collaboration with Dr. Yin Zhang, a professor of computational and applied mathematics at Rice University. ZPM is a new attitude control concept that takes advantage of the orbital environment - gravity and aerodynamics - to perform maneuvers with the ISS Control Moment Gyroscopes (CMGs). It has demonstrated how a non-propulsive maneuver can be accomplished using system dynamics. NASA describes it as being similar to the way a sailboat would tack against the wind.
Bedrossian, who has been involved in spacecraft simulation development, control system design and verification for over 15 years at Draper, is recognized by his colleagues as both a bright mind and a generous mentor for the next generation of aerospace engineers. "ZPM typifies Nazareth's ability to have an innovative technical solution and have it applied to a flight program and train the next generation of engineers," says Seamus Tuohy, Draper's Space Programs Director. By reducing propellant consumption, Tuohy notes that ZPM will allow for less stress on the ISS supply and logistics chain. The maneuver also avoids the solar array plume impingement and contamination issues associated with thruster firings.
Bedrossian has not had an easy road to success. He was born and raised in Cyprus, which was invaded by Turkey in 1974. Bedrossian was living in refugee camps before immigrating to the US as a teenager in 1977.
Upon arriving in the States, he lived with an uncle in northern Virginia while working and taking classes. Just as he was getting settled in his new country, another obstacle arrived. Bedrossian had contracted Hodgkin's disease, a cancer of the lymphatic system. He had to undergo chemotherapy and it took a year for him to recuperate.
Once he was healthy, Bedrossian fit everything he owned in his car and went to Florida to join friends. He hoped to gain admittance to the University of Florida but was not accepted the first time he applied; the school suggested that he attend community college and then transfer. His persistence ultimately paid off. After a year and a half of community college, Bedrossian was accepted by the University of Florida. He graduated with high honors in 1984, earning a degree in Mechanical Engineering.
The next step would be graduate school and Bedrossian was accepted by both MIT and Stanford. However, no scholarships were available, posing yet another challenge. "I stayed in Florida in 1985, looking for funding, and then I took a trip up to MIT to visit some professors and see if there
were any TA positions available," said Bedrossian. "Most of them didn't have anything. However, one professor, Warren Seering, said there's a place called Draper that offers support for graduate students under the Draper Laboratory Fellow program, and maybe you ought to apply to them."
Bedrossian visited Draper and talked with a number of staff, including current Vice President of Programs Darryl Sargent. He was ultimately awarded a Draper Laboratory Fellow appointment and began working at the lab during the summer of 1985. Even the move to Boston had an inauspicious start. "Darryl likes to tell the story about how I came up there. Housing wasn't available and for two weeks I lived in a campsite in Littleton, a KOA," said Bedrossian. "It was pretty fun. I enjoyed it there, sleeping in a tent."
Bedrossian earned his Masters and PhD in Mechanical Engineering from MIT. "Essentially, Draper paid for school. You can't get a better deal than that," said Bedrossian. "I also worked a couple summers as staff. That was actually nice earning extra money." Once he finished his PhD work, Bedrossian became a full-time staff member. He moved to Houston in late 1991, working for Sargent's Space Systems group.
As NASA acknowledges his public service, Bedrossian is still making vital contributions to the agency and its future plans. Project Constellation, which aims to send astronauts back to the moon by 2020, is relying upon a new generation of rockets - Ares I, which will carry astronauts into space aboard an Apollo-like capsule, and Ares V, an unmanned heavy-lift cargo ship. Draper is designing the controller to fly this next generation of NASA rockets. Bedrossian serves as task leader for the Ares I launch vehicle attitude control design and Draper is helping the Marshall Space Flight Center design avionics and flight software for the platform. The technical challenges are daunting. Ares I has a long, slender body - the ratio of height to body diameter is 18:1 - which will actually bend as it moves in flight. "It's a very flexible, tall body that you need to steer," says Tuohy. Bedrossian is applying his knowledge in control of flexible structures to keep the Ares 1 stable during its flight.
As always, Bedrossian is focused on both his projects and what is being done to prepare the next generation of aerospace engineers. In 1998, he established a Draper Laboratory Fellow program at Rice University in Houston and the program has been a huge success with 13 graduates. For 2008, the program has 7 fellows.
And Bedrossian hasn't stopped there. He is looking to soon establish a fellow program at Draper's new location in Huntsville, Alabama. "The Draper Laboratory Fellow program provides another means by which Draper serves the national interest by developing the next generation of guidance, navigation and control talent," said Bedrossian, who is now giving back to the program which offered him such a tremendous opportunity.