Designing the best method for cleaning up trash in space has led to a first place win for AE students in the 2010-11 American Institute of Aeronautics and Astronautics Foundation undergraduate team space design competition.
The AE team, Sayonara Space Systems, won the top honor for their project, “ADIOS: Agile Debris-in Orbit Solution.” The contest required teams to design a spacecraft capable of removing large-sized debris that orbits around Earth at an altitude between 540 and 600 miles high, and an inclination between 82 and 83 degrees. Spacecraft were required to feature a robotic arm, capable of placing “deorbiting packs” on individual pieces of debris.
The AE team began the work in Fall 2010 as their senior design project. Members are
• Devin Bergman, in charge of orbital mechanics, navigation and control
• Jason Goerlich, in charge of structures and thermal protection system
• Christopher Habib, in charge of the overall mission architecture, systems analysis and cost model
• Jason Hewkin, in charge of the debris removal system
• Philip Hornstein, in charge of propulsion systems
• Coralie Jackman, in charge of avionics systems
• Tucker Gritton and Nathan Dostart, freshmen interns
• Daniel Morgan and Dushyant Rao, course teaching assistants
• Prof. Soon-Jo Chung, project advisor and course instructor
From left: Jason Hewkin, Devin Bergman, Jason Goerlich; Philip Hornstein; Coralie Jackman; Tucker Gritton; Christopher Habib, and Nathan Dostart
As the first-place team, Sayonara is invited to participate in the AIAA Space 2011 Conference & Exposition to be held in Long Beach, California, September 27-29. Hewkin is the team’s representative.
The U.S. Space Surveillance Network tracks space debris, ranging from large, spent launch vehicles, to tiny flecks of paint. The network follows about 19,000 objects larger than 10 centimeters; 500,000 particles that are 1 to 10 centimeters in diameter; and tens of millions of particles smaller than 1 centimeter. In addition to littering outer space, the debris can pose a danger of colliding with satellites, rockets and other craft sent into space on missions.
The AE team prioritized retrieving spent rocket bodies – each weighing 1½ tons – and removing them from orbit through the most cost-efficient means possible. “I think we won because we (designed a plan to get) the most mass down with the least amount of money,” said Hornstein, speaking for the team.
The team arrived upon a clever, cost-efficient solution, but only after they scrapped original plans on which they had worked the first full semester.
“The first semester we looked at using a propellant (to bring the captured debris back to earth),” Hornstein said, “but we came to the conclusion that nothing that could be used would be efficient enough: an electrical system would require too much power for the size (of spacecraft) we wanted, and a chemical system would require too much fuel.”
“Our first review, we did have an electrical propellant system. Coralie (in charge of avionics) concluded there was not enough power to run it. We had to go back to the drawing board.”
Using tethers to allow for a passive deorbit from space arose as an alternative. Hewkin researched the use of tethers, and Hornstein employed physics to prove they could work.
In the final design, the team developed plans for a launch vehicle to carry into space 16 cube-shaped ADIOS spacecraft stacked upon each other. Each would be equipped with capture mechanisms on one end and tethers on the other. Upon the ADIOS crafts’ release, the craft would separate, and sensors would direct each to dock on the side of a spent rocket body. Claws from the ADIOS would latch onto the spent rocket, then the tethers, consisting of 7-kilometer-long cables, would release, dragging and slowing both the ADIOS spacecraft and captured debris, pulling both out of orbit, and, eventually, bringing them back to Earth.
The team estimated the whole process would take about 6 months and cost about $17,000 per kilogram of mass deorbited, for a total project budget of $385 million. In addition to designing the craft, the team had to design a business plan, estimating costs for manpower needed to conduct the mission, and estimating costs of components, based on several calls to aerospace companies. The AIAA’s requirements limited budgets to no more than $400 million.
Every year the AIAA Foundation sponsors several design competitions that ask students to solve real-world design problems. These respected competitions give America’s best student designers a chance to put their talent front and center for the aerospace world.