Phd Defense by Alexandra Long

Event Details
  • Date/Time:
    • Tuesday July 10, 2018 - Wednesday July 11, 2018
      1:00 pm - 2:59 pm
  • Location: Montgomery Knight Building 317
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Summary Sentence: Development of a Passively Stable Pyramid Sail to Deorbit Small Satellites

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Alexandra Long
(Advisor: Prof. David Spencer)

will defend a doctoral thesis entitled,

Development of a Passively Stable Pyramid Sail to Deorbit Small Satellites


Tuesday, July 10 at 1:00 p.m.
Montgomery Knight Building 317


Orbital debris is a growing problem in low-Earth orbit, especially with a number of commercial companies intending to launch hundreds to thousands of micro-satellites into this regime with the goal of providing global internet service. The main goal of this research is to create a standardized, bolt-on system that will passively deorbit a small satellite from low-Earth orbit within 25 years to reduce the probability of collision with other objects and creating new debris. This will create an option for satellite designers that will easily allow them to follow end-of-life guidelines. The first step to design this device was to conduct a trade study that compares five technologies commonly proposed for deorbit purposes, which concluded that an aerodynamically stable drag sail is the favored choice. Next, the system level requirements to create a scalable system that included the required size of the sail for specific masses and orbit altitudes. It estimated the operational loads on the booms to develop structural requirements, and analyzed the material and thickness of the sail membrane to ensure it survives the atomic oxygen in low Earth orbit for the duration of the deorbit period. The stability was analyzed in a simulation that integrated the attitude and orbital behavior of a satellite with the drag sail and determined the apex half-angle for the system. A conceptual design for an ESPA-class drag sail is discussed, followed by the detailed design and prototype testing of a 1:10 scale CubeSat-class sail that will be launched as part of the Aerodynamic Deorbit Experiment. Finally, the two different sizes of SHEARLESS booms that were developed at NASA Langley and used in the drag sail designs were characterized with bending and torsion testing to determine the mechanical properties.


  • Prof. E. Glenn Lightsey (co-advisor) – School of Aerospace Engineering
  • Prof. Julian Rimoli – School of Aerospace Engineering
  • Mr. Mark Schoenenberger – NASA Langley Research Center
  • Mr. Les Johnson – NASA Marshall Space Flight Center


Additional Information

In Campus Calendar

Graduate Studies

Invited Audience
Public, Graduate students, Undergraduate students
Phd Defense
  • Created By: Tatianna Richardson
  • Workflow Status: Published
  • Created On: Jun 26, 2018 - 1:50pm
  • Last Updated: Jun 26, 2018 - 4:05pm