Nathan-SilvernailNathan Silvernail currently holds a Bachelor’s of Science in Aerospace Engineering and a Master’s of Science in Mechanical Engineering from Embry-Riddle Aeronautical University (ERAU).  He has been the lead engineer on eleven reduced gravity flights onboard NASA’s Reduced Gravity Aircraft (RGA) where he performed experiments pertaining to the development of on-orbit refueling of spacecraft and the study of fluid slosh dynamics on rotating bodies. He have designed the first working prototype of an advanced on-orbit refueling station that he fabricated using the CNC machines at ERAU and designed and built the prototype’s flight computer in his lab at the university. In 2012, he was one of 12 people worldwide to be awarded the Emerging Space Leaders Grant where he traveled to Naples, Italy to present his work at the International Astronautical Congress. That same year, he started his own engineering company that focuses on related research and development projects for private and government organizations in the aerospace community.

Student Research: Develop and maintain the ability to refuel space systems in Low Earth Orbit (LEO) and Geo-Synchronous Orbit (GSO) so as to further extend the mission capabilities of modern day Commercial Launch Vehicles (CLV’s); such as the Atlas V, Delta IV Heavy, and future Falcon Heavy.

Millstones and Objectives: To achieve the goal of on-orbit refueling, the Technology Readiness Level (TRL) of the storage and transfer systems that will be required to perform such refueling operations must be advanced. The advancement of the TRL is accomplished through a systematic testing approach that takes the system, or components within the system, through stages of experimental testing that start in the laboratory and end on-orbit. From ground testing in the Fuel Slosh Laboratory at Embry-Riddle Aeronautical University (ERAU) in Daytona Beach, Florida to microgravity testing onboard NASA’s Reduced Gravity Aircraft (RGA), Virgin Galactic’s SpaceShipTwo and the International Space Station (ISS), a Centaur derived on-orbit refueling system was/will be tested to determine the physical stability of the system and operational viability of an innovative propellant transfer approach that utilizes rotational fluid settling to negate the need for propellant management devices, cryogenic pumps and an active Attitude Control System (ACS).


Currently, Nathan has successfully accomplished the first three phases of this research; including laboratory testing and 8 experimental flights onboard NASA’s RGA with the sub-orbital testing phase scheduled to take place in the 4th quarter of 2013. During this campaign, he has been working with researchers from Massachusetts Institute of Technology’s (MIT) Space Systems Lab (SSL) to design and develop test equipment and procedures that would demonstrate the refueling system’s characteristics in “real-time” scenarios onboard the ISS. Supplementary to this investigation, he is working to develop computational models to predict the system’s behavior on-orbit, the models output parameters will be compared to that derived from physical testing to validate the modeling approach and verify the accuracy of the output parameters. The successful completion of the physical testing regime outlined and the computational models will provide an advancement of the propellant transfer component of the on-orbit refueling system’s TRL to level 6; opening the door for further sub-component testing to make on-orbit spacecraft refueling a reality.


In Nathan’s Own Words: During my time as a student, the Florida Space Grant Consortium was a very important influence on my career. Not only did they provide monetary support for my microgravity research projects, but I was awarded a Space Grant Fellowship that paid for the last year of my graduate schooling. Through the various Space Grant meetings I attended, I was able to meet professional engineers that opened doors for my research to advance to greater levels of testing. My main focus, ISS testing of my on-orbit prototype, became possible through discussions with the director of the Space Systems Lab at Massachusetts Institute of Technology; a discussion that was facilitated by the director of the FSGC, Dr. Mukherjee. Dr. Mukherjee provided constant moral support for my many endeavors and was always more than willing to lend a guiding hand in discussions pertaining to advancing my work and working to help secure collaborative efforts with the Center for Advancement of Science in Space (CASIS).