Professor Gilchrist is Co-PI in the development of the Nanoparticle Field Emission Thruster (nanoFET).
Using highly accelerated nanoparticles it is possible to create a paradigm shift in electric space propulsion
technology. The nanoFET concept uses microelectromechanical (MEMS) structures to transport, charge,
extract, and electrostatically accelerate nanoparticles for propulsive thrust in new ways that can
substantially improve performance and mission capabilities. The nanoFET was selected by NASA’s
Institute for Advanced Concepts (NIAC) for further development and recently has been funded by
AFOSR. Highly accelerated nanoparticles is also being explored for nanoprinting, material processing,
and biomedical applications.
Professor Gilchrist was an instrument Co-I on the NASA Scout mission development, The Great Escape
(TGE), developed by Southwest Research Institute. He was responsible for the development of the mission’s
Langmuir Probe (LP) instrument intended to provide measurements of Mars ionsophere plasma density and electron
temperature as well as measurements of integrated solar ultraviolet flux outside of the ionosphere.
As a Co-I for NASA’s ProSEDS electrodynamic tether propulsion mission, developed is to fly on a Delta-II
in 2003, Professor Gilchrist was responsible for providing both plasma diagnostics and high-voltage control
instrumentation. This includes a Langmuir probe and spacecraft potential monitor designed to rapidly operate in a
variable plasma environment. In addition, he was responsible for providing a high-voltage tether current control and
monitoring instrument. Of special interest, was that Professor Gilchrist also lead a group of University of Michigan
students (over 100) to build a small, independent instrumented satellite for the ProSEDS mission to be placed at the
end of its tether to provide enhanced tether dynamics data to NASA.
He was Principal Investigator for the SETS experiment on the 1996 TSS shuttle mission (STS-75), he lead a
team of researchers from the University of Michigan, Utah State University, and Stanford University in the
investigation of tether electrodynamic fundamentals in the Earth's ionosphere and the use of space tethers for
scientific and technological applications. The SETS team specifically addressed questions pertaining to system level
current-voltage characteristics and ionospheric effects as well as the use of tethers as long baseline double probes to
measure natural electric fields, as long receiving antennas, as a method to enable simultaneous multipoint in-situ
ionospheric measurements, as a remote electrical reference for spacecraft charging studies, and the study of
electromagnetic pulse propagation along a conductor in a magnetized plasma. The TSS-1R experimental results,
which the SETS team helped generate, have been pivotal in establishing the ability to drive high currents through the
ionosphere for power generation and propulsion applications. Professor Gilchrist made specific contributions in
identifying mechanisms for the highest tether currents generated during the mission.
Professor Gilchrist was Co-PI for an AFOSR program to make fundamental plasma electromagnetic
measurements to support the development and integration of closed-drift, hall-effect electric thrusters for next
generation spacecraft. This included establishing quantitative measures of amplitude and phase distortion to
electromagnetic signals propagating through plasma plumes. He has led the development of advanced microwave
and millimeter wave interferometers for highly accurate plasma density measurements for electric propulsion
diagnostics. In addition, techniques using Ion Acoustic Wave (IAW) propagation in a moving plasma to establish
ion temperature and drift velocity has been developed by his students. He was also Co-I on a follow-on AFOSR
program to develop a high power to develop a high power Hall thruster. He and his students were responsible for
developing 17, 35, and 70 GHz interferometers which are being used to investigate small scale plasma structure near
the primary ionization and acceleration zones of EP thrusters.
He was PI for a NASA funded study of space tether application to ionospheric/thermospheric research and
was organizer for a 1994 international workshop on the subject with over 50 participants from five countries. The
unique ability to use space tethers for simultaneous, multipoint measurements was of special interest to the
participants. Professor Gilchrist, in 1994, also led a team of University of Michigan students, engineers, and
collaborating organizations (NASA Marshall Space Flight Center, Lockheed-Martin Corporation (Denver), Tether
Applications Incorporated, University of Texas (Dallas), University of Alabama (Huntsville), and NASA Goddard
Space Flight Center) in proposing a space tether mission to the lower thermosphere/ionosphere called AIRSATT
(Atmospheric-Ionospheric Research Satellite using Advanced Tether Technology). The AIRSATT mission was
selected by the University Space Research Association as one of six (out of sixty-six) proposals for an in-depth
Phase 1 study for possible flight as part of a NASA funded program called STEDI (STudent Explorer
Demonstration Initiative).
He was also PI for an Air Force program to investigate theoretical issues of propagating artificially generated
relativistic electron beams in space. This effort has generated quantitative models describing beam propagation, the
scattering by the atmosphere, and the importance of the Earth's magnetic field in confining beam spread. He was
responsible for early relativistic particle models used in describing ionization effects in the mesosphere and
supported the initial assessment of relativistic electron beam induced modifications to atmospheric electric fields.
Professor Gilchrist was a Co-Investigator on the 1992 high-energy electron beam CHARGE-2B tethered
rocket experiment with responsibility for the science design of its neutral gas payload charge-neutralization
experiment. He participated in both the VCAP Experiment on the Spacelab-2 Shuttle mission and the CHARGE-2
tethered rocket experiment which was a conducting tether experiment testing some of the TSS concepts.
His doctoral research at Stanford University was divided into two primary areas: a) investigations of
electrodynamic effects due to electron beam and neutral gas emissions into a space plasma; and, b) radar and
theoretical investigations of energetic electron beam generated artificial plasma density structures in the ionosphere
using rockets and spacecraft. His masters thesis research, sponsored in part by a General Electric Fellowship, at the
University of Illinois involved implementing an ionospheric total electron content radio measurement experiment
optimized for nighttime application in the E and lower F regions of the ionosphere. The experiment was based on
Faraday rotation, using a ground based HF transmitter, rocket borne receiver, and digital signal processing to extract
the desired signals.
Professor Gilchrist has also held both technical and supervisory positions in industry (Watkins-Johnson
Company) over a twelve-year period associated with microwave integrated circuit and subsystem design for radar
and ecm applications. Research activities included: phased array radar, low-noise amplifiers, phase-shifters, and
microwave sample-and-hold circuits.
