Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Ion Drive: Improved Electric Propulsion Could Boost Lifetimes for Commercial, Government and Military Satellites

Researchers Jud Ready and Mitchell Walker prepare a carbon nanotube field emitter sample for measurements in the High-Power Electric Propulsion Laboratory of Georgia Tech’s School of Aerospace Engineering. (Georgia Tech Photo: Gary Meek)
Researchers Jud Ready and Mitchell Walker prepare a carbon nanotube field emitter sample for measurements in the High-Power Electric Propulsion Laboratory of Georgia Tech’s School of Aerospace Engineering. (Georgia Tech Photo: Gary Meek)

Abstract:
Researchers at the Georgia Institute of Technology have won a $6.5 million grant to develop improved components that will boost the efficiency of electric propulsion systems that are used to control the positions of satellites and planetary probes.

Ion Drive: Improved Electric Propulsion Could Boost Lifetimes for Commercial, Government and Military Satellites

Atlanta, GA | Posted on October 22nd, 2009

Focusing on improved cathodes for devices known as Hall effect thrusters, the research would reduce propellant consumption in commercial, government and military satellites, allowing them to remain in orbit longer, be launched on smaller or cheaper rockets, or carry larger payloads. Sponsored by the U.S. Defense Advanced Research Projects Agency Defense Sciences Office (DARPA-DSO), the 18-month project seeks to demonstrate the use of propellant-less cathodes with Hall effect thrusters.

"About 10 percent of the propellant carried into space on satellites that use an electric propulsion system is essentially wasted in the hollow cathode that is part of the system," said Mitchell Walker, an assistant professor in Georgia Tech's School of Aerospace Engineering and the
project's principal investigator. "Using field emission rather than a hollow cathode, we are able to pull electrons from cathode arrays made from carbon nanotubes without wasting propellant. That will extend the life of the vehicle by more efficiently using the limited on-board propellant for its intended purpose of propulsion."

To maintain their positions in space or to reorient themselves, satellites must use small thrusters that are either chemically or electrically powered. Electrically-powered thrusters use electrons to ionize an inert gas such as xenon. The resulting ions are then ejected from the device to generate thrust.

In existing Hall effect thrusters, a single high-temperature cathode generates the electrons. A portion of the propellant - typically about 10 percent of the limited supply carried by the satellite - is used as a working fluid in the traditional hollow cathode. The DARPA-funded
research would replace the hollow cathode with an array of field-effect cathodes fabricated from bundles of multi-walled carbon nanotubes. Powered by on-board batteries and photovoltaic systems on the satellite, the arrays would operate at low power to produce electrons without consuming propellant.

Walker and collaborators at the Georgia Tech Research Institute (GTRI) have already demonstrated field-effect cathodes based on carbon nanotubes. This work was presented at the 2009 AIAA Joint Propulsion Conference held in Denver, Colo. The additional funding will support improvements in the devices, known as carbon nanotube cold cathodes, and lead to space testing as early as 2015.

"This work depends on our ability to grow aligned carbon nanotubes precisely where we want them to be and to exacting dimensions," said Jud Ready, a GTRI senior research engineer and Walker's collaborator on the project. "This project leverages our ability to grow well-aligned arrays of nanotubes and to coat them to enhance their field emission performance."

In addition to reducing propellant consumption, use of carbon nanotube cathode arrays could improve reliability by replacing the single cathode now used in the thrusters.

"Existing cathodes are sensitive to contamination, damaged by the ionized exhaust of the thruster, and have limited life due to their high-temperature operation," Ready noted. "The carbon nanotube cathode arrays would provide a distributed cathode around the Hall effect thruster so that if one of them is damaged, we will have redundancy."

Before the carbon nanotube cathodes developed by Georgia Tech can be used on satellites, however, their lifetime will have to be increased to match that of a satellite thruster, which is typically 2,000 hours or more. The devices will also have to withstand the mechanical stresses of space launches, turn on and off rapidly, operate consistently and survive the aggressive space environment.

Part of the effort will focus on special coating materials used to protect the carbon nanotubes from the space environment. For that part of the project, Walker and Ready are collaborating with Lisa Pfefferle in the Department of Chemical Engineering at Yale University.

The researchers are testing their cathodes with the same Busek Hall effect thruster that flew on the U.S. Air Force's TacSat-2 satellite. In addition, the cathodes will be operated with Hall effect thrusters developed by Pratt & Whitney and donated to Georgia Tech. The researchers
are also collaborating with L-3 ETI on the electrical power system and with American Pacific In-Space Propulsion on flight qualification of the hardware.

The ability to control individual cathodes on the array could provide a new capability to vector the thrust, potentially replacing the mechanical gimbals now used.

The use of carbon nanotubes to generate electrons through the field-effect process was reported in 1995 by a research team headed by Walt de Heer, a professor in Georgia Tech's School of Physics. Field emission is the extraction of electrons from a conductive material through quantum tunneling that occurs when an external electric field is applied.

The improved carbon nanotube cathodes should advance the goals of reducing the cost of launching and maintaining satellites.

"Thrust with less propellant has been one of the major goals driving research into satellite propulsion," said Walker, who is director of Georgia Tech's High-Power Electric Propulsion Laboratory. "Electric propulsion is becoming more popular and will benefit from our innovation. Ultimately, we will help improve the performance of in-space propulsion devices."

####

About Georgia Institute of Technology
The Georgia Institute of Technology is one of the nation's top research universities, distinguished by its commitment to improving the human condition through advanced science and technology.

Georgia Tech's campus occupies 400 acres in the heart of the city of Atlanta, where more than 19,000 undergraduate and graduate students receive a focused, technologically based education.

Accredited by the Southern Association of Colleges and Schools (SACS), the Institute offers many nationally recognized, top-ranked programs. Undergraduate and graduate degrees are offered in the Colleges of Architecture, Engineering, Sciences, Computing, Management, and the Ivan Allen College of Liberal Arts. Georgia Tech is consistently ranked in U.S. News & World Report's top ten public universities in the United States.

For more information, please click here

Contacts:
Media Relations Contacts:
John Toon
404-894-6986


or Kirk Englehardt
404-407-7280

Copyright © Georgia Institute of Technology

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Automating DNA origami opens door to many new uses: Like 3-D printing did for larger objects, method makes it easy to build nanoparticles out of DNA May 30th, 2016

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Possible Futures

Automating DNA origami opens door to many new uses: Like 3-D printing did for larger objects, method makes it easy to build nanoparticles out of DNA May 30th, 2016

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Thermal modification of wood and a complex study of its properties by magnetic resonance May 26th, 2016

Nanotubes/Buckyballs/Fullerenes

Programmable materials find strength in molecular repetition May 23rd, 2016

Nanotubes are beacons in cancer-imaging technique: Rice University researchers use spectral triangulation to pinpoint location of tumors May 21st, 2016

Unveiling the electron's motion in a carbon nanocoil: Development of a precise resistivity measurement system for quasi-one-dimensional nanomaterials using a focused ion beam May 16th, 2016

New research shows how silver could be the key to gold-standard flexible gadgets: Silver nanowires are an ideal material for current and future flexible touch-screen technologies May 13th, 2016

Announcements

Automating DNA origami opens door to many new uses: Like 3-D printing did for larger objects, method makes it easy to build nanoparticles out of DNA May 30th, 2016

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Aerospace/Space

Deep Space Industries and SFL selected to provide satellites for HawkEye 360’s Pathfinder mission: The privately-funded space-based global wireless signal monitoring system will be developed by Deep Space Industries and UTIAS Space Flight Laboratory May 26th, 2016

Rice de-icer gains anti-icing properties: Dual-function, graphene-based material good for aircraft, extreme environments May 23rd, 2016

We’ll Leave the Lights On For You: Photonics advances allow us to be seen across the universe, with major implications for the search for extraterrestrial intelligence, says UC Santa Barbara physicist Philip Lubin - See more at: http://www.news.ucsb.edu/2016/016805/we-ll-leave-li May 17th, 2016

Smithsonian Science Education Center and National Space Society Team Up for Next-Generation Space Education Program "Enterprise In Space" May 11th, 2016

Grants/Awards/Scholarships/Gifts/Contests/Honors/Records

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Light can 'heal' defects in new solar cell materials: Defects in some new electronic materials can be removed by making ions move under illumination May 24th, 2016

Supercrystals with new architecture can enhance drug synthesis May 24th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic